<figure><img src="image_115.png" /></figure>

geographical patterns of plant diversity across the whole latitudinal zone of the region. Recent study reported bias-corrected diversity patterns of global woody plants, and reported a skewed latitudinal gradient in species diversity, peaking in the mid-latitudes of the Northern Hemisphere (southern China). A latitudinal diversity gradient is one of the best-recognized macroecological patterns, and its underlying mechanisms are considered to be due to energy/climatic gradients, and/or tropical niche conservatism, but no consensus has yet been reached. A thorough exploration of the drivers of the skewed latitudinal diversity patterns of woody plants in the region would provide further insight into the geographic, ecological, and evolutionary forces shaping biodiversity. In this presentation, we introduce the results of the examination of the contribution of plant taxonomic components to the biased latitudinal diversity gradient. Then, we aim to identify taxonomic levels, groups, and areas to focus on and in the future and organize hypotheses to be tested in order to elucidate the mechanism of biased latitudinal diversity pattern.

## S.44.2 Origin and Australian paleoclimate drives biotic exchange patterns across Wallace's Line

Elizabeth M. Joyce

Systematics, Biodiversity and Evolution of Plants, Ludwig Maximilian University of Munich, Munich, Germany

The convergence of the Sunda continental shelf (Malaysia, parts of Indonesia and the Philippines) and the Sahul continental shelf (Australia and New Guinea) from c. 25 Mya was a significant event in global biogeography that resulted in the exchange of previously isolated floras (the 'Sunda-Sahul Floristic Exchange'; SSFE). Despite the importance of the SSFE in shaping the flora of the region, much remains to be understood about the processes and patterns underlying it. To address this, we used Angiosperms353 target capture data to generate the most densely sampled phylogenetic tree of angiosperm order Sapindales to date, with 448 samples and c. 85% of the genera represented. Our tree resolves the relationships between Meliaceae, Simaroubaceae and Rutaceae and indicates that Nitrariaceae, Biebersteiniaceae and Sapindaceae emerged early in Sapindales, but the order of di-

vergence remains unclear. Bayesian dating with 29 rigorously assessed fossil calibrations indicates that most Sapindalean families arose in the Cretaceous. We then integrated target capture data with legacy Sanger data to produce species-level phylogenetic trees of Sapindales families. Biogeographic analyses of the dated, species-level trees support Sundanian origin for Sapindales families, confirm the eastward bias in exchange from Sunda to Sahul, and highlight the importance of Wallacean emergence in facilitating the exchange. Most interestingly, the results indicate that for some lineages, an origin in Sunda and subsequent colonisation of Wallacea and Sahul explains the observed eastward bias in exchange, while for others, ancestors were present in Sahul, but extinction coincident with Miocene aridification likely contributed to the eastward exchange bias. This study has shed new light on Sapindalean evolution and the SSFE, and emphasises the importance of considering ancient evolutionary history when attempting to understand recent and current biogeographic processes.

## S.44.3 Cenozoic dynamics of beta diversity in East Asian angiosperm woody plants: cooling and increased fluctuation of climate drive dist

Shogo Ikari¹, Takayuki Shiono¹, Kubota Yasuhiro¹

1 Faculty of Science, University of the Ryukyus, Japan

We focused on the impact of paleoclimate changes on large-scale taxonomic sorting related to geography; specifically, how cooler and warmer climatic conditions affect the distance-dependency of betadiversity. Using a dataset of Cenozoic fossil assemblages of angiosperm woody plants (7,468 data points; 310 genera in 95 families) in the Japanese portion of the East Asian archipelago (except Ryukyu islands), we modeled the distance-dependency of genus turnover (pairwise compositional dissimilarity) through the Oligocene, Miocene, Pliocene, Pleistocene, Last Glacial Period, Holocene, and present day. The genus turnover of angiosperm woody plants was significantly correlated with geographical and climatic distance only in the Last Glacial Period, Holocene, and present day. During
<figure><img src="image_116.png" /></figure>

theOligocene to Pliocene, the warmer periods, ge-
nus turnover was mostly independent of geograph-
ical distance. Spatial/climatic distance-dependent
turnover under colder environments involved a cli-
mate-induced sorting process to spatially diversify
woody-plant assemblages across the archipelago.
Moreover, the predominance of distant-indepen-
dent turnover suggested the effect of dispersal re-
lease under warmer, stable climates. Our findings
suggest that future tropicalization in temperate
habitats could promote geographical homogeniza-
tion of biodiversity patterns.

S.44.4 Historical
biogeography of Maesa
(Primulaceae) with an
emphasis on the Indo-
Australian Archipelago

Pirada Sumanon¹,², Timothy M.A.
Utteridge³,⁴, Henrik Balslev² & Wolf L.
Eiserhardt²,³

1 Silpakorn University, Sanam Chandra Palace
campus, Nakhon Pathom, Thailand. 2 Aarhus Uni-
versity, Aarhus, Denmark. 3 Royal Botanic Gardens,
Kew, UK. 4 Singapore Botanic Gardens, Singapore

The Indo-Australian Archipelago is recognized as
one of the world's most geologically and bioge-
graphically complex areas with exceptional floristic
diversity. These islands are situated between main-
land Southeast Asia and Australia, acting as an area
of floristic interchange. However, the pathways of
plant dispersal across the region are still unclear.
Although west-to-east dispersal into the Pacific is
detected in several plant groups, the generality of
this pattern remains to be tested. Maesa is a genus
of shrubs, trees, or woody scramblers in the family
Primulaceae distributed in the palaeotropics from
Africa to the Pacific comprising approximately 200
species. In this study, we reconstructed dispersal
events of Maesa focusing on the Indo-Australian
Archipelago and the connection to continental Asia
and the Pacific islands. We used a comprehensive
species-level phylogeny generated from genomic
(target sequence capture) data for molecular dat-
ing and ancestral range estimation. The phylogeny
showed several strongly supported clades, includ-
ing three geographically structured Asian-Pacific
clades. The Asian-Pacific lineage diverged from its
African relatives ca. 15 Ma and established in Conti-

nental Asia-Papuasia-Philippines ca. 11 Mya. Howev-
er, the recent diversity of the genus in the Asia-Pacif-
ic is a result of rapid radiations that happened ca. 5
Mya possibly related to a warming phase and rapid
orogenesis. Papuasia and Continental Asia are in-
ferred as major sources of Maesa. We detected two
west-to-east dispersal trends: from continental Asia
to west Malesia and from Papuasia to Pacific Is-
lands. No connecting path is recovered which might
be due to incomplete sampling especially from the
Philippines. This study is the first to explore histori-
cal biogeography of the genus Maesa. Our investi-
gation into the biogeographic history of the genus
reveals the events that shape the current distribu-
tion of Maesa and shed light on the connectivity be-
tween the complex Indo-Australian Archipelago and
neighbouring islands and continents.

S.44.5 Phylogenomics,
pollination biology, floral
chemistry, and historical
biogeography of Western
Australian Darwinia
(Myrtaceae)

Patricia W. Chan¹,⁴, Ashley Hamersma²,
Barbara Rye³, Matthew Barrett³,⁴, Thomas
J. Givnish¹

1 University of Wisconsin - Madison, Wisconsin, USA.
2 University of Florida, Florida, USA 3 Western Aus-
tralian Herbarium, Western Australia, AU. 4 Austra-
lian Tropical Herbarium, Queensland, Australia

We are using a variety of approaches to analyze
the relative importance of various drivers of species
diversification in the large, relatively young, mor-
phologically diverse genus *Darwinia* (Myrtaceae)
from Western Australia. This group is ideal for such a
study given the narrow endemism of many species,
the sky-island biogeography of several taxa, the ap-
parent lack of long-distance seed dispersal across
the group, and the striking diversity of inflorescences
and associated pollinators, with the latter including
birds, marsupials, and several groups of insects. We
are developing a Myrtaceae bait kit for phyloge-
nomic studies of *Darwinia*, and have sequenced and
analyzed several hundred single-copy nuclear loci.
We are extending these studies now to construct
and date nuclear and plastome phylogenies, to re-
construct relationships, character-state evolution,
species diversification rates, and historical bioge-
<figure><img src="image_117.png" /></figure>

ography in *Darwinia*. We are also investigating the reproductive ecology and pollination syndromes of several representative *Darwinia* species through studies of pollinator behavior, floral morphometrics, and floral volatile and nectar chemistry. Data resulting from these studies will be integrated into analyses of the drivers of taxonomic and morphological diversification in *Darwinia*. This research will shed light on speciation, endemism, adaptive radiation, coevolution, and convergence in a large, threatened clade from the Western Australia biodiversity hotspot based on research by collaborators at the Western Australian Herbarium, Australian Tropical Herbarium, King's Park Botanic Garden, and the University of Wisconsin-Madison.

## S.44.6 Phylogeography and conservation of Pedicularis (Orobanchaceae) in the Hengduan Mountains biodiversity hotspot

Jared B. Meek¹, Jenni U. Jones¹, Richard H. Ree², Deren A.R. Eaton¹

1 Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, USA.

2 Integrative Research Center, The Field Museum, Chicago, USA

*Pedicularis* (Orobanchaceae) is a genus of herbaceous hemiparasitic plants with highly diverse floral morphologies. It includes ca. 600 species worldwide, more than half of which are native to China and endemic to the Hengduan Mountains, where their greatest diversity is found. Over the past decade, multiple phylogeographic scenarios have emerged to describe the impacts of mountain uplift, Quaternary glacial cycles, and climatic transitions on plant diversification across the Hengduan Mountains. While some studies have documented these large-scale dynamics for species across this region, few have used population genomics to quantify impacts of geographic barriers on population structure. This research highlights the phylogeographic histories of twelve widespread *Pedicularis* species in the Hengduan Mountains, where it is common to find many species of *Pedicularis* flowering in sympatry. With an assembled dataset of ~1,000 specimens, we used a modified ddRAD approach to determine the population structure and divergence time estimates for these twelve species, as well as putative geographic barriers affecting their dispersal ability across the mountain range. Additionally, we compared the genetic diversity between contemporary (post-2018) and historical (pre-2000) *Pedicularis* samples collected throughout the Hengduan Mountains to reveal areas of gene flow, highlighting potential conservation implications of recent infrastructure development in the region.

## S.45 TOWARDS A MORE ETHICAL SCIENCE: DECOLONIZING BOTANICAL RESEARCH. SESSION 1

### S.45.1 Publishing as ethics: decolonizing as a means towards equitable publishing

Cynthia T. Fowler¹

1 Sociology and Anthropology Department, Wofford College, Spartanburg, USA

As a means for contributing to the session on decolonizing botany, this paper presents a critical analysis of academic publishing. Because science

is a multipronged institution, decolonizing it requires also liberating the colonial hold on the ways information is shared and, moreover, on the information itself. The critical analysis in the presentation is made from my perspective as a publisher and editor with the Society of Ethnobiology and the University of Arizona Press. I also build upon my experiences as a transdisciplinary field researcher, author, and peer reviewer. Additionally, I share key moments from dialogues within the ADIE (Allying for a Diverse and Inclusive Ethnobiology) community related to equitable publishing and data sovereignty about: ethics; iterative project design; research approvals and rapport; co-authoring; regulations, standards
<figure><img src="image_118.png" /></figure>

and practices; funding and advocacy; procedures for managing vouchers; and ethnobiological methods. By raising questions about what academic publishing would look like in a world where science is decolonized, this presentation provokes considerations related to botanical research. For example, IBC conference attendees might discuss data sovereignty, open access, co-authoring, multilingualism, rank and tenure evaluations, rematriating voucher specimens, collaboration, Indigenizing methods, and epistemological justice. What efforts are being made towards decolonizing publishing? Publishing has made some progress towards decolonizing; particularly with open access, international hip, ethics codes, data sharing, and editorial support for scholars with diverse language backgrounds. What are the barriers in these arenas and what are some additional obstacles to a more equitable publishing? Why are these barriers and obstacles in place, and how could they be overcome? Working within a framework of decolonial theory and born from practical experience, this paper problematizes publishing standards in the colonizers' worlds while it offers pluralizing and otherwise as conceptual mechanisms for decolonizing publishing.

## S.45.2 Gender equality and the visualisation of women in ethnobiological research: advances and perspectives

Ana H. Ladio¹, Irene Teixidor-Toneu²

1 INIBIOMA (CONICET-Universidad Nacional del Comahue). Quintral 1250, S.C. de Bariloche, Argentina. Email: ahladio@gmail.com. 2 IMBE, Aix Marseille Univ, Avignon Univ, CNRS, IRD, Marseille, France

Achieving gender equality and ensuring a fair representation of women in ethnobiology (and other disciplines) is still challenged by biases deeply rooted in the academic system. These biases lead to practices that reaffirm inequalities towards women. The existence of a gender hierarchy gives rise to a tripartite set of problems that may be manifested in the practice of ethnobiological research. These problems are: 1) maintaining or exacerbating such a hierarchy; 2) failing to examine differences, being insensitivity to differences, and treating people the same when they should be treated differently; and 3) using double standards, treating different groups differently because of their position within a social hierarchy. To explore gender biases in ethnobotan-

ical research, we re-examine our own published works, evidencing gender misconceptions that have become evident in the discursive field and have operated in the conception, methodology, and interpretation of our results. Our conclusions reinforce the idea that it is necessary to open new perspectives that allow considering the feminine dimension when studying place-based knowledge and practice, since it is still veiled in much of the ethnobiological scientific production. The set of problems evidenced in our work and that of other, synthesized in the so-called triangle of bias, can only be corrected with an integral gender approach. Furthermore, we highlight the importance of further research to describe local gender asymmetries in the protagonists' own terms

## S.45.3 Co-authorship with Indigenous, Afrodescendant, and local peoples: Opportunities and responsibilities of academia

Ina Vandebroek¹, Fleur de Marie Fitzpatrick²

1 Department of Life Sciences and Caribbean Centre for Research in Bioscience, Faculty of Science and Technology, The University of the West Indies Mona, Kingston, Jamaica, West Indies. 2 Department of Learning and Participation, The Royal Botanical Gardens at Kew, Richmond, London, UK.

Academia has a long history of not acknowledging and/or appropriating the research contributions of traditional knowledge holders in interactions with Indigenous, Afrodescendant, and local communities. Recognizing this history underscores the continued need for more equitable and respectful science, advocating for genuinely collaborative research, and embracing co-hip on scientific publications. This approach presents opportunities for expanded allyship networks, facilitates mutual learning experiences, enriches research methodologies, incorporates diverse perspectives, and fosters ethical and sustainable research outcomes. Co-hip, for example, provides a platform for Indigenous and other local community members to actively participate in the research process, ensuring their voices, perspectives, and knowledge are properly acknowledged and represented. Moreover, collaborative research is impactful when embedded in long term relationships that support agency and self determination with the communities involved. Additionally, papers
<figure><img src="image_119.png" /></figure>

written collectively are more likely to be expressed
in accessible language, enabling more people to
build on research and rendering them more mean-
ingful for posterity. This collaborative model fore-
grounds the significance of cultural sensitivity and
respect for local traditions, incorporating the right
to veto the publication of culturally-sensitive infor-
mation. When co-hip is truly collaborative it will pro-
mote trust and mutual respect, giving communities
a sense of ownership and control over the research
process and its outcomes. On the other hand, it is
essential to identify and address challenges asso-
ciated with co-creation of knowledge and co-hip,
such as power dynamics, resource imbalances, and
the risk of tokenism. Consequently, research meth-
odology should be informed and grounded in em-
pathy as communities may have suffered trauma in
the past from exploitative research and colonialism.
These challenges should inform future strategies
dedicated to nurturing more meaningful and bal-
anced partnerships.

groups who gather for ceremonies. An ethnographic
case study, using methods drawn from Participatory
Action and Social Movement Research, analyzed the
environmental injustices in a historical and current
context. Our research is grounded in learning from
those who have mobilized this movement, espe-
cially the Indigenous peoples. We documented the
spiritual, sacred connections to the land, and how
sovereignty rights are tied to CHamoru identity and
values. U.S. law disregarded Indigenous perspec-
tives which play a vital role in plant-human spiritual
frameworks and the protection of Indigenous bio-
cultural heritage. Despite opposition from the island
community and demands for environmental justice,
the Department of Defense bulldozed the forest at
Tailalo'. More destruction is on the way at Litekyan.
This symposium, with a call to action from within the
botanical research community, excites us. Maria,
traditional knowledge holder and activist, and Else,
scientist and activist, share how they support each
other to amplify Indigenous voices.

S.45.4 Biocultural heritage
of Litekyan in Guam:
connecting stories of
spirituality and resistance

Else Demeulenaere¹, Maria Hernandez May², Stefanie M. Ickert-Bond³

1 University of Guam Center for Island Sustainability and Sea Grant, University of Guam, UOG Station, Mangilao, Guam. 2 Micronesia Climate Change Alliance, Guam. 3 UA Museum of the North Herbarium and Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, USA

The Mariana Islands are characterized by a rich bio-
cultural diversity. The CHamoru people of Guam (the
southernmost island) have coexisted sustainably
with their islands' biotic communities. When the sa-
cred lands of Tailalo' and Litekyan became threat-
ened by military expansion on Guam, a social move-
ment advocated for the protection of the CHamoru
peoples' biocultural heritage and the return of their
lands. Maria Hernandez May, an Indigenous CHamo-
ru woman and daughter of a lineage of original
Litekyan landowners, continues the legacy of her
ancestors in her fight to get their land back. She is at
the forefront of the movement, advocating for en-
dangered species, CHamoru culture and ancestral
land. The social movement also represents the voic-
es of the traditional healers, fishermen and cultural

S.45.5 Using photo
identification and digital
methods to empower local
communities to document
their own botanical
knowledge

Alexander M. Greene¹, Irene Teixidor-
Toneu², Guillaume Odonne¹

1 LEEISA, (CNRS, Université de Guyane, IFREMER), Cayenne, France. 2 Laboratoire IMBE (IRD, Aix-Marseille Universités), Marseille, France

The identification of plants according to the Lin-
naean system of taxonomy is a cornerstone of eth-
nobotany, allowing the discipline to be a compar-
ative science. To accomplish plant identification,
ethnobotanists have long relied on the collection
of voucher specimens and their deposition in her-
baria. Nevertheless, the complexity of botanical col-
lecting sometimes hampers the process of local
communities self-conducing their own ethnobo-
tanical inventories. Here we bring attention to a new
set of methods which could help facilitate this goal:
the collection of photographic vouchers and their
deposition in digital repositories. The ever-improv-
ing quality and ubiquity of smartphone cameras,
photographic citizen science applications like Pl@
ntnet and iNaturalist, and deep learning techniques
of automated photo identification are contributing to a slow revolution in the role of digital data in the field sciences. We propose photographic vouchers as a valid, scientifically rigorous and locally adapted method to inventory local botanical knowledge for and by communities and lay out guidelines for their use.

### S.45.6 Ethnobotany in service of food, land, and data sovereignty: examples and barriers

Alex C. McAlvay¹

¹The New York Botanical Garden, New York, U.S.A

Ethnobotany, like many fields, was shaped by early Western imperial efforts to colonize people and lands around the world and understand and extract natural resources. Over the last several decades, many ethnobotanists have worked to re-envision the goals of ethnobotany as an anti-colonial science which supports local communities' rights to self-determination. Three case studies will be presented that seek to support food, territory, and data

sovereignty of Indigenous Peoples and local communities as well as the challenges faced and lessons learned. First, in many parts of the world, traditional, climate-resilient crops and cropping practices are being replaced with high-input, introduced grains promoted by international and governmental policies. I share work to revitalize traditional grain mixtures in Ethiopia that are being discouraged by agricultural policy. Second, Globally, Indigenous Peoples have shaped landscapes through centuries or millennia of plant stewardship. In the Pacific Northwest of North America, territorial rights can be tied to laws based on misconceptions about traditional land stewardship. I share examples from land-rights cases that incorporate ethnobotany as evidence. Finally, herbarium specimens can contain not only biological data, but also cultural data—notes on local names and uses. In many cases this data was collected without formal approval from communities and/or before Free Prior Informed Consent became standard. I share work by a global consortium of herbaria working to reunite this data with source communities and explore options for community control of their data. Reflections are presented on the social, legal, and ethical complexities involved in these cases as well as faced by contemporary ethnobotanists in general.

## S.46 AEROBIOLOGY. ADVANCES IN THE ATMOSPHERIC POLLEN RESEARCH AND CHALLENGES IN THE CONTEXT OF GLOBAL CHANGE. SESSION 2

### S.46.1 Vegetation and land-use distribution determine aerobiological risk areas in the Madrid Region

Jesús Rojo¹, Patricia Cervigón¹, Zuzana Ferencova², Ángel Cascón¹, Jorge Romero-Morte¹, Javier Galán Díaz³,¹, Silvia Sabariego⁴, Margarita Torres¹, Adela Montserrat Gutiérrez-Bustillo¹

¹Department of Pharmacology, Pharmacognosy and Botany, Faculty of Pharmacy, Complutense

University of Madrid, Madrid, Spain. 2 Atlantic Botanical Garden of Gijón, Gijón, Spain. 3 Department of Plant Biology and Ecology, University of Sevilla, Sevilla, Spain. 4 Department of Biodiversity, Ecology and Evolution, University Complutense of Madrid, Madrid, Spain

Pollen is the main source of outdoor aeroallergens, together with fungal spores, and because of allergic respiratory diseases depend on the seasonal occurrence of these aeroallergens, exacerbations of allergic symptoms follow a strongly seasonal pattern. Vegetation distribution and land-use configuration of the territory determine the occurrence and magnitude of pollen exposure, and then the airborne pollen spectrum. The aims of this study were to characterise the airborne pollen dynamics of aerobiological sampling
<figure><img src="image_120.png" /></figure>

stations of the Madrid Region Palynological Network in relation to the potential pollen sources and to define aerobiological risk areas of the Madrid Region based on homogeneous patterns of occurrence and intensity of the main pollen taxa. Multiple clustering approaches were conducted to group (i) the sampling stations of the aerobiological network and (ii) all pixels of the Madrid Region (central Spain). The clustering dendrogram based on vegetation distribution was compared to those based on airborne pollen characteristics. The results showed a great correspondence between potential pollen sources distribution and airborne pollen dynamics. The Madrid Region was divided into six aerobiological risk areas based on the potential pollen sources. These risk areas were ordered following a clear anthropogenic gradient, with one cluster in the centre covering the most urbanised areas, another one covering agricultural lands in the south and southeast, and four more clusters in the forest-dominated environments of the Madrid Region. Spatial regionalisation in environmental risk assessment favours the application of management plans by the institutions responsible of the management of public health systems and allows resources to be optimised. The mapping of risk areas based on impact of allergenic plant species constitute a step forward in the management of the biological air quality of Madrid Region.

## S.46.2 Effects of urbanisation on airborne pollen spectrum in cities

Marina Muñoz-García¹, Enrique de Gálvez-Montañez¹, Rocío Ruiz Mata¹, M. Mar Trigo, Marta Recio¹, Antonio Picornell¹

1 Department of Botany and Plant Physiology. University of Málaga, Malaga, Spain.

Climate change is affecting plant distribution, but human-driven land use changes are also playing a crucial role in it. Accelerated urbanisation drastically alters the landscape, generating a major impact on herbaceous plant communities in urban environments and, consequently, altering the airborne pollen concentrations in cities. Two of the most relevant impacts are vegetation removal for construction, as well as the introduction of ornamental species. The aim of this study is to analyze trends in the pollination period of herbaceous and ornamental species in the city of Málaga due to urban expansion. To do this, aerobiological data from the period 1992-2023 were used. The data were obtained by means of a Hirst-type volumetric pollen

sampler installed on the roof of the Faculty of Sciences of the University of Málaga. The samples were mounted and counted following the methodology proposed by the Spanish Aerobiology Network. The main pollen season (MPS) was defined by fitting a logarithmic function to the accumulated pollen concentrations. Then, trends in the parameters of the MPS were calculated employing linear regressions. The results reveal a significant decrease in the annual pollen integral of herbaceous taxa growing in agroforestry areas such as Amaranthaceae, *Plantago*, and *Rumex*, and a significant increase in pollen from nitrophilous species such as *Urtica membranacea*. *Olea* and *Platanus* pollen types have also increased their presence in the atmosphere due to the expansion of olive tree crops and the growth of ornamental individuals, respectively. The expansion of urban areas causes the loss of habitats as well as the modification of plant communities, which results in a modification of the air pollen content. Therefore, urban expansion can be involved in a significant change in seasonal allergies in the urban population.

## S.46.3 Implementation of the PhenoFlex framework for forecasting the start of the main pollen season in the context of climate change

Antonio Picornell¹, Enrique de Gálvez-Montañez¹, Marina Muñoz-García¹, Rocío Ruiz-Mata¹, Marta Recio¹, Eike Luedeling², M. Mar Trigo¹

1 Department of Botany and Plant Physiology. University of Málaga, Málaga, Spain. 2 Department of Horticultural Science, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Germany

Climate change is affecting the flowering seasonality of many plant species, disrupting the dynamics of their life cycles and triggering changes in ecosystems. These changes are not uniform across all species and geographic regions, and local monitoring is required to gauge future phenological shifts and to establish mitigation strategies. In this context, aerobiological sampling has proven to be a valuable tool for monitoring the flowering onset in anemophilous species. The start date of the main pollen season for a certain pollen type in a given location is usually linked to the flowering onset of the taxa that produce it. This has encouraged the development of different models in recent years to
<figure><img src="image_121.png" /></figure>

estimate the start of the main pollen season. However, some of these models rely on rigid assumptions that may not fit the diversity of the environmental conditions in which the plants grow. In 2021, Luedeling et al. developed the PhenoFlex statistical framework to forecast the flowering onset of tree species based on biological processes. This model accommodates for both overlapping and sequential chilling and forcing periods. It also fits all the model parameters for the targeted taxa, avoiding the arbitrary selection of fixed parameters. To date, this framework has not been used in aerobiological contexts. In this study, we delve into the applicability of this framework to aerobiological data and issue some recommendations for model validation and its use in estimating climate change impacts. As an example of application, PhenoFlex models were fitted to aerobiological data for Cupressaceae and *Platanus* from 8 sampling locations within Malaga Province (southern Spain) with 52 sampling years. The models registered mean absolute errors of 7.7 and 4.5 days, respectively, and were used to generate forecasts according to different future temperature scenarios.

iccating to the international genebank standard of 15-25% RH? If desiccation tolerant, 4) how does viability of previously desiccated then hermetically sealed pollen respond to freezing at conventional (-18°C) and -80°C temperatures? Finally, in order to understand relative storage lifespan and the influence of moisture relations, we asked, 5) How does pollen longevity respond to periods of time stored in varying RH environments. To answer these questions, we collected pollen from the National Tropical Botanical Garden's living collections. We desiccated pollen to a range of RHs at ambient temperature (-25°C), hermetically seal, and store at -18 and -80°C, then we tested viability via a germination test at each stage. To assess pollen longevity, survival curves were determined and compared using *p*₅₀ (the time for viability to decrease to 50%). Research into optimal pollen storage methods by species is needed to better understand the effects of desiccation, freezing, and time on pollen viability and longevity. Considering the current rate of plant extinction in Hawai'i, pollen storage is an important conservation tool for conducting controlled crosses that might otherwise not be possible.

### S.46.4 Pollen conservation of endangered Hawaiian endemic Hibiscus and Pritchardia species

Dustin Wolkis¹*, Natalie Blum², Makoa Elgin², Cecily Eltringham¹, Seana Walsh¹, Alina Wood¹

1 Department of Science and Conservation, National Tropical Botanical Garden, Kalāheo, USA.

2 School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA * corresponding author dwolkis@ntbg.org

Storage of pollen allows for gene exchange between geographically isolated individuals, and for controlled pollination when flowering of staminate and pistillate flowers or individual plants are asynchronous. Desiccation of pollen is essential for the retention of high longevity, yet research into pollen storage behavior is infrequently performed. *Hibiscus clayi* and *Pritchardia minor* are Kaua'i single island endemic plant species assessed as Critically Endangered and Endangered, respectively, by the IUCN Red List of Threatened Species. With respect to these species we asked; 1) How does pollen germination respond to varying sucrose concentrations (5-40%) and substrates (liquid/solid); 2) What is the pollen germination temperature niche breadth; 3) How does pollen viability respond after desiccating to the international genebank standard of 15-25% RH? If desiccation tolerant, 4) how does viability of previously desiccated then hermetically sealed pollen respond to freezing at conventional (-18°C) and -80°C temperatures? Finally, in order to understand relative storage lifespan and the influence of moisture relations, we asked, 5) How does pollen longevity respond to periods of time stored in varying RH environments. To answer these questions, we collected pollen from the National Tropical Botanical Garden's living collections. We desiccated pollen to a range of RHs at ambient temperature (-25°C), hermetically seal, and store at -18 and -80°C, then we tested viability via a germination test at each stage. To assess pollen longevity, survival curves were determined and compared using *p*₅₀ (the time for viability to decrease to 50%). Research into optimal pollen storage methods by species is needed to better understand the effects of desiccation, freezing, and time on pollen viability and longevity. Considering the current rate of plant extinction in Hawai'i, pollen storage is an important conservation tool for conducting controlled crosses that might otherwise not be possible.

### S.46.5 Aeropalinology, critical analysis of urban trees in cities with contrasting climates in Chile

Gloria I. Rojas¹

1 Museo Nacional de Historia Natural, Botanica, Santiago, Chile

The urbanization in Chile has brought the introduction of arboreal species to the inside of the cities, the same species are used in different type of Climate. For this reason it is desired to show that the trees used as ornamental in cities of our country has no relation to the phytogeographic and climatic zone in which they are inserted, and also in the case of Santiago is expected to demonstrate the effects on the health of people. Four cities of Chile are chosen to research it: Antofagasta, Santiago, Concepción and Valdivia, and from Spain, the city of Barcelona. An analysis of the native arboreal flora is performed and to know the species of the urban trees, the aeropalinological records of the cities involved are used. The results are subjected to the analysis of the Jaccard similarity index. For the case of Santiago, the relationship of the concentration of pollen in the air versus the pollen positive skin tests is given. It is concluded that the trees species of the studied cities are mainly exotic. There is a high degree of homogenization or similarity between the urban tree flora be-
<figure><img src="image_122.png" /></figure>

tween the cities of Chile and with Barcelona, the species are not related to its bioclimatic area, no native trees are used (if present is a fluke), we do not have original urban landscapes, and tree species in the case of Santiago are directly related to increases in pollen allergies.

## S.46.6 Guignardia bidwellii spores ecology in the vineyard, relation to weather factors and phenological development

María Fernández-González¹, Eva Navascués², Laura Montero², Dominique Roujou², Xose Manuel Lourido², Débora Franco³, José David Rey³, Kenia C. Sánchez Espinosa¹, Guillermo Guada¹, Lucía Carrera¹, F. Javier Rodríguez-Rajo¹

1 Department of Vegetal Biology and Soil Sciences, Faculty of Sciences, University of Vigo, Ourense, Spain. 2 Viña Meín-Emilio Rojo, Lugar de Meín, Leiro, Ourense, Spain. 3 Monet Tecnología e Innovación S.L., Nigrán, Pontevedra, Spain

Knowledge of the phenology and concentration of phytopathological fungi in a vineyard is a useful tool to estimate when a phytosanitary treatment is necessary, since today the high use of pesticides leads to subsequent soil contamination that can negatively affect the

soil biodiversity and the vine itself. Our aim was to understand how environmental conditions can influence the *Guignardia bidwellii*, causal agent of grape black rot. The study was carried out in two vineyards (Viña Mein and Emilio Rojo) belonging to the DO Ribeiro (Northwest Spain) during 2023 campaign. Phenological study was carried out on 20 selected vines following BBCH scale. To monitor the spores, two Lanzoni VPPS-2010 volumetric samplers are used, one in each study plot. The identification and counting of airborne spores have been carried out following the methodology proposed by the Spanish Aerobiology Network. Meteorological variables have been provided by two meteorological stations, located near the spore trap. The concentration of *G. bidwellii* spores was higher in Viña Mein (2912 spores) than in Emilio Rojo (656 spores). The peak of spore concentration occurred on May 28 with 438 spores/m³ in Viña Mein coinciding with the end of flowering stage (S-6), and 84 spores/m³ on June 23 in Emilio Rojo coinciding with fruit development stage (S-7). When analyzing intraday behavior of *G. bidwellii* spores in both plots, we observed that the highest concentrations occur at dawn (01:00-8:00 a.m.). The meteorological variables that exert the greatest influence on the concentration of *G. bidwellii* were the minimum temperature, dew point, relative humidity and precipitation. Knowledge of the phenological, phytopathological and meteorological variables of a certain region can provide us a valuable tool to know the phytosanitary status of a crop and thus be able to make appropriate decisions regarding the application of different phytosanitary treatments.

## S.47 INTEGRATIVE TAXONOMY OF MEDITERRANEAN PLANTS. SESSION 1

### S.47.1 Delimiting taxa boundaries in complex plant groups by genomic, morphometric, and ecological data: the case of Helianthemum

Sara Martín-Hernanz¹,², Abelardo Aparicio², Juan Viruel³, Björn Widén⁴, Polina Volkova⁵, Mohamed Djamel Miara⁶, Encarnación Rubio², Rafael G. Albaladejo²

1 Universidad Complutense de Madrid, Madrid, Spain. 2 Universidad de Sevilla, Sevilla, Spain. 3 Royal Botanic Gardens, Kew, Richmond, UK. 4 Lund University, Lund, Sweden. 5 Papanin Institute for Biology of Inland Waters RAS, Borok, Russia. 6 Ibn Khaldoun University of Tiaret, Tiaret, Algeria

The study of complex plant groups demands a comprehensive approach, encompassing macroevolutionary and microevolutionary scales. By integrating diverse data sources, we aim to offer a thorough perspective that aids in resolving taxonomic and systematic questions. Next Generation Sequencing technologies present a significant opportunity for unraveling the evolutionary processes within these challenging groups. Among these groups, the genus *Helianthe*-
<figure><img src="image_123.png" /></figure>

mum stands out as the most extensive genus within the Cistaceae family, boasting over 140 species and subspecies, included in 3 subgenera and 10 sections. Its distribution range extends from Macaronesia to Central Asia, covering North Africa and central Europe. Notably, *Helianthemum* exhibits one of the highest diversification rates in the Mediterranean Basin, attributed to three evolutionary radiations since the Pliocene. These radiations align with the three major sections: *Eriocarpum*, *Helianthemum*, and *Pseudocistus*, resulting in a complex taxonomy and nomenclature with poorly defined taxonomic boundaries. In our research, we employ an integrative approach that combine genomic techniques (GBS, target capture), ecological analyses (soil, climate), and morphological assessments (vegetative, floral, and karyological traits) at both macroevolutionary and microevolutionary levels. Our goal is to unravel the processes contributing to this taxonomic complexity and establish practical boundaries across all taxonomic ranks, from subgenera and sections to species and subspecies. Macroevolutionary findings indicate that higher taxonomic ranks (subgenera and sections) are generally well-defined in terms of phylogenetic, ecological, and morphological criteria. On the microevolutionary front, our investigation of polymorphic species within sect. *Pseudocistus* (*H. marifolium*, *H. cinereum*, and *H. oelandicum*) reveals compelling evidence of some introgression between them and the parallel evolution of characters previously used to define subspecies. This emphasizes the need for a synthetic taxonomic treatment with stable diagnostic characters at the lowest taxonomic levels.

## S.47.2 Integrative taxonomy of Centaurea aplolepa Moretti (Asteraceae) and related central Mediterranean species

Antonio Giacò¹, Andrea Coppi², Ludovica Fittipaldi², Mario Pentassuglia¹, Lorenzo Peruzzi¹

1 Department of biology, University of Pisa, Italy. 2 Department of biology, University of Firenze, Italy

*Centaurea* L., with approximately 600 species, is one of the largest genera of the Mediterranean Region. Due to this species richness and several biological phenomena (hybridization, introgression, polyploidy, etc...), the systematic and taxonomic investigation of this genus is highly challenging. In the central

Mediterranean, one of the groups still waiting for a thorough taxonomic revision is that of *C. aplolepa* Moretti. This species is endemic to north-western Italy and, during the last century, a great number of taxa at intraspecific rank was described. Currently, based on qualitative morphological and ecological (e.g., different growing substrate) observations, ten putative subspecies are accepted. Previous phylogenetic studies using ITS and the rpl chloroplast region failed to disentangle the relations within *C. aplolepa*. Indeed, its subspecies were all placed in an unresolved clade along with several other central Mediterranean morphologically related species. To understand the systematic relations among the subspecies of *C. aplolepa* and other closely related taxa, we started an integrated taxonomic investigation. During summer 2023, 17 populations of *C. aplolepa* and eight populations belonging to five related and geographically contiguous species were sampled. For each population, 30 individuals were collected for morphometric analyses. A subset of 15 individuals was used to extract DNA for population genetics using AFLP; cypselae were collected for cytotaxonomic studies (chromosome count and genome size estimation). The taxonomic investigation is currently ongoing, but preliminary morphometric results support the distinction of *C. aplolepa* with respect to the related species. Conversely, just three (instead of ten) morphological groups are supported within *C. aplolepa*.

## S.47.3 Integrative species delimitation in a Western Mediterranean polyploid complex

Salvatore Tomasello¹, Kamil Konowalik², Christoph Oberprieler³

1 Georg-August-University, Göttingen, Germany. 2 Wrocław University of Environmental and Life Sciences, Wrocław, Poland. 3 University of Regensburg, Regensburg, Germany

Species delimitation is particularly challenging in polyploid complexes pervaded by reticulate evolution. As allopolyploids are a mosaic of characters of their parental lineages, the simultaneous inference of the evolutionary history (allo- vs. auto-polyploidy) and delimitation of species is impracticable in those groups. For instance, the hybridogenic nature of allopolyploids violates the assumptions of the current DNA-based approaches for species delimitation. *Leucanthemopsis*
<figure><img src="image_124.png" /></figure>

(Giroux) Heywood is a genus of the Asteraceae, consist-
ing of six to ten species and several infraspecific taxa,
mainly distributed in the western Mediterranean Basin.
It is a polyploid complex that includes montane, subal-
pine, and strictly alpine lineages, which are locally dis-
tributed in different mountain ranges of Western Europe
and North Africa. We used a mixed approach including
Sanger sequencing and high throughput sequencing
of amplicons to gather information on single-copy nu-
clear markers and plastid regions. Nuclear regions were
carefully tested for recombinants/PCR artifacts and for
paralogy. Coalescent-based methods were used to
delimit species among the diploids. For the polyploids,
we first sorted homeologs of nuclear genes into pa-
rental subgenomes. Therefore, we inferred delimitation
among the Iberian tetraploids treating subgenomes
separately in the analyses. We corroborated results
from the DNA-based approaches with evidence from
morphometric analyses of leaf shapes and ecologi-
cal niche modelling. Based on the results, diploid taxa
found growing in the Eastern Iberian Peninsula con-
stitute a single, heterogeneous complex. Concerning
polyploids, the analyses inferred Iberian tetraploids as
having a clear allopolyploid origins. At least two differ-
ent polyploidization events gave rise to *L. spathulifo-
lia*, endemic of calcareous outcrops in South-eastern
Spain, on the one side, and to all other tetraploid Iberian
taxa on the other.

S.47.4 Integrative taxonomy
recircumscribes diversity of
the Dianthus sylvestris s.l. in
the Balkan Peninsula

Martina Temunović¹, Ana Terlević², Maja Mucko², Hirzi Luqman³, Alex Widmer⁴, Simone Fior⁴, Ivana Rešetnik²

1 Faculty of Forestry and Wood Technology, Univer-
sity of Zagreb, Zagreb, Croatia. 2 Faculty of Science,
University of Zagreb, Zagreb, Croatia. 3 McDonald
Institute for Archaeological Research, University of
Cambridge, Cambridge UK. 4 Institute for Integra-
tive Biology, ETH Zürich, Zürich, Switzerland

Dianthus is one of the most diverse plant genera in
the Mediterranean as a result of its rapid radiation in
this area. Dianthus sylvestris s.l. (Caryophyllaceae) is
a species complex distributed across southern and
south-eastern Europe and includes a large number
of taxa identified based on morphological characters.
Previous work has revealed that evolutionary lineages
within the complex are not reflected by the current tax-

onomy, as species boundaries are primarily determined
by past demographic events rather than by morpholo-
gy. Here, we focused on six currently described subspe-
cies distributed in the Balkan Peninsula and applied an
integrative approach combining population genomic
(RAD-seq), morphometric, genome size and environ-
mental data, to resolve the intraspecific relationships
and evolutionary history of the Balkan *D. sylvestris* pop-
ulations. Population structure revealed a strong diver-
gence of subsp. *tergestinus* from the rest of the Balkan
lineage. More detailed genetic variation patterns with-
in the Balkan lineage suggested two major groups of
populations which were largely concordant with the
two revealed morphological entities. The north-western
group included populations well-connected by gene
flow, formerly assigned to subsp. *sylvestris* and subsp.
*nodosus*. A south-eastern group included more isolat-
ed clusters of populations, formerly assigned to subsp.
*alboroseus*, subsp. *bertisceus* and subsp. *kozjakensis*.
Our combined results (genetic, morphometric, genome
size and environmental analyses) suggest survival of
the Pleistocene glaciations in two main glacial refugia
located along the eastern Adriatic coast, possibly fol-
lowed by secondary contact in the intermediate area.
However, we cannot exclude the existence of multiple
smaller microrefugia for the south-eastern group. Fi-
nally, our results do not support the current taxonomy.
Based on our integrative approach, we propose a spe-
cies-level treatment for the evolutionary distinct *D. terg-
estinus*, and the recircumscription of *D. sylvestris* subsp.
*sylvestris* and *D. sylvestris* subsp. *bertisceus* to corre-
spond to the north-western and south-eastern genetic
clusters, respectively.

S.47.5 Origin and
evolutionary dynamics
of the octoploid weed
Cardamine occulta and its
relatives

Terezie Mandáková¹, Judita Zozomová-
Lihová², Hiroshi Kudoh³, Yunpeng Zhao⁴,
Martin A. Lysak¹, and Karol Marhold²,⁵

1 Central European Institute of Technology, and
Faculty of Science, Masaryk University, Brno, Czech
Republic. 2 Plant Science and Biodiversity Centre,
Slovak Academy of Sciences, Bratislava, Slovak
Republic. 3 Center for Ecological Research, Kyo-
to University, Otsu, Japan. 4 The Key Laboratory of
Conservation Biology for Endangered Wildlife of the
Ministry of Education, College of Life Sciences, Zheji-
ang University, Hangzhou, China; Laboratory of Sys-
<figure><img src="image_125.png" /></figure>

tematic and Evolutionary Botany and Biodiversity, Institute of Ecology and Conservation Centre for Gene Resources of Endangered Wildlife, Zhejiang University, Hangzhou, China. 5 Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic

The genus *Cardamine* (Brassicaceae), encompassing over 200 species, exhibits a global distribution except of Antarctica. *C. occulta*, an octoploid (2n=64) weed indigenous to Eastern Asia, has become invasive after introductions to various continents, including Europe. In Europe this species first appeared in the Mediterranean region, particularly in Spain and in Italy (here due to rice cultivation near Torino). *C. occulta* shares its Eastern Asian habitat with related species such as the tetraploid (2n=32) *C. kokaiensis* and *C. scutata*, as well as the octoploid (2n=64) *C. dentipetala*. Genomic *in situ* hybridization and large-scale comparative chromosome painting were employed to elucidate the parental genomes and chromosome composition of these *Cardamine* species. All species trace their lineage to a common ancestral *Cardamine* genome (n=8), structurally resembling the Ancestral Crucifer Karyotype (n = 8) but differentiated by a translocation between chromosomes AK6 and AK8. The allotetraploid *C. scutata* resulted from hybridization between the diploids *C. parviflora* and *C. amara*. Conversely, *C. kokaiensis* has an autotetraploid origin related to *C. parviflora*. Notably, the octoploid *C. occulta* likely originated through hybridization between the tetraploids *C. scutata* and *C. kokaiensis*. The octoploid genome of *C. dentipetala* probably originated from *C. scutata* via autopolyploidization. Apart from a five species-specific centromere repositionings and one pericentric inversion post-dating polyploidization events, parental subgenomes remained stable in Asian tetra- and octoploids. Post-polyploid evolution in Asian *Cardamine* polyploids did not involve descending dysploidy or intergenomic rearrangements. The combination of diverse parental (sub)genomes adapted to distinct habitats conferred an evolutionary advantage to newly formed polyploids, allowing them to occupy new ecological niches. The revealed genomic insights into *Cardamine* polyploids not only enhance our understanding of their evolutionary history but also provide valuable knowledge for the targeted management of invasive species.

## S.47.6 Using functional traits in integrative taxonomy: the case of the Sonchus asper (L.) Hill (Asteraceae) complex in the Mediterranean

Pedro Costales-Maestre¹, Seung-Chul Kim², Marcial Escudero¹, José A. Mejías¹

1 Department of Plant Biology and Ecology, University of Seville, Spain. 2 Department of Biological Sciences, Sungkyunkwan University, Seobu-ro, Gang-Gu, Suwon, Korea

Functional traits are measurable properties of individuals that determine their basic performance model and role in the communities. The assignment of functional traits allows us to configure the ecological and evolutionary attributes of the individuals conforming a taxon and detect divergences associated to speciation processes. Furthermore, the analysis provides a framework for selecting appropriate operational criteria under the approach of Integrative Taxonomy. *Sonchus asper* (L.) Hill is a relevant case in this sense. It is considered a cosmopolitan self-fertilized annual weed with small, unattractive flower heads. However, the variability within the species' current circumscription revealed the presence of differentiated morphotypes in the Mediterranean, characterized by these functional traits: a) large flower heads, which denotes xenogamous sexual systems; and b) variability in growth habit, from the common annual cycle to creeping rhizomatous life form. A taxonomic revision under a multidisciplinary approach is consistently presented here. Morphologic examination revealed that flowers, leaves, underground parts and fruit traits are important to discriminate between morphotypes. Phylogenetic analysis revealed two separate clades: 1) autogamous with small flower heads; and 2) xenogamous with large flower heads, which includes three monophyletic and one paraphyletic groups. Chromosome number is conserved among morphotypes, with slight differences in chromosome morphology. Post-mating isolation barriers appear to be weak. Therefore, the analysis of ecological and distribution patterns is crucial to understand speciation processes. Our results support these conclusions: 1) The limitation of the name *S. asper* (L.) Hill to autogamous annual forms. 2) The reinstatement
<figure><img src="image_126.png" /></figure>

of three taxa described in the 19th-century: S. ny-
manii, a rhizomatous creeping Sicilian endemism;
S. glaucescens subsp. glaucescens, a biennial
south-eastern French coast endemism; and S.

glaucescens subsp. graecus, an annual widely
distributed throughout central and eastern Medi-
terranean. 3) The existence of a different perenni-
al taxon from mountainous areas of North Africa.

# S.48 BIOGEOGRAPHY AND DIVERSIFICATION OF INTERCONTINENTAL TROPICAL PLANT DIVERSITY. SESSION 3

S.48.1 Global patterns of phylogenetic and functional diversity of Scleria (Cyperaceae)

Javier Galán Díaz¹, Marcial Escudero²,
Isabel Larridon³,⁴

1 Universidad Complutense de Madrid, Spain. 2 Uni-
versidad de Sevilla, Spain. 3 Royal Botanic Gardens,
Kew, UK. 4 Meise Botanic Garden, Belgium

Scleria P.J.Bergius (1765: 142), commonly known as nut rushes or razor grasses, is the sixth largest genus in the Cyperaceae family with 261 species, and the only genus of tribe Sclerieae Wight & Arn. (subfamily Cyperoideae). Recent studies have disentangled the evolutionary relationships among Scleria species and identified major dispersal and niche shifts events. Here, we combined occurrence data, assessments of extinction risk, the latest phylogeny of the genus and trait data collected from herbarium specimens to: (i) explore the spatial distribution of Scleria phylogenetic and functional diversity facets, and (ii) identify species and world regions of remarkable interest for Scleria conservation. Central America, Western Africa, Madagascar and Northern Australia showed high functional and phylogenetic diversity. We also found that the four Scleria subgenera showed contrasting climatic niches, and clear functional segregation in terms of height, blade area and nutlet size. Scleria species from Africa and South America include a great diversity of functional types, whereas North America and Oceania are characterised by having shorter species with small leaves. Our results also suggest that around half of the species not yet included in the Red List of the IUCN are potentially threatened with extinction. We found 48 Evolutionary Distinct and Globally Endangered (EDGE) Scleria. Evolutionary and ecologically distinct and endangered Scleria mostly occur in a few African (Madagascar, Zambia, DR Con-

go and Tanzania) and South American (Brazil) regions.
Protecting these species, we would safeguard 68.47%
(41.07 MY) of avertable expected phylogenetic diversity
loss in the genus.

S.48.2 Did the drift of Hainan Island occur and affect the evolutionary trajectory of plants?

Pei-Han Huang<sup>1,2,6</sup>, Tian-Rui Wang<sup>2,3,6</sup>, Min Li<sup>1,6</sup>, Zi-Jia Lu<sup>2,5</sup>, Ren-Ping Su<sup>1,6</sup>, Ou-Yan Fang<sup>1,6</sup>, Lang Li<sup>1</sup>, Shi-Shun Zhou<sup>4</sup>, Yun-Hong Tan<sup>4</sup>, Hong-Hu Meng<sup>1,4</sup>, Yi-Gang Song<sup>2</sup>, Jie Li<sup>1</sup>

1 Plant Phylogenetics and Conservation Group, Center for Integrative Conservation & Yunnan Key Laboratory for Conservation of Tropical Rainforests and Asian Elephants, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China. 2 Eastern China Conservation Centre for Wild Endangered Plant Resources, Shanghai Chenshan Botanical Garden, Shanghai, China. 3 Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China. 4 Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences, Myanmar. 5 College of Life Sciences, Shanghai Normal University, Shanghai, China. 6 University of Chinese Academy of Sciences, Beijing, China

Demonstrating whether the plate-tectonic drifts of Hainan Island occurred and affected the evolutionary of plants will disentangle the issue puzzled natural scientists over decades. Here, *Engelhardia roxburghiana* around Hainan Island was selected to identify the genetic structure, diversity, and demographic dynamics using RAD-seq. Three lineages were identified, and the divergence time and genetic structure showed that *E. roxburghiana* dispersed from Chiang-nan to Hainan Island via land bridge during the late Eocene. Hence, drift
of Hainan Island did not occur, which was impossible to affect the evolutionary trajectory of plants. Higher genetic diversity in Yunnan-Guizhou Plateau and Chinese-nan Hilly Ranges are the results of mixed populations or refugia, while lower genetic diversity in the Indochina Peninsula due to historical bottleneck. During the late Eocene to Oligocene, the north shift of arid belt driven *E. roxburghiana* expand from Indochina Peninsula to southern China, and main diversification occurred in Miocene within the monsoon system. The climatic oscillations during Quaternary led to the expansion but there was slight contraction after LGM, while southern China was and will be the refugia to climate change. This is the first comprehensive work from large-scale SNP features, providing genomic insights into the geological history of Hainan Island from biogeographic patterns of *E. roxburghiana* it sheds light on geological history of Hainan Island and illuminates the biogeographic patterns of island-mainland in the regions.

## S.48.3 Plants on Malagasy inselbergs: exploring the hidden diversity of isolated populations

Juliane Rexroth¹, Christian Porsche¹, Marina Rabarimanarivo², Stefan Porembski¹

1 Department of Botany, Institute of Biosciences, University of Rostock, Germany. 2 Missouri Botanical Garden, Madagascar

Inselbergs are isolated, often monolithic rock outcrops, usually consisting of granite or gneiss. They are ecologically separated from the surrounding landscape and are thus referred to as terrestrial islands. Only relatively few plant species possess adaptive traits that enable them to grow successfully in inselberg habitats, characterised by a lack of soil and nutrients. As a typical floristic element of Malagasy inselbergs, the poikilohydric Velloziaceae can be highlighted. To explore the hidden genetic diversity of isolated populations of Malagasy Velloziaceae, which belong to the genus *Xerophyta*, we used microsatellite markers to assess the importance of geographic and ecological isolation on inselbergs as a trigger for speciation. Usually, species of the *Xerophyta* occur in isolated mats on open rocky slopes. Across all our samples, the analysed loci showed a high genetic diversity. Furthermore, almost all individuals had different multilocus genotypes, excluding clonality. Nevertheless, we were able to identify a few clones in our data. However, the emergence of clones is a relatively rare event.

Our previous studies have shown very low gene flow between individual inselbergs regardless of distance, favouring strong genetic and geographic differentiation. The morphological differences between plants from separated localities are probably the result of local adaptations and/or a consequence of phenotypic plasticity. In our analyses, we characterise the genetic diversity of a Malagasy *Xerophyta* species to contribute insights into evolutionary processes that may have led to the diversification of lineages of Malagasy inselberg species and to identify more vulnerable regions that require special conservation measures. Currently, Malagasy inselbergs suffer from human impacts (e.g. quarrying, fire), resulting in a dramatic decrease in the genetic diversity of taxa that consist of small isolated populations. It can be concluded that many spectacular taxa (incl. orchids, *Aloe* spp.) are facing similar problems concerning their long-term survival on Malagasy inselbergs.

## S.48.4 Multiple losses of structural color in the fruits of Elaeocarpus

Miranda Sinnott-Armstrong¹,², Silvia Vignolini²,³, Stacey D. Smith¹

1 Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO, USA. 2 Department of Chemistry, University of Cambridge, Cambridge, UK. 3 Sustainable Biomaterials, Max Planck Institute of Colloids and Interfaces, Golm, Potsdam, Germany

Most plants use pigments to color their flowers, fruits, and leaves, but structural colors are increasingly being described. In contrast to pigments, structural colors are nanostructures that interfere with light to create color. Due to the limited study of structural colors in plants, especially compared to their study in animals, our understanding of how and why structural colors evolve in plants is lacking. Here, we examine the evolution of structural color in *Elaeocarpus*, a tropical lineage with the first described structurally colored fruit. We confirm that *E. angustifolius* has a multilayered structure, but we find that the structure is made of lipids rather than of polysaccharides (as was previously described). The use of lipids to build a multilayer reflector is similar to that of recently described species (*Viburnum tinus* and *Lantana strigocamara*), although the type of lipid is different. Furthermore, anatomically, the structure in *Elaeocarpus* differs in that it occurs in the extracellular space, rather than embedded in the cell wall as in *Viburnum* and *Lantana*. These anatomical
<figure><img src="image_127.png" /></figure>

and chemical differences indicate that the structure in *Elaeocarpus* has very different evolutionary origins to similar structures described previously. Additionally, we observe that all blue-fruited species in *Elaeocarpus* exhibit the same type of structure, and that the structure was lost multiple times in black-, brown-, yellow-, and red-fruited species. This is the first time that losses of structural color have been documented in plants and suggests that the energetic investment in building large structures out of lipids may not always be advantageous in fruits.

## S.48.5 General dynamic model of oceanic island biogeography predicts early diversification dynamics of a highly successful insular plant

Jay Edneil C. Olivar¹, Frank Hauenschild¹,⁴, Hannah J. Atkins², Gemma L.C. Bramley³, Alexandra N. Muellner-Riehl¹,⁵

1 Department of Molecular Evolution and Plant Systematics & Herbarium (LZ), Institute of Biology, Leipzig University, Leipzig, Germany. 2 Royal Botanic Garden Edinburgh, UK. 3 Royal Botanic Gardens Kew, Richmond, Surrey, UK. 4 Centre for Teacher Training and School Research, Leipzig University, Leipzig, Germany. 5 German Centre for Integrative Biodiversity Research, Halle-Jena-Leipzig, Leipzig, Germany

The general dynamic model of oceanic island biogeography (GDM) views oceanic islands predominantly as sinks rather than sources of dispersing lineages. To test this, we conducted a biogeographic analysis of a highly successful insular plant taxon, *Cyrtandra*, and inferred directionality of dispersal and founder events throughout the four biogeographical units of the Indo-Australian Archipelago (IAA), namely Sunda, Wallacea, Philippines, and Sahul. Sunda was recovered as the major source area, followed by Wallacea. The relatively high number of dispersal and founder events originating from Wallacea is attributed to its central location in the IAA and its complex geological history selecting for increased dispersibility in *Cyrtandra*. We also tested if early diversification dynamics in *Cyrtandra* follow predictions of adaptive radiation, which is the dominant process on oceanic islands as per the GDM. Diversification dynamics of dispersing lineages of *Cyrtandra* in the Southeast Asian grade showed early bursts in diversification rates followed by a plateau which is consistent with adaptive radiation. We did not detect signals of diversity-dependent diversification, and this is attributed to Southeast Asian cyrtandras occupying various niche spaces as evident by its wide morphological range, particularly in habit and floral characters. The clade containing mostly Pacific members, which arrived at the early stages of the ontogeny of the Pacific Islands, showed diversification dynamics predicted by the Island Immaturity Speciation Pulse (IISP) model and their morphological range is controlled by the least action effect favoring woodiness and fleshy fruits. Our study provides a first step towards a framework for investigating early diversification dynamics as predicted by GDM in highly successful insular taxa.

## S.49 NEW FRONTIERS IN PLANT PHYLOGENOMICS. SESSION 3

### S.49.1 Helpful or deceiving? Reference genomes and their influence on phylogenetic tree topologies.

Christoph Nehrke¹, Mareike Daubert¹, Eike Mayland-Quellhorst¹, Dirk C. Albach¹

1 Carl-von-Ossietzky University Oldenburg, Oldenburg, Germany

Recent improvements in genome sequencing, especially long read sequencing techniques like Oxford Nanopore sequencing, provide the means to assemble high quality (draft) genomes for a plethora of species. While these genomes find uses in multiple fields of life sciences, a common application for them is to serve as references in the assembly of high-throughput sequencing reads in phylogenomics. However, it is unclear how quality and phylogenetic position of a reference relative to the investigated dataset influence phylogenomic assemblies and topology of phylogenetic trees. To answer this question, we sequenced and assembled genomes
<figure><img src="image_128.png" /></figure>

of seven species of Veronica, a plant genus known for polyploidization, frequent hybridization and high speciation rates, using Oxford Nanopore sequencing in combination with high coverage Illumina sequencing reads. The assembled references were tested for quality, completeness, contiguity, and possible contaminants. A Genotyping-by-sequencing dataset including 72 samples from Veronica subg. Pseudolysimachium was assembled denovo, as well as reference-assisted with different parameters, using each draft genome as a reference. We found that not only alignment lengths and number of retrieved loci are changing among the different reference genomes, but also tree topologies and branch lengths, depending on reference taxon and reference quality. These variable results may lead to false conclusions regarding the evolutionary history of the subgenus.

## S.49.2 Maximizing the Phylogenetic Yield of Low-Coverage Shotgun Sequencing and Target-Enrichment in Plants Through New Bioinformatic Tools

Charles Pouchon¹,²

1 Conservatory and Botanical Garden of Geneva, Chambèsy-Geneva, Switzerland .2 Department of Plant sciences, University of Geneva, Geneva, Switzerland

Low-coverage shotgun sequencing is a fast and cost-effective method that has been widely used in plants to infer phylogenies mostly from organelle genomes. However, obtaining such data with common organelle assemblers, can be particularly challenging in some plant families with complex genomic structures and rearrangements. In addition, the shallow coverage of the nuclear genome associated with these libraries (<3 x) prevents the use of nuclear sequences, leading recently to an increased use of target-enrichment methods in phylogenomic studies. In this context, we developed ORTHOSKIM, a universal and versatile bioinformatic pipeline that allows targeting both organelle and nuclear data in shotgun libraries (enriched or not), with reference sequences and specific modes accounting for paralogous issues as those expected with organelle gene transfers. Nuclear references are however not

always available in non-model organisms, and organelle sequences only represent around 10% of the shotgun libraries when not enriched. This results in a tremendous waste of sequencing data. To make use of the 90% remaining data, we also developed REFMAKER that uses a blind approach to create specific sets of nuclear loci, which can be extracted directly from the low coverage libraries (<3 x). These two methods can be jointly used in the same phylogenetic framework to exploit all the produced reads, regardless of their sequencing depth.

## S.49.3 Strategies to improve alignment accuracy in large-scale plant phylogenomic analyses

Michael Gruenstaeud¹

1 Department of Biological Sciences, Fort Hays State University, Kansas, USA

Despite the large quantities of nucleotide sequences that are analyzed in contemporary plant phylogenomics, the process of multiple sequence alignment (MSA) remains one of its central tenets. Any phylogenomic investigation will only be as reliable as the positional homology established among its underlying sequences, irrespective of their length, genomic origin, or taxonomic representation. Diversifying or further increasing the amount of input sequences is not a substitute for careful and often time-expensive MSA. Instead, the ever-larger data volumes in plant phylogenomics highlight the demand for analysis workflows that accommodate the complexities of nucleotide sequence evolution, especially at the microstructural level. In this presentation, I argue that despite the skyrocketing amounts of sequence data in contemporary plant phylogenomics, the associated MSA process must not be dismissed as a cumbersome side aspect. Specifically, I highlight that while the existing toolkit of MSA software appears sufficiently diverse to tackle the challenges of large-scale plant phylogenomics, their integration into phylogenomic analysis pipelines awaits substantial improvement, especially when accounting for genome-specific idiosyncracies and microstructural mutations. Several empirical examples are presented to support these observations. First, I demonstrate that the correct assessment of positional homology in genome-level sequence data can significantly improve plastid phylogenomic reconstructions in a lineage of South American sunflowers. Second, I
<figure><img src="image_129.png" /></figure>

illustrate that the manual post-processing of software-generated MSAs significantly improves the reliability of phylogenomic reconstructions among water lilies and that such post-processing can be achieved with reasonable effort even for phylogenomic data. Third, I introduce a software tool that enables the automatic separation of genome sequence data into natural partitions - genes, introns, and intergenic spacers - across thousands of input genomes and automates their individual MSA for different software tools. Based on these results, I highlight the need for an increased effort to develop targeted and customized MSA strategies for plant phylogenomics.

**S.49.4 Tracing the phylogenomic roots: revisiting evolution and biogeography in the Tribe Maleae of the Rosaceae Family**

R. Ufimov¹,³, S. Píšová², T. Fér⁴, C. Dobeš¹, M. van Loo¹, R. Schmick|⁴,⁵

1 Institute of Forest Growth, Silviculture, and Genetics, Austrian Research Centre for Forests, Vienna, Austria. 2 Institute of Forest Biodiversity and Nature Conservation, Austrian Research Centre for Forests, Vienna, Austria. 3 Komarov Botanical Institute, Russian Academy of Sciences, St. Petersburg, Russian Federation. 4 Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic. 5 Institute of Botany, The Czech Academy of Sciences, Průhonice, Czech Republic

The Rosaceae tribe Maleae, encompassing a wide range of fruit crops, horticultural, and forestry species, displays significant diversity, especially within its subtribe, Malinae. This study undertook a comprehensive Hyb-Seq-based nuclear and plastid phylogenetic analysis of 184 accessions from 159 species across all genera within Maleae. The objective was to place the evolutionary trajectory of Maleae in both a spatial and temporal framework, while also investigating the potential drivers of diversification in Malinae, particularly focusing on the role of whole genome duplication (WGD). The research uncovered two major radiative events within the Malinae subtribe. The first of these events occurred around the Early Eocene in the Madrean Region, and the second during the Middle Miocene in East Asia. These evolutionary radiations were shaped by over 50 million

years of changing habitat connectivity, involving the Madrean-Tethyan floristic belt and the Boreotropical forest belt. The patterns of diversity within this plant group were significantly influenced by a series of environmental factors, including habitat disjunction, vicariance, and long-distance dispersal events. A key finding of the study was the impact of WGD at the inception of Maleae evolution. The retention of gene copies post-WGD demonstrated a strong phylogenetic signal, suggesting a pivotal role in the diversification process. Representing the most extensive taxon sampling undertaken to date, the study sheds light on the complex biogeographic history of Maleae. It also reveals evidence of genus-specific diploidization following WGD, highlighting the intricate evolutionary dynamics within this significant plant group.

**S.49.5 Phylogenomics and evolution of recently diverged and closely related species: a case study in Rosa sect. Synstylae (Rosaceae)**

Ji-Hyeon Jeon¹, Masayuki Maki², Yu-Chung Chiang³, Younhee Shin⁴, and Seung-Chul Kim¹

1 Department of Biological Sciences, Sungkyunkwan University, Suwon, Republic of Korea. 2 Department of Ecological Developmental Adaptability Life Sciences, Tohoku University, Sendai, Japan. 3 Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan. 4 Research and Development Center, Insilicogen Inc., Yongin, Republic of Korea

Many phylogenetic or evolutionary studies across various plant taxa, particularly those involving recently diverged and closely related species, have historically faced challenges in comprehending species relationships and evolutionary histories within these groups. Recent advancements in genome-wide sequencing technologies and bioinformatics tools have now empowered phylogenomic analyses to unravel robust species phylogenies, offering valuable insights into the intricate evolutionary trajectories of lineages characterized by complex histories. The East Asian wild roses within Rosa section Synstylae (Rosaceae), recognized as significant genetic contributors to modern ornamental roses, represent a group of species known
to have recently diverged and maintained close relationships. Leveraging 1,683 highly conserved single-copy orthologs from the reference genome of *R. chinensis*, a close relative within the *Synstylae* section, we successfully established the first robust phylogenetic relationships among eight species in *Rosa* section *Synstylae*. Moreover, additional phylogenomic analyses unveiled the complex evolutionary history of the *R. sect*. *Synstylae* lineage, likely influenced by a combination of deep coalescence and genetic introgressions. Through comparative

ortholog analyses utilizing the draft genome assembly of *R. lucieae*, we discerned patterns of gene family evolution within section *Synstylae*, particularly in response to the adaptation to specific ecological niches. These innovative phylogenomic approaches not only enhance our understanding of the evolution of East Asian wild roses but also offer a framework for comprehending the evolutionary dynamics of other recently diverged and closely related lineages worldwide.

# S.50 INTEGRATING CONSERVATION BIOLOGY AND SOCIETY ENGAGEMENT TO ENHANCE PROTECTION OF AT RISK FLORA. SESSION 2

## S.50.1 Experiential learning is vital for Plant Conservation

Rajesh Rajaselvam¹

1 Department of Biology, Dalhousie University, Halifax, Canada

Being a part of nature adds new dimensions to our perception of it. Experiential learning enhances this perception by providing real-world experiences that help formulate ideal conservation strategies. With the clock of extinction ticking fast, the message on conservation must reach the younger generation swiftly. Admiration arises from experiencing something good; thus, visits to gardens and wilderness areas serve as inspirational platforms for practical education in botany, landscaping, and the conservation of plants and nature. School outreach activities and undergraduate field courses in experiential learning not only bolster conservation efforts but also facilitate the exchange of ideas on genuine conservation practices. Exploring Sri Lankan national parks from Canada through multiple educational field trips enabled students to grasp global concerns and promote awareness, paving the way for making biodiversity conservation in the tropics a reality. My experiential learning field courses have led me to conclude that garden and field visits, hands-on activities in the field, and the commitment of resource personnel are key elements in motivating young generations toward plant and biodiversity conservation.

## S.50.2 Plant conservation strategies of the Ministry for Ecological Transition and Demographic Challenge (Spain)

Noelia Vallejo Pedregal¹, Marta Viu Cuerda¹

1 General Subdirectorate of Terrestrial and Marine Biodiversity, Ministry for Ecological Transition and Demographic Challenge, Spain

The Spanish Ministry for Ecological Transition and Demographic Challenge (MTRD) is responsible for planning, formulation of strategies, and establishment of fundamental guidelines for the conservation and sustainable use of natural heritage and biodiversity, in accordance with national and international regulations. Plant species constitute an essential component of biodiversity, and face numerous threats stemming from human activities. Spain, as a country with a high level of endemism, has a significant responsibility for their conservation. In this context, the main working lines of MTRD are: a) Monitoring the conservation status of all protected species, as well as the status, distribution, and trends of invasive alien species; b) Developing strategies for conservation and fight against the main threats to protected plants; c) Launching the Networks of Forestry and Wild Flora Germplasm Bank as tools
<figure><img src="image_130.png" /></figure>

for ex situ conservation; d) Carrying field tests for the conservation measures applied to protected species; e) Coordinating plant conservation efforts with regional administrations; f) Updating catalogues of protected and invasive species; and g) Coordinating conservation measures addressed to the critically endangered plant Cistus heterophyllus subsp. carthaginensis.

### S.50.3 Threatened plant species in agroecosystems: is the coexistence between nature conservation and productivity feasible?

Anna Corli¹,², Simone Orsenigo¹,², Thomas Abeli²,³, Fiona Jane White¹, Micol Orengo¹, Margherita Tognela¹, Martina D'Agostino³, Graziano Rossi¹

1 Department of Earth and Environmental Sciences, University of Pavia, Pavia, Italy. 2 National Biodiversity Future Center, Palermo, Italy. 3 Department of Science, Roma Tre University, Rome, Italy

Agricultural practices are among the most significant threats to plant diversity worldwide. Many threatened species strictly linked to agroecosystems have already disappeared from agricultural areas, particularly in more intensively farmed countries such as in Europe. The recovery of species listed in the Habitat Directive 92/43/CEE, the main legal conservation framework in the EU, is mandatory. However, the reintroduction of threatened species to agroecosystems is constrained by difficulties in recolonizing the original habitat after extirpation. Where populations do avoid destruction, they remain confined to relict habitats which are highly fragmented within an agricultural landscape (on farm). There has been a paradigm shift in conservation to restore biodiversity not only in natural habitats but also in semi-natural areas deemed worthy of conservation. Organic and conventional farms with low-input practices have been suggested as having a potentially biodiversity-friendly approach to farming. The increased demand of food from sustainable sources, especially from organic agriculture, has led to improved environmental conditions and consequently assisted in species conservation. However, for nature conservation and agricultural productivity to co-exist, the needs of stakeholders must

be considered. These include concerns with detrimental effects on crop yields, a perception of focal species as potential weeds, legal constraints for species protection, and increased costs associated with conservation. However, there are several benefits to farmers of biodiversity conservation in agroecosystems such as *ad hoc* financial incentives (e.g., from the EU Rural Development Plan), improved ecosystem services provisioning, and opportunities for marketing sustainable products. We discuss the implications and limitations of biodiversity conservation in agroecosystems using examples from Europe of the threatened species *Marsilea quadrifolia*, *Isoëtes malinverniana*, *Lindernia procumbens*, *Bromus interruptus*, *B. gros sus*, *Agrostemma githago* and *Centaurea cyanus*.

### S.50.4 Rapid assessments accurately predict increased extinction risk of megafire impacted flora

Tom Le Breton¹, Mark Ooi¹, Sylvia Hay¹, Tony Auld¹

1 Centre for Ecosystem Science, University of New South Wales, Australia

The combined pressures of global climate change and anthropogenic disturbance of the natural world are leading to a rapid rise in the number of species at risk of extinction. For many taxa, these numbers are rising faster than it is currently possible to keep track of leading to an increased need to utilise rapid assessments to accelerate extinction risk assessments and ensure plant species receive timely conservation actions. The 2019-2020 Black Summer fires had extensive impacts on native flora necessitating a prioritisation process to identify the species most in need of rapid and full extinction risk assessments. We used a tiered approach to identify priority species for full extinction risk assessments and compared how well rapid assessments with minimal information predicted extinction risk after full assessment. Some 400 species received rapid assessments and 135 received full assessments. The rapid assessments accurately predicted the final threat status of 59% of species. Higher threat statuses like Critically Endangered and Endangered where more accurately predicted than Vulnerable and Not Threatened. Of the 135 species that received full assessments 85%
were found to be at greater risk of extinction following the fires, Our results highlight the value of rapid assessments in response to these landmark disasters with widespread impacts as well as for accelerating comprehensive listings of under assessed flora.

## S.50.5 The vision of plant conservation in Europe along the strategies and recommendations

Erika P. Kónya¹

1 Department of Botany and Plant Physiology, Eszterházy Kátoly Catholic University, Eger, Hungary

In last decades it became clear that urgent activities are needed in plant conservation. The area and connectivity of habitats and species will be very important to analyse the direction and intensity of threats of rare species. Although there are new strategies for protecting native species, the scale of the drivers of extinction can be variable and in several cases we don't know the small scale drivers of the life history traits of plant species. Sometimes new ways are needed for checking the feature of species selected for revision and recommendations for example according to the new, accepted strategic plan of Bern Convention between 2023 and 2030. A review and a survey can help member states and experts to analyze the real processes and in characterizing the state of plant species living in Pan-European areas. Different scale has been used and a general, good working conservation methodology have been elaborated together with organizations. The target of making the strategic plan more objective is the multiscale revision of plant species in Annex I. The first step is to determine the main risks in distribution and life history of the species which can be asked through a questionnaire tool. The mutualistic features, seed ecology and the life span also very important factors of protection and restoration success. In connection with the sustainable use of plant species we must take into account the annual or short lived species and their population stability through their interactions in natural habitats.

## S.50.6 Conservation of rare arable species through the study of their competitive relationships with crops in the agroecosystem

Martina D'Agostino¹, Silvia Assolari², Francesco Boscutti³,⁴, Giacomo Trotta³,⁵, Marco Vuerich³, Thomas Abeli¹

1 Roma Tre University, Rome, Italy. 2 SemeNostrum, Udine, Italy. 3 University of Udine, Udine, Italy. 4 National Biodiversity Future Center, Palermo, Italy. 5 University of Trieste, Trieste, Italy

After 1950, wild arable plants (hereafter arable species) underwent a dramatic decline due to the rapid intensification of agriculture. In most cases, arable species are considered as weeds and, for this reason, they have been systematically eradicated in conventional farming systems. Arable species extirpated even in sustainable agricultural systems are no longer able to recolonize their former range. Therefore, the reintroduction of arable species within agroecosystems has been proposed to improve their conservation status. Unfortunately, farmers are often reluctant to accept the reintroduction of endangered plants to their lands, as they could reduce crop productivity through competition. Therefore, it is important to understand if farmers' fears of a reduction of crop productivity are grounded in evidence, to engage them to promote coexistence between crops and rare arable species. We studied the mutual competitive effects between two iconic arable species, Agrostemma githago L. and Centaurea cyanus L., and wheat (Triticum aestivum L., variety Palesio) in two densities (5% and 10%) in an open field experiment at the SemeNostrum company (Udine, Italy) in 2022/2023. Analysing the roots/shoots ratio, A. githago and C. cyanus in competition with the crop significantly reduced the aerial part growth in relation to the root part. The arable species-crop interaction also affected the specific leaf area and chlorophyll content of wild species, which decreased in the presence of wheat. For T. aestivum, instead, there was no significant effect on the biomass, specific leaf area or chlorophyll content due to the presence of A. githago and C. cyanus. Results were consistent in both densities. This first comparative analysis evidences a plausible model of coexistence of arable species and crops. This will provide the baseline for future translocation protocols of threatened species in agricultural contexts.
# S.51 FLORAL SPECIALIZATION AND THE GENERALISED NATURE OF POLLINATION INTERACTIONS. SESSION 3

## S.51.1 Actinomorphy to Zygomorphy: bilateral symmetry, with correct flower orientation, greatly increases pollen transfer

Nathan Muchhala¹

1 Biology Department, University of Missouri - St. Louis, USA

While the ancestral symmetry of angiosperm flowers is actinomorphic (radial symmetry), hundreds of lineages have independently evolved zygomorphic flowers (bilateral symmetry). Such shifts are associated with more specialized pollination systems, and lead to significant increases in diversification rates. But what are the actual benefits of zygomorphic flowers for a plant? One little-tested assumption is that zygomorphy maximizes pollen transfer by allowing flowers to place pollen in a more precise and repeatable way on pollinator's bodies. This is supported by the fact that floral orientation tends to be more consistent, and often can be quickly re-adjusted, for zygomorphic flowers compared to actinomorphic ones. In this study, we performed flight cage experiments with nectar-feeding bats and artificial flowers, testing how floral symmetry and orientation affect pollen removal and transfer. For each flower, four anthers were placed either all of the way around the opening (actinomorphic) or together at one side of the opening (zygomorphic). Nearly twice as much pollen was transferred between zygomorphic flowers, but only when angled at 45°, causing pollen to be consistently placed on the tops of bats' heads. When flowers were positioned flat (i.e., facing upwards), bats approached from many different angles, and zygomorphic flowers performed no better than actinomorphic ones in terms of pollen transfer. Thus, results suggest that shifts to zygomorphy allow more specialized pollination systems which, with the correct floral orientation, maximize pollen transfer success.

## S.51.2 The effect of grooming on plant reproduction: a theoretical approach

Vanessa G. Marcelo¹,³*, Flávia M.D. Marquitti², Mario Vallejo-Marín³, Vinicius L.G. Brito¹

1 Universidade Federal de Uberlândia, Uberlândia, Brazil. 2 Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, Campinas, Brazil. 3 Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden. *email- vanessa.marcello@ebc.uu.se

The pathway to male reproductive success in plants is affected by events that potentially affect the chance of individual pollen grains reaching the stigma, such as grooming behavior by pollen vectors and the variation in the positioning of reproductive organs. To date, only a few theoretical investigations have attempted to model the effect of grooming on pollen transfer, and empirical studies have been limited to species in which pollen movement can be tracked. Thus, we use a spatially explicit agent-based modeling (ABMs) approach to determine the effect of pollen redistribution and removal in the "pollen landscape" on the vector body, affecting plant reproductive success and mating between floral individuals, associated with variation in reproductive organs. For this, we simulated pollen vector visits and their grooming behavior on a sequence of different flowers in a population. We showed that pollen redistribution and removal restructure the pollen landscape in the body of the bee, in a way that increases the pollen delivery in consecutive visits and the number of pollen donors deposited on the stigmas. We also observed that the mating networks were affected both by the grooming behavior and by the morphological variation of the reproductive organs. So, in the absence of grooming, together with the variation in the positioning of the stigma, makes populations more connected and generalist. The grooming behavior breaks the dominance of some individuals, making the relationships between individuals better distributed. Floral individ-
<figure><img src="image_131.png" /></figure>

uals visited by vectors without grooming and that have variation in stigma position are reproductively more generalists. Our model predicts that species pollinated by non-grooming vectors are more variable in stigma position than species pollinated by grooming vector. However, empirical studies will be needed to confirm the predictions we generate with our model, allowing greater knowledge of the factors that may affect pollen transfer.

### S.51.3 Does cheating pay off? Influence of floral traits on pollinator behavior and plant fitness in a food-deceptive European orchid

Noa L.A. Schwabe¹, Bentje Bossert², Ingo Grass², Philipp M. Schlüter¹

1 Department of Plant Evolutionary Biology, Institute of Biology, University of Hohenheim, Stuttgart, Germany. 2 Department of Ecology of Tropical Agricultural Systems, Institute of Agricultural Sciences in the Tropics, University of Hohenheim, Stuttgart, Germany

In food-deceptive pollination systems, plants attract pollinators without offering any reward. The plant lures the insect into pollination by showing traits similar to rewarding flowers. Our research aims to comprehensively understand the pollination ecology within a food-deceptive system (*Orchis militaris*) and to identify key traits influencing pollinator attraction, spatial heterogeneity, pollination success, and consequently, plant fitness. Furthermore, we are investigating the avoidance behavior of pollinators in this deceptive system. We are studying two distinct populations, both located north of the Alps, approximately 650 km apart, covering the broad habitat requirements of *O. militaris*. By identifying effective pollinators of *O. militaris*, along with their co-vegetation, our preliminary results indicate marked differences between the two populations, highlighting a broad pollinator spectrum. The overall pollination success and seed set was high. Main pollinators are Hymenoptera (Apidae), ranging from large (*Apis mellifera*) to small (*Lasioglossum marginatum*). While pollinator abundance appears to be directly linked to plant fitness, current observations indicate that the density of deceptive orchids does not adversely affect pollination success. Notably, we observed that bees seemingly do not exhibit avoidance behavior even in high-density deceptive or-

chid populations. These preliminary results contradict the hypothesis that pollinators learn deceptive strategies, and therefore show avoidance behavior. As a next step, we aim to understand the mechanisms underlying this observation. To examine the learning process of pollinators, specifically whether they avoid specific floral traits (color) or areas after encountering non-rewarding plants, we are planning to mark bees in the field and to conduct choice experiments with *A. mellifera*. In summary, our study provides insights into pollination ecology and the associated pollinator behavior contributing to the evolution of deceptive systems, which is also of relevance for habitat conservation and management strategies in times of rapid biodiversity declines.

### S.51.4 Equal access opportunity: heterospecific pollen tubes grow in the styles of close- and distantly-related species

Rachel O. Cohen¹, Deren A.R. Eaton¹

1 Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, USA

In plant communities where generalist pollinators are shared, the likelihood of heterospecific pollen transfer (HPT) increases, potentially affecting female reproductive success. This scenario may drive evolutionary adaptations aimed at either minimizing the occurrence of HPT (pre-pollination) or reducing its impact (post-pollination). While it is commonly assumed that post-pollination mechanisms restrict heterospecific pollen tube growth in the stigma or early in the style, direct measurements of this process are relatively infrequent. When heterospecific pollen tube growth is assessed, studies often focus on intrageneric exchanges, even though plants in diverse communities and may exchange pollen with both close and distant relatives. To explore the impact of HPT in a diverse plant community, we performed experimental crosses involving co-flowering, non-hybridizing plants across a spectrum of genetic distance from an alpine plant community at Rocky Mountain Biological Laboratory (Colorado, USA). Using semi-in vivo pollen tube assays, fluorescence microscopy, and ovary size measurements, we examined pollen tube growth and ovary size change following all-by-all reciprocal crosses with 11 species (representatives from Orobanchaceae, Lamiaceae,
<figure><img src="image_132.png" /></figure>

Phrymaceae, Linaceae, and Fabaceae). Contrary to expectations that pollen tube growth is more likely among closely related species and rare among distant relatives, we observed consistent pollen tube growth among all species pairs, ranging from conspecifics to those in different plant orders. Generalized linear models revealed no significant effects of genetic distance on the probability of pollen tube growth through the stigma and into the style. These results suggest that in plants with close ecological interactions, reproductive barriers to reproduction may not broadly include suspension of heterospecific pollen tubes within the stigma and style. Instead, pre-pollination barriers, differences in pollen tube growth rates, and post-zygotic barriers likely play more significant roles.

## S.51.5 Multifaceted strategies ensure prezygotic reproductive isolation of coexisting species of Stenospermation (Araceae)

Natalia Castaño-Rubiano¹,², Luna Ibáñez², Eliana Álvarez-Valdez², Melisa Alegría Valencia¹, Luis Alberto Núñez-Avellaneda³, Gonzalo Taborda-Ocampo², Alejandro Zuluaga-Trochez¹, Artur Campos Dalia Maia⁴,⁵

1 Universidad del Valle, Cali, Colombia. 2 Universidad de Caldas, Manizales, Colombia. 3 Universidad de La Salle, Bogotá, Colombia. 4 Université of Corsica, Ajaccio, France. 5 Universidade Federal de Pernambuco, Recife, Brazil

Plants reliance on external agents for pollination has led to significant adaptations in floral traits, potentially contributing to the remarkable species diversity observed in this group. Reproductive isolation mechanisms between populations, particularly pre- and post-zygotic isolation in congeneric and sympatric species, play a critical role in minimizing competition for pollinators. Reproductive strategies, including flowering time, visual signals, floral fragrance chemistry, and rewards offered, facilitate coexistence and can act as prezygotic reproductive isolation barriers when gene flow persists, allowing for hybrid formation. We investigated the reproductive systems, isolation mechanisms, and pollination dynamics of coexisting species of *Stenospermation* (Araceae) in two lo-

calities of Colombia's central and western Andes. We assessed pollen transfer and the potential for hybrid formation using pollination and hybridization tests. Additionally, we evaluated the effectiveness of phenological and ethological isolation in preventing self-pollination. Floral volatile compounds were analyzed using Dynamic Headspace and GC-MS techniques, and attractiveness assays were performed to determine pollinator preferences. *Stenospermation* exhibits a sexual system with androgynous flowers, and protogyny prevents self-pollination, precluding fruit production through apomixis. Our results demonstrate the possibility of hybridization through controlled experiments. *Stenospermation* communities exhibited low synchronicity or were asynchronous. All species display varying anthesis hours and share their floral volatile chemistry and pollinators at various degrees. We conclude that *Stenospermation* employs a multi-factorial approach to prezygotic isolation involving ethological, phenological, and ecological factors, as no single trait thoroughly explains the observed isolation. Pollinator facilitation between syntopic species and complementary life cycles with pollinators contribute to reproductive success. Spathe tissue, the floral chamber and the thermogenesis are crucial floral rewards, particularly for large pollinators like *Cyclocephala*.

## S.51.6 Improving flowers to help feed the world: bee responses to field-realistic floral trait variation in strawberry

Hamish Symington¹, Beverley Glover¹

1 Department of Plant Sciences, University of Cambridge, UK

A rising global population will need more food, increasing demand for insect pollination services. However, general insect declines conflict with this demand. One way to mitigate this conflict is to grow crop flowers that are easier for insects to find, and more rewarding to those that visit them. Our work quantifies variation in the pollinator-relevant traits of nectar and pollen production, flower size and flower shape in commercial strawberry, finding significant variation between varieties in all traits. Bumblebees could learn to distinguish between the extremes of variation in flower shape, but this learning is very
slow, indicating that this variation is at the limit of
that which can be detected by bumblebees. Bee
preferences for nectar of differing sugar concentra-
tions at field-realistic volumes were consistent with
previous observations at larger volumes, suggesting

that it is valid to translate lab findings to the field. Our
findings build on our knowledge of the range of pol-
linator reward present in a single cultivated species,
and of the impact of field-realistic levels of variation
in floral traits on bumblebee preferences.

S.52 AFRICAN TAXONOMY: A COLLABORATIVE
EFFORT TOWARDS BIODIVERSITY
CONSERVATION. SESSION 2

S.52.1 A taxonomically-
vetted checklist shows that
species richness of Nigerian
plants is underrepresented
in major floristic databases

Abubakar Bello¹,²,³, Martin Cheek⁴, Iain
Darbyshire⁴, George Gosline⁴, Gwilym
Lewis⁴, Thomas L.P. Couvreur⁵, Alan
Paton⁴, Isabel Larridon⁴, Fatima Batul
Mukhtar⁶, Suzanne Mogue⁴, Carmen
Puglisi⁴, Jean Michel Onana⁷, Ana
Rita Simoes⁴, David Harris⁸, Alejandro
Quintanar⁹, Xander van der Burgt⁴, Olivier
Lachenaud¹⁰, Bente Klitgård⁴, David
Goyder⁴, A. Muthama Muasya¹¹, Samaila
Samaila Yaradua³, Maria S. Vorontsova⁴,
Anifat O. Bello¹², Daniel A. Zhigila¹³, Marco
Schmidt¹⁴, Bruce Murphy⁴, Christian
Wirth¹², Carsten Meyer², Aletta Bonn²,
Christine Fürst², Hazel M. Chapman¹⁵,
George I. Nodza¹⁶, Oluwatoyin Ogundipe¹⁶,
Alexandra N. Muellner-Riehl¹,²

1 Leipzig University, Leipzig, Germany. 2 German Centre for Integrative Biodiversity Research, Halle-Jena-Leipzig, Leipzig, Germany. 3 Umaru Musa Yaradua University, Katsina, Nigeria. 4 Royal Botanic Gardens, Kew, Herbarium, UK. 5 DIADE, Univ Montpellier, CIRAD, IRD, Montpellier, France. 6 Bayero University Kano, Kano State, Nigeria. 7 University of Yaoundé I, Yaoundé, Cameroon. 8 Royal Botanic Garden Edinburgh, Edinburgh, UK. 9 Royal Botanical Garden of Madrid, Madrid, Spain. 10 Université Libre de Bruxelles, Bruxelles, Belgium. 11 University of Cape Town, Cape Town, South Africa. 12 University of Wit-

watersrand, Johannesburg, South Africa. 13 Gombe
State University, Gombe, Nigeria. 14 Palmengarten
und Botanischer Garten Frankfurt, Frankfurt/Main,
Germany. 15 University of Canterbury, Christchurch,
New Zealand. 16 University of Lagos, Lagos, Nigeria

"Beyond Extrapolations: A Taxonomically-Vetted Checklist of Nigeria's Vascular Plants" is a new initiative shedding light on the gross underrepresentation of Nigeria's plant diversity in major global floristic databases. Current estimates of Nigeria's plant diversity rely heavily on out-of-date extrapolations from the Flora of West Tropical Africa, a publication now six decades old. In response to this critical gap, our consortium is spearheading an ambitious effort to compile a comprehensive, taxonomically-verified, and vouchered checklist of all vascular plants in Nigeria. This presentation unveils the significant findings of our research, emphasizing the disparity between existing global databases and the true botanical richness of Nigeria. We present the second and third outputs in a series of publications stemming from this pioneering effort. Using the historical trend of botanical explorations, we demonstrate that there are still many new plant species to be discovered in Nigeria. To achieve a comprehensive description of these new plant species, a significant number of taxonomists will be needed for an extended period. This demonstrates the significance of capacity building as a milestone in implementing the Global Biodiversity Framework (GBF). It is an urgent priority to find and name these remaining undiscovered species, Red List them, and allocate resources to protect those in need. Recent research has shown that 77% of new plant species at the point of publication today are threatened with extinction. This endeavor serves not only as an update on our progress, but also as a call to action to rectify the prevailing underrepresentation. We offer insights into the challenges faced, methodologies employed, and the significance of our ongoing efforts in advancing
<figure><img src="image_133.png" /></figure>

botanical research in Nigeria. Our work establishes a robust foundation for understanding Nigeria's plant diversity, paving the way for enhanced conservation efforts, sustainable development, and a more comprehensive global understanding of the country's botanical wealth.

**S.52.2 Synergy of taxonomy and environmental monitoring, an approach to biodiversity conservation: A case study in Ghana.**

Peter Atta-Adjei Junior¹, Allotey Albert Nii Moe², Seyram Kumordzi¹, Yaw Appau¹, Portia Seble Elorm¹, Akuamoa-Boateng Michael¹ and Tonny Asafo-Agyei¹

1 Centre for Plant Medicine Research, Mampong Akuapem, Ghana. 2 Institute for Scientific & Technological Information, Council for Scientific & Industrial Research, Accra, Ghana.

The phenomenon of spatio-temporal dynamics occurs as a significant component of environmental monitoring in the 21st century. It deploys sophisticated tools such as satellites and advanced computer applications. Taxonomists believe correctly identifying biological species promotes a universally focused activity such as conservation. Following frequent visits to some portions of the Accra plains of Ghana for plant collection activities, it was observed that some areas and plants are speedily depleted. This concern motivated an investigation at the Shai-Osudoku district occurring on the Accra plains to ascertain the extent of depletion and understand the potential losses and consequences. The Shai-Osudoku district which is enriched with a wide range of medicinal plant species spanning from forest to savannah species was studied to ascertain the rate of land use/landcover change over the past two decades. Using mango plantations as a model, a survey was conducted to verify the spatio-temporal dynamics of mango farming in the Shai-Osudoku district. Images were downloaded from the internet (United States Geological Survey/Global Land Cover Facility) to cross-check survey results. The survey data were analyzed using IBM SPSS 20 and images downloaded were classified using first, ISODATA algorithm with 25 classes and later knowledge-based supervised classification. The results indicated that land use/land cover change has occurred.

Also, areas of 'waterbody' and 'mango plantation' increased by 35.62% and 72.14% respectively as 'vegetation' and 'built-up' decreased by 35.20% and 39.55%. Farmers agreed their standard of living improved at the advent of mango production and the market value of mango remained unchanged by Spatio-temporal dynamics but were ignorant about the long-term economic effects of their activities on the increasing depletion population of medicinal plants. Further verification was done using satellite images in comparison with herbarium data to ascertain the erosion of some medicinal plant species from their collection locations.

**S.52.3 Conservation of plant diversity in East Africa**

Qingfeng Wang¹,²

1 Wuhan Botanical Garden, Chinese Academy of Sciences, China. 2 Sino-Africa Joint Research Center, Chinese Academy of Sciences, China

East Africa is home to more than 30,000 species of plants, yet current data reveals significant gaps in floral surveys and studies, with about 16% of the region having zero collections and about 50% being under-surveyed. In the context of China-Africa scientific and technological collaboration under the "One Belt, One Road" initiative, the scientists from China and East African countries have engaged in extensive collaborative researches, focusing on plant taxonomy and conservation biology. For instance, the *Flora of Kenya*, a collaborative project initiated by scientists from China and Kenya. The team carried out studies on numerous pre-surveyed weak areas and discovered more than ten new taxa. These efforts further facilitated the understanding of the diversity of the Kenyan flora as well as its distribution pattern. In Rwanda, the collaborative team discovered more natural populations of dwarf Rwandan water lily (*Nymphaea thermarum*). A comprehensive taxonomic morphology description was undertaken, and active involvement in its conservation efforts ensued. In Madagascar, the conservation genomic studies of baobabs were performed incorporating with in-depth ecological analyses which further raise the concerns on efficient protection of these amazing trees on the island. All these findings and results would provide valuable insights for developing effective and biologically informed conservation strategies for the biodiversity of East Africa in a changing world.
<figure><img src="image_134.png" /></figure>

## S.52.4 Exorcising the demons: subtribal revision of the ironweed tribe (Vernonieae, Compositae) in the Eastern Hemisphere.

Morgan R. Gostel¹, M. Andotiana Andriamanohera¹, Higor Antonio-Domingues², Ana R.G. Simões², Isabel Larridon², Benoit Loeuille²

1 Botanical Research Institute of Texas, Fort Worth, Texas, USA. 2 Royal Botanic Gardens, Kew, Richmond, UK

The ironweed tribe, Vernonieae, is one of the most species rich in the daisy family (Compositae) and has a complicated taxonomic history that has led to it being referred to by a number of pejoratives, including the “evil tribe.” A key challenge for taxonomists who work with this tribe was the recognition of a large and poorly defined core genus, Vernonia, which included more than 1,000 species worldwide. In 1999, the genus was re-circumscribed to comprise just 20 species from the Americas and as a result, the necessary reclassification of more than 1,000 species in Vernonia sensu lato was initiated. In the last two decades, significant systematic efforts have resulted in the reclassification of many Vernonieae taxa in the Western Hemisphere. However, comparably little progress has been made toward taxonomic revision of the genus in the Eastern Hemisphere, where ca. 700 species are recognized from West Africa to Southeast Asia and the Pacific islands. Throughout the range of this tribe in the Eastern Hemisphere, there are currently 13 subtribes and 67 genera, but approximately 150 species in this tribe remain in Vernonia and await reclassification. Furthermore, recent studies suggest few of the subtribes currently recognized are monophyletic. We present results of phylogenomic analyses using a combined marker set including Angiosperms353 and Compositae-1061 as well as a greatly expanded sampling of species in this tribe from the Eastern Hemisphere to test the monophyly of subtribes and genera. We also explore morphological character variation in the tribe to understand patterns of evolution and help to support sub-tribal identification of taxa in the field and collections. Lastly, we present a plan to curate and rapidly share taxonomic data using the Global Compositae Database.

## S.52.5 Floristic diversity, carbon stocks and degradation factors in two sacred forests in the West Cameroon Region.

Maffo M. N. Liliane¹, Mounmemi K. Hubert¹, Mbaire M. K. Marx¹, Zapfack Louis¹

1 Department of Plant Biology, University of Yaoundé, Yaoundé, Cameroon

Sacred forests play a valuable role in conserving local biodiversity and provide numerous ecosystem services in Cameroon. The study was carried out in the sacred forests of Bandrefam and Batoufam (western Cameroon). The aim was to estimate the diversity of woody species, carbon stocks and degradation factors in these sacred forests. The floristic inventory was carried out in plots measuring 25 × 25 m for trees with diameters greater than 10 cm, and 5 × 5 m for trees with diameters less than 10 cm. Carbon stocks were estimated using the non-destructive method and the allometric equations of Fayolle et al. (2018), Chave et al. (2014) and Ntomen (2020). Data on degradation factors were collected using semi-structured surveys in the Bandrefam and Batoufam neighbourhoods. The floristic inventory identified 65 species divided into 57 genera and 30 families in the Bandrefam sacred forest, and 45 species divided into 42 genera and 27 families in the Batoufam sacred forest. The families common to both sacred forests are as follows: Phyllanthaceae, Fabaceae, Moraceae, Lamiaceae, Malvaceae, Rubiaceae, Meliaceae, Anacardiaceae, Sapindaceae. Three genera are present in both sites. These are: Albizia, Macaranga, Trichillia. In addition, there are 27 species in common between the two sites. The total carbon stock is 469.26 tC/ha at Batoufam and 291.41 tC/ha at Bandrefam. The economic value varies between 15 823 877.05 fcfa at Batoufam and 9 825 530.528 fcfa at Bandrefam. The study shows that despite the sacred nature of these forests, they are subject to degradation factors such as bush fires (35.42 %), the creation of plantations (23.96 %), illegal timber exploitation (21.88 %), young people's lack of interest in the notion of conservation (9.38 %), climate change (7.29 %) and growing urbanisation (2.08 %). These factors threaten biodiversity and reduce carbon storage in these forests.
# S.52 EVOLUTIONARY ECOLOGY OF PLANTS.
## SESSION 3

### S.53.1 The ecology and biogeography of spiny plants

Kyle W. Tomlinson¹, Tristan Charles-Dominique²,³, Artemis Anést³, Theodore Lefébvre¹, Mohammed Armani⁴, Uriel Gélin⁵

1 Center for Integrative Conservation & Yunnan Key Laboratory for Conservation of Tropical Rainforests and Asian Elephants, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yunnan, China. 2 Centre National de la Recherche Scientifique (CNRS), Sorbonne University, Paris, France. 3 AMAP, Univ Montpellier, CIRAD, CNRS, INRAE, IRD, Montpellier, France. 4 Dept of Ecology and Evolutionary Biology, Yale Univ, New Haven, CT, USA. 5 Centre for Biodiversity Dynamics in a Changing World (BIOCHANGE), Section of Ecoinformatics and Biodiversity, Department of Biology, Aarhus University, Aarhus, Denmark

Spines are a major ecological innovation supporting plant defence and diversification, present in over 10% of woody plant species. Spine anatomy is diverse, having arisen in multiple plant lineages from many different plant organs and parts of organs, which may be differ in relative advantaged across environmental gradients. We have tried to make sense of this diversity, by address the following core questions. 1. Do spiny plants possess functional trait syndromes that distinguish them from non-spiny plants, and are there differences between spines with different anatomies (spine types)? 2. Where are spines found in environmental space and are there differences between different spine types? 3. What is the evolutionary history of spiny plants? I discuss our ongoing inferences about these topics and future directions we pursue. In brief, our analyses show that different spine types have different functional traits and differ in their distribution across climate and possibly soil gradients. Spines appear to have evolved in response to the evolution of particular mammal lineages on each continent, and that pre-adaptation appears to have been a fundamental part of their diversification in new continents. These combined results emphasise the importance of plant

defensive architecture for the spatial distribution of plant diversity, and the substantive role of extinct mammals in structuring modern plant diversity.

### S.53.2 Elucidating trait evolution in forest tree species in response to recent climate changes: a review

José Alberto Ramírez-Valiente¹,², Antoine Kremer³

1 Institute of Forest Science, INIA-CSIC, Madrid, Spain. 2 CREAF, Barcelona, Spain. 3 BIOGECO, INRAE, Bordeaux, France

One of the main questions in evolutionary biology is whether populations can evolve in response to the ongoing climate change. Understanding past evolutionary trajectories might help us to predict present and future responses. In this review, we aim to identify the main climatic drivers of selection, to detect key traits for adaptation to climate heterogeneity and evaluate the evolutionary potential of forest tree species in response to contemporary climate change. Results from phenotypic selection studies at different temporal and spatial scales report that leaf traits, particularly those related to morphology and physiology are under significant selection. Consistently, a meta-analysis on common garden experiments showed widespread population divergence across species in growth, phenology, leaf economics and allometry. Associations with climate, however, strongly differed across biomes. In general, temperature is the main driver of population divergence in temperate environments whereas precipitation is the main driver in seasonally-dry tropical ecosystems. In Mediterranean environments, both temperature and precipitation have had important roles in population evolution but acting on different traits. Specifically, whereas phenology and growth have evolved in response to minimum temperatures in winter, leaf morphology and leaf economics have evolved in response to precipitation. Studies combining phenotypic and genomic data
<figure><img src="image_135.png" /></figure>

show that estimated ancestral populations tend to exhibit more conservative resource-use strategies which would provide evidence of adaptation to a colder environment in the past. Synchronic studies also support the existence of evolutionary responses to contemporary climate changes (less than 500 years) in growth, phenology and leaf physiology consistent with population studies and phenotypic selection analyses. Overall, our results suggest high evolutionary potential in forest tree species that has allowed them to respond recent climate fluctua tions. However, further studies are needed to eluci date the pace of evolution, particularly through mul tivariate perspectives that assess trait integration within phenotypes.

### S.53.3 Trait evolution reveals fire-prone ecosystems at the origin of the Mediterranean climate: a case study on Juniperus oxycedrus L.

David Gutiérrez-Larruscain¹, Pablo Vargas², Mario Fernández-Mazuecos³, Juli G. Pausas⁴

1 Desertification Research Centre (CIDE: CSIC-UV-GVA), Valencia, Spain. 2 Real Jardín Botánico (CSIC), Madrid, Spain. 3 Universidad Autónoma de Madrid, Madrid, Spain.

The Mediterranean climate is known for its summer droughts, resulting in recurrent fires as the primary form of disturbance. With the onset of this climate, newly fire-prone ecosystems emerged, stimulating species diversification and triggering strong selection for traits that enable persistence in response to fire. One such adaptive trait is post-fire resprouting, facilitated by the belowground location of meristematic tissues. *Juniperus oxycedrus*, a gymnosperm species belonging to the cypress family and distributed across the western Mediterranean basin, is reported as the only species within *Juniperus* section *Juniperus* capable of resprouting after a fire. This study evaluated the resprouting capability of *J. oxycedrus* through the examination of 22 burned areas across the Iberian Peninsula. Surprisingly, individuals identified as *J. oxycedrus* subsp. *badia* were not able to re-sprout. Genotyping-by-Sequencing (GBS), a reduction-representation genome strategy, was employed on 11-12 individuals from each examined population.

The objectives were to (1) evaluate the genetic diversity within each lineage and population, (2) examine gene flow levels between lineages and, (3) date the split of the *J. oxycedrus* resprouting lineage.

### S.53.4 Amphistomy increases leaf photosynthesis more in coastal than montane plants of Hawaiian 'ilima (Sida fallax)

Genevieve Triplett¹, Thomas N. Buckley², Christopher D. Muir¹,³

1 School of Life Sciences, University of Hawai'i Mānoa, Honolulu, HI, USA. 2 Department of Plant Sciences, University of California, Davis, CA, USA. 3 Department of Botany, University of Wisconsin, Madison, WI, USA

The adaptive significance of stomata on both upper and lower leaf surfaces, called amphistomy, is unresolved. A widespread association between amphistomy and open, sunny habitats suggests the adaptive benefit of amphistomy may be greatest in these contexts, but this hypothesis has not been tested experimentally. Understanding why amphistomy evolves can inform its potential as a target for crop improvement and paleoenvironment reconstruction. We developed a new method to quantify "amphistomy advantage", AA, as the log-ratio of photosynthesis in an amphistomatous leaf to that of the same leaf but with gas exchange blocked through the upper (adaxial) surface, which we term "pseudohypostomy". We used humidity to modulate stomatal conductance and thus compare photosynthetic rates at the same total stomatal conductance. We estimated AA and related physiological and anatomical traits in 12 populations, six coastal (open, sunny) and six montane (closed, shaded), of the indigenous Hawaiian species *Ilima* (*Sida fallax*). Coastal *Ilima* leaves benefit 4.04 times more from amphistomy compared to their montane counterparts. Our evidence was equivocal with respect to two hypotheses – that coastal leaves benefit more because 1) they are thicker and therefore have lower CO₂ conductance through the internal airspace, and 2) that they benefit more because they have similar conductance on each surface, as opposed to most of the conductance being on the lower (abaxial) surface. This is the first direct experimental evidence
<figure><img src="image_136.png" /></figure>

that amphistomy *per se* increases photosynthesis, consistent with the hypothesis that parallel pathways through upper and lower mesophyll increase the supply of CO₂ to chloroplasts. The prevalence of amphistomatous leaves in open, sunny habitats can partially be explained the increased benefit of amphistomy in 'sun' leaves, but the mechanistic basis of this observation is an area for future research.

### S.53.5 Systematic, evolutionary, and ecological perspectives on the repeated convergent evolution of mimetic seeds in legumes

Benjamin M. Torke¹, Luísa M. de P. A. Bezerra², Domingos Cardoso³, Kuo-fang Chung⁴, Ana Paula Fortuna Pérez⁵, Mohammad Vatanparast⁶

1 New York Botanical Garden, Institute of Systematic Botany, Bronx, NY, USA. 2 Universidade Estadual Paulista, Botucatu, São Paulo, Brazil. 3 Coordenação Flora e Funga do Brasil, Jardim Botânico do Rio de Janeiro, Rio de Janeiro, Brazil. 4 Museum Biodiversity Research Center, Academia Sinica, Taipei, Taiwan. 5 Universidade Estadual Paulista, Botucatu, São Paulo, Brazil. 6 Jodrell Laboratory, Royal Botanic Gardens, Kew, UK

Seeds that deceptively mimic nutritious fruits or arillate seeds but provide no nutritive rewards to dispersers have evolved repeatedly in Fabaceae and are one of the most striking examples of phenotypic convergence in the family, yet their evolutionary origins have been little studied. These seeds are associated with a suite of traits, including bright coloration, extreme hardness and impermeability, strong physical dormancy, suppressed abscission, and accumulation of toxic secondary metabolites, that define a parasitic dispersal syndrome targeting naive frugivorous birds. To attract sufficient numbers of dispersers, this strategy requires that seeds remain attached to dehisced pods in the plant canopy for long periods of time, increasing risk of deterioration and exposure to predators. We review the biology of mimetic seeds in the context of the increasingly well resolved phylogeny of legumes and present preliminary data relevant to hypotheses about their origins. We conclude that mimetic seeds have arisen convergently at least 16 times in the family, but only in subfamilies Caesalpinioideae and Faboideae. In most cases the

evolutionary transition to parasitism is associated with an abrupt shift to bird dispersal from some other dispersal mode involving one or more non-avian dispersal agents; apparent transitions from mutualistic to parasitic bird dispersal are few. Evolutionary origins of several of the characteristic traits of mimetic seeds—hardness, location in persistent fruits, and toxic secondary metabolites—predate transitions to bird dispersal and mimicry; these traits were likely exapted for their current functions in mimetic seeds. Two other traits—bright coloration and suppressed abscission—are much more closely associated with transitions to mimicry and bird dispersal, and thus likely constitute original adaptations for these purposes. Planned comparative studies on the genetic control of this latter class of traits may be illuminating with respect to the apparent propensity for lineages of Fabaceae to evolve mimetic seeds.

### S.53.6 Where mating is overrated: Understanding the evolution and ecology of asexual reproduction in a tropical understory herb

Ritu Yadav¹, Vinita Gowda²

1 Tropical Ecology and Evolution Lab, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh, India. 2 Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh, India

Flowering plants have a diversity of mechanisms for reproduction. Both asexual and sexual modes represent alternative reproductive mechanisms that plants may adopt in order to counter temporally or spatially variable environments. In plants, it is common to find that a single individual may resort to either mode, resulting in a "mixed reproductive strategy." Our study is focused on the genus *Globba* L., which is a tropical understory herb. It is known for its high diversity in reproductive strategies, with presence of both sexual (andromonecy) and asexual (bulbils) modes of reproduction. The objective of our study is to investigate ecological factors that may have shaped the evolution of bulbils in *Globba*, and to show how this strategy may have helped the genus diversify in the Asian tropical understory. We specifically address the evolutionary significance of asexual reproduction and how it is an efficient reproductive strategy. To study the evolution of bulbils in this genus, we sampled Indian *Globba* spp. from the states of Northeast India and Western Ghats and used sequences from NCBI for the
remaining species. A Bayesian phylogenetic analysis using BEAST was carried out on nuclear and chloroplast data set with 89 species. To study the ecological and physiological relevance of asexual reproduction in *Globba*, we also carried out field experiments for 10 species across 15 populations. Our results suggest that the presence of bulbils is an ancestral state and may have evolved multiple times in the genus *Globba*. We

also identified obligate asexual taxa differed in their ecological characteristics (such as population size, pollinator visitation rate, natural fruit set, and physiological compatibility). The disproportionate distributional success of obligate asexual species suggested that asexual reproduction by bulbils is clearly an advantageous and an efficient reproductive strategy in some *Globba* species.

# S.54 EVOLUTION OF PLANT SEXUAL REPRODUCTION. SESSION 1

## S.54.1 Deducing the ancestor of angiosperms from the timeline of molecular evolutionary events associated with flower-specific traits

Léa Rambaud-Lavigne¹, Marie Morel², Bastien Boussau², Raquel Tavares³, Eva Álvarez Medrano⁴, José Manuel Franco Zorrilla⁴, Richard Bateman⁵, Paula Rudall⁵, Niels Jacobsen⁶, Pierre Chambrier¹, Charlie Scutt¹

1 Ecole Normale Supérieure de Lyon, France. 2 Université Claude-Bernard, Lyon, France. 3 BIOPOLIS/ CIBIO-InBIO, Vairão Portugal. 4 Centro Nacional de Biotecnología, Madrid, Spain. 5 Royal Botanic Gardens-Kew, London, UK. 6 University of Copenhagen, Denmark. Contact: charlie.scutt@ens-lyon.fr

The angiosperms, also known as flowering plants, contain numerous traits that are absent from their molecular-phylogenetically identified sister group, the living gymnosperms. Such angiosperm-specific traits include the outer integument of the ovule, the carpel, the perianth, and the bisexual reproductive axis. The extinct gymnosperm orders Caytoniales and Bennetitales have been suggested as strong candidates for ancestors or close stem relatives of angiosperms, but these possess contrasting sets of angiosperm-like features. In Caytoniales, the ovules are enclosed within a cupule, which might (or might not) represent a precursor to either the carpel or the outer integument of angiosperms. In Bennetitales, by contrast, there is no cupule, but a perianth-like structure and a bisexual axis (in some taxa) are present. We are analyzing

the evolution of gene lineages that control the development of, or are specifically expressed in, the above-listed angiosperm-specific features. Our aim is to deduce the order of potential neo-functionalization events in these lineages and hence the likely order-of-origin of the traits/organs with which they are associated. In particular, the *epsilon* whole genome duplication, which preceded the radiation of living angiosperms, provides a useful genome-wide time-point to separate earlier and later evolutionary events along the angiosperm stem lineage. The proposition that the outer integument of the angiosperm ovule arose from a Caytoniales-type cupule has been particularly prominent in recent literature, which emphasizes the curved symmetry found in both the cupule and the anatropous angiosperm ovule. A part of our project accordingly focusses on the molecular mechanism of ovule curvature and its degree of conservation between model and early diverging angiosperms.

## S.54.2 The role of polyploidy for the evolution of sexual and apomictic reproductive systems in angiosperms

Elvira Hörandl¹, Claudia Paetzold¹,², Birthe H. Barke¹, Fuad Bahrul Ulum¹,³, Ladislav Hodač¹,⁴, Eleni Syngelaki¹

1 Department of Systematics, Biodiversity and Evolution of Plants (with herbarium), University of Goettingen, Germany. 2 Department of Botany and Molecular Evolution, Senckenberg Research Institute, Frankfurt am Main, Germany. 3 Biology Department, Mathematic and Sciences Faculty, Jember University, Jember, Indonesia. 4 Max Planck Institute for Biogeochemistry, Department Biogeochemical Integration, Jena, Germany
<figure><img src="image_137.png" /></figure>

The predominance of sexual reproduction in eukaryotes despite high costs is still an evolutionary enigma. Major theories propose that sex could provide a two-fold DNA restoration tool, i.e. repair of oxidative damage during meiosis, and selective elimination of harmful mutations via recombination. In angiosperms only about 2.3% of genera and <1% of species reproduce via apomixis (i.e., reproduction via asexually formed seeds). Most natural apomicts are polyploids, but the reasons for this association remain still unclear. Previous hypotheses suggested that genome duplication would be the functional trigger for apomixis by altering gene expression and epigenetic control. However, several studies indicate that apomixis already starts in diploid populations at low frequencies and can be inherited by haploid gametes. Transcriptomics on diploid aposporous F2 hybrids suggest that a "lucky combination" of mutations in genes related to reproductive development could be a functional trigger of apomeiosis. However, polyploidy has indirect positive effects to establish apomictic lineages. First, polyploidy can lower abiotic stress, e.g., light stress, which will reduce the trigger of oxidative stress for initiation of meiosis, thereby favouring facultative asexual pathways. Second, polyploidy can buffer short-term effects of recessive deleterious mutations, and only a little bit of facultative recombination (6%) is efficient to for purifying selection even in big polyploid genomes. Third, polyploidy can facilitate niche shifts by adaptations to more extreme environments by epigenetic changes and phenotypic plasticity, which will be demonstrated by DNA methylation and gene expression analysis. Fourth, polyploidy results in a breakdown of self-compatibility, which allows for self-fertilization and uni-parental reproduction in pseudogamous apomicts, which is an advantage for colonization. Experimental and molecular work on *Ranunculus* supports these hypotheses. We conclude that hybridity rather than polyploidy is the primary functional trigger for apomixis, but polyploidy is essential for establishment of apomictic lineages in natural populations.

## S.54.3 Anther development and evolution with single-cell RNA-sequencing

D. Blaine Marchant¹,²

1 Department of Biology, Stanford University, Stanford, California, USA. 2 Department of Biology, University of Missouri - St. Louis, St. Louis, Missouri, USA

The anther is the developmental housing of pollen of flowering plants. The meiotic cells from which pollen

are derived must differentiate de novo from somatic anther cells and synchronously develop with the rest of the anther. Understanding the genes that underlie the proper differentiation, developmental landmarks, and functions of each anther cell type is fundamental to plant sciences. Here, we investigated the development of the somatic niche of the maize (Zea mays) anther using single-cell RNA-seq (scRNA-seq). We established the developmental trajectories of the somatic cell types from pre-meiosis to post-meiosis, identified putative marker genes for the cell types that previously lacked any known specific functions, and addressed the possibility that tapetal cells sequentially redifferentiate. Finally, we compared these results with anther scRNA-seq data from wheat (Triticum turgidum) to assess the evolutionary conservation of anther development. These results are essential for future analyses investigating male-sterile genotypes and the impact of environmental conditions on male fertility in flowering plants.

## S.54.4 The role of LEUNIG and SEUSS transcriptional regulators during land plant evolution

Julian V. Garrecht¹, Julian Ingelfinger², Annette Becker¹

¹Institute of Botany, Justus-Liebig University Gießen, Giessen, Germany. ²Technical University of Kaiserslautern, Kaiserslautern, Germany

The adaptation of reproductive strategies to the terrestrial environment was one of the crucial steps of the transition from water to land that plants had to overcome. During land plant evolution, various adaptations emerged, from the simple, water-dependent fertilization mechanism of bryophytes to the morphologically highly diverse flowers of angiosperms. This wide range of reproductive strategies makes it especially noteworthy that some of the essential regulators of flower development in angiosperms are present in all major land plant lineages. In *Arabidopsis thaliana*, the transcriptional regulators LEUNIG (LUG) and SEUSS (SEU) play an important role in flower development: LUG and SEU first form a heterodimer, which then can interact with floral organ identity proteins such as APETALAI, and other developmental regulators such as AINTEGUMENTA. The moss *Physcomitrium patens* encodes, like *Arabidopsis*, several homologs of LUG and SEU, raising the questions of (1) how exactly did these regulators co-evolve with
<figure><img src="image_138.png" /></figure>

each other and other transcriptional regulators to
become such important floral regulators, and (2) if
their ancestral function was also related to sexual
development. We use Yeast-Two Hybrid and Bifluo-
rescence Complementation assays to study protein
interactions and the CRISPR-Cas system for multiplex
Physcomitrium mutagenesis. We present our data on
(1) the protein interaction of the Physcomitrium and
other land plant LUG and SEU homologs and the pro-
tein domains important in the co-evolution between
LUG and SEU and their interactors, heterodimer for-
mation and for target protein interaction. Further, we
show that removing LUG and SEU function from the
Physcomitrium genomes results in growth retarda-
tion and present detailed phenotypic analysis of the
LUG and SEU mutants of Physcomitrium.

S.54.5 Because sex cells: patterning of gametangia in land plants and specification of gametes in the fern Ceratopteris richardii

Elissa S. Sorojsrisom¹,², Eva Uddin³, Tynisha Smalls², Barbara A. Ambrose²

1 Columbia University. New York, NY, USA. 2 New York Botanical Garden. Bronx, NY, USA. 3 The Bronx High School of Science. Bronx, NY, USA.

The fundamental sexual reproductive structures of
the gametophyte are the archegonium and anther-
idium (together called gametangia), which produce
egg and sperm respectively. The gametangia show
remarkable morphological conservation across
nonvascular and free-sporing vascular plants but
are structurally reduced in seed plants. Many stud-
ies have investigated the molecular genetics of ga-
metophyte development in angiosperms, as well as
in some Bryophytes, but broad comparative studies
are lacking. Furthermore, whether and how the gam-
etes produced by the gametangia are homologous
across green algae and land plants is not known. Al-
though analyses of patterning provide strong working
hypotheses, contributions from molecular genetics
and functional studies will be necessary to determine
the complete story of how these structures and the
gametes they produce have changed throughout
the evolution of land plants. We aim to fill this gap
with developmental genetic analyses in the mod-
el fern, *Ceratopteris richardii*, using a transcriptomic

and candidate gene approach. Using bulk RNA-seq
of six developmental stages, we developed a time
series transcriptome atlas for the gametophyte of
C. richardii. This dataset has allowed us to under-
stand broad patterns of gene expression changes
throughout gametophyte development, investigate
dynamics of shared vs. unique gene expression be-
tween life stages, and identify promising targets for
further functional analyses. Our candidate approach
focuses on TALE homeodomain (TALE-HD) proteins
that specify the identity of distinct gametes. Following
fertilization, proteins from distinct TALE-HD subclasses
form a heterodimer and translocate to the nucleus
to initiate the transition from gametophyte to sporo-
phyte in Chlorophyte algae and Bryophytes. Howev-
er, whether these genes retain this function in ferns is
currently unknown. We are combining our transcrip-
tome atlas with in situ hybridization and phylogenet-
ic analysis to understand the evolution of TALE-HD
proteins, and leveraging these new data in ferns to
create a comparative framework for understanding
gametangia evolution.
**S.55 PLANT RESPONSES TO STRESSES AND CLIMATE CHANGE. SESSION 2**

**S.55.1 The widespread Quercus ilex L. dieback in Mediterranean forests: investigation of the causes at plant and ecosystem level**

Cecilia Brunetti¹,²*, Francesca Alderotti¹,², Fabiano Sillo¹, Antonella Gori¹,², Mauro Centritto¹, Francesco Ferrini¹,²,³, Dalila Pasquini², Matthias Saurer⁴, Filippo Bussotti², Martina Pollastrini¹,², Raffaella M. Balestrini¹, Paolo Cherubini⁴

1 National Research Council of Italy (CNR), Institute for Sustainable Plant Protection, Sesto Fiorentino and Turin, Italy. 2 University of Florence, Department of Agriculture, Food, Environment and Forestry, Sesto Fiorentino, Italy. 3 National Biodiversity Future Center, Palermo Italy. 4 WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland. *cecilia.brunetti@ipsp.cnr.it

Over the past two decades, the occurrence of extreme climatic events in the Mediterranean region has increased, and this climatic pressure has contributed to the spread of vegetation dieback over several forest communities. Dieback has also affected Quercus ilex L., and since this decline has worsened over the last 15 years in many Mediterranean areas, it is crucial to develop effective tools for studying this phenomenon combining different scales of measurement. Our study was conducted over four years (2019-2023) in declining (D) and non-declining (ND) Q. ilex stands in southern Tuscany, assessing physiological and biochemical traits such as gas exchange, water relations, carbohydrate analysis in the wood, and xylem sap isotopic signal (δ¹⁸O). Dendrochronological and tree-ring δ¹³C analyses were combined to investigate the effects of previous droughts on tree growth and water-use efficiency. Lastly, changes in vegetation structure were assessed to monitor the impact of holm

oak mortality at the ecosystem level. The results of physiological analyses showed that seasonality had a strong effect on these traits, with the main stress occurring during the summer of 2020, as evidenced by the lowest gas exchange values. According to the results of δ¹⁸O analyses, holm oaks mainly took up water from deep soil sources (bottom soil or ground water) owing to their deep-root systems, resulting in only slightly different ring-width patterns and a low responsiveness to seasonal climatic variations in both stands. By contrast, the δ¹³C results combined with SSR genotyping revealed a more conservative water use of the population in the ND stand, underlying the potential of combining these powerful tools for the selection of seed-bearing genotypes putatively tolerant to water deficit. Furthermore, significant changes in the understory plant community highlight that Q. ilex dieback strongly affects the vegetation structure of Mediterranean forests.

**S.55.2 Tolerance to herbivory is maintained in insular herbivore-extinct ecosystems.**

Miquel Capó¹, Antoni J. Far², Pere M. Mir-Rosselló²,³, Carles Cardona³,⁴, Brígida Fernández de Simón⁵, Ramón Perea¹, Ismael Aranda⁵, Jaume Flexas², Marc Carriquí²,⁵

1 Plant and Animal Ecology Lab. Centro para la Conservación de la Biodiversidad y el Desarrollo Sostenible. Departamento de Sistemas y Recursos Naturales, Universidad Politécnica de Madrid, Madrid, Spain. 2 Grup de recerca en Biologia de les Plantes en Condicions Mediterrànies, Departament de Biologia, Universitat de les Illes Balears, Institut d'Investigacions Agroambientals i d'Economia de l'Aigua, Palma, Illes Balears, Spain. 3 Grup d'Ecologia Interdisciplinar, Departament de Ciències i Tecnologia, Universitat de Barcelona, Barcelona, Spain.
<figure><img src="image_139.png" /></figure>

tament de Biologia, Universitat de les Illes Balears, Palma, Spain. 4 Centre Forestal de les Illes Balears (CEFOR-Finca de Menut), Institut Balear de la Natura, Palma, Spain. 5 Instituto de Ciencias Forestales (INIA), CSIC, Madrid, Spain

Plant responses to herbivory play a crucial role in maintaining ecosystem functionality. While a trade-off between resistance and tolerance to herbivory has been theorized, recent studies challenged this dichotomy, as they showed that species might possess in-between behaviour. Additionally, the study of enemy release processes suggests that plant responses to herbivory ameliorate after herbivore disappearance. Based on these premises, we set an experiment with the non-palatable insular-endemic shrub *Hypericum balearicum* to assess its capacity to respond to herbivores. We conducted a comprehensive assessment of real herbivore interaction with *H. balearicum* in natural areas and examined plant responses following simulated herbivory. For this, we cultivated *H. balearicum* individuals at the Forestal Centre of the Balearic Islands. From all, we planted 90 in each of two natural areas in-habited by feral goats and sheep. To isolate the impact of herbivores, half of the plants at each site were excluded. Simultaneously, 90 individuals were maintained in a plant nursery for a simu-lated experiment involving two induced herbivory treatments: moderate and severe. After 45 days, we measured various physiological, biochemical and growth parameters associated with herbiv-ory response. Plants in natural areas showed no signs of herbivore predation, indicating an ab-sence of herbivory on this species. Nevertheless, the response capacity remained evident. Follow-ing induced herbivory, we observed maintained net photosynthesis but increased chlorophyll concentration, specific leaf area and Root:Shoot ratio in response to increasing treatment inten-sity. Severe herbivory simulation induced oxida-tive stress, and variations in the concentration of 47 leaf secondary compounds were reported across all treatments. Our findings challenge the conventional notion that resistant plants lack mechanisms to respond after herbivory when evolutionary pressures are absent. This study un-derscores the importance of considering histori-cal factors, such as the presence of extinct her-bivores or traits originated by exaptation, in the assessment of plant-herbivore interactions.

### S.55.3 Predicting drought tolerance-related biomarkers in maritime pine (Pinus pinaster Ait.) using machine learning

Irene Cobo-Simón¹, Nicolás Lobato², Julio Ramírez-Guerrero², Lorenzo F. Manjarrez¹, Nuria de María¹, Miriam López-Hinojosa¹, María Dolores Vélez¹, Paula Ramos¹, José Antonio Mancha¹, Alberto Pizarro³, José Antonio Cabezas¹, María Ángeles Guevara¹, Carmen Díaz-Sala³, María Teresa Cervera

1 Institute of Forest Science - National Institute for Agricultural and Food Research and Technology, Spanish National Research Council, Madrid, Spain.
2 University of Seville, Seville, Spain.
3 University of Alcalá, Alcalá de Henares, Spain.

Knowledge about the molecular and functional mechanisms that control the adaptation of trees to drought is key in the current context of climate change, since recurrent drought is one of the main climatic factors threatening forests, particularly in the Mediterranean region. However, this knowledge is scarce, especially in conifers, due to their huge and complex genomes. *Pinus pinaster* is one of the conifers with the greatest socioeconomic (for wood and resin production) and ecological importance in southwestern Europe, given its adaptive capacity. Recent advances in sequencing technologies enable the generation of large amounts of omics data, introducing a new era of "big data" in biology. Machine learning (ML), a branch of Artificial Intelligence (AI), offers promising approaches to recognize fine-grained patterns and relationships in these large and heterogeneous datasets, helping bridge the gap between our capability to produce and analyze plant molecular data. Here, we explore the potential of machine learning in predicting drought tolerance-related molecular biomarkers in maritime pine (*P. pinaster*). To this end, we used transcriptomic data from grafted rootstocks of genotypes with contrasting response to drought (tolerant and sensitive). Machine learning algorithms were used to analyze the expressed genes on these grafted rootstocks under controlled drought conditions to obtain accurate predictions of their tolerance/sensitiveness to drought. The methodology includes data selection and preprocessing, feature
<figure><img src="image_140.png" /></figure>

selection, model development, and evaluation. The obtained drought-tolerance molecular biomarkers can be used to guide the design of breeding and management programs, such as marker assisted selection and breeding, which will help improve the conservation, health, and productivity of this conifer in the long term. They can be also used in future drought-response research (e.g. comparative genomic studies, functional transfer across species) which will shed light on trees' molecular adaptive potential to current climate change.

## S.55.4 Novel approach to link the physiological response of maize (Zea mays L.) to drought and the occurrence of mycotoxins

Giacomo Boscarol¹, Elisa Petrussa¹, Giacomo Trotta¹,², Francesco Boscutti¹, Dora Scarpin¹, Enrico Braidot¹, Valentino Volpe³, Stefano Barbieri³, Michele Fabro³, Marco Vuerich¹

1 University of Udine, Udine, Italy. 2 University of Trieste, Trieste, Italy. 3 Servizio fitosanitario e chimico, ricerca, sperimentazione e assistenza tecnica, ERSA, Pozzuolo del Friuli, Italy

One of the effects of global change is the alteration of hydrological events, which affects many human activities, including agricultural ones. Understanding how maize (Zea mays L.), one of the most important staple crops worldwide, responds to these modifications is important to adapt to climate change. Drought stress during maize germination, flowering and pollination can lead to decreased plant growth, nutrient uptake, and grain yields. Prolonged periods of drought can also significantly increase the spread of diseases, which reduces yield quality. In this context we monitored 40 maize fields composed by both irrigated and non-irrigated areas, along a pedoclimatic gradient in NE Italy, throughout the 2022 and 2023 seasons, at four phenological stages (i.e., beginning of stem elongation, flowering, milk maturation, dent maturation). In particular, we considered the plant individual functional response (i.e., plant height, SLA, leaf DMC, leaf chlorophyll, carotenoid and flavonoid content, kernel DW, kernel C:N, kernel δ¹³C), and the kernel mycotoxins content (aflatoxins and fumonisins), in relation to irrigation conditions and climate data (i.e.,

total precipitation, mean temperature). We found that the soil structure effect was overruled by the effect of climate and/or irrigation. As we expected, the absence of irrigation and low total precipitation led to a reduction of plant biomass and kernel production, whereas interaction between irrigation and phenological stage had significant effects on leaf pigments (i.e., chlorophyll) and secondary metabolites (i.e., flavonoid). Moreover, irrigation enhanced the kernel C:N ratio and δ¹³C, whereas reduced the amount of aflatoxins. Our further investigations aim at evaluating the interplay between the climatic variables, the soil structure, and the individual traits on the ultimate content of mycotoxins in the kernel, with two distinct irrigation regimes and at the given different phenological stages, adopting a structural equation modelling approach.

## S.55.5 Observing Shifts In Global Tropical Flowering Phenology

Skylar Graves¹, Gladiana Spitz¹, Brett Melbourne¹, Nancy Emory¹, Patrick Sweeny¹, Julian Resasco¹, Erin Manzitto-Tripp¹

1 Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, Colorado, USA. COLO Herbarium, University of Colorado Boulder, Boulder, Colorado, USA

Shifts in flowering phenology can have cascade effects across entire ecosystems and can be indicators of more severe climate change effects. Large scale, multi-taxon studies investigating flowering phenology have been limited to non-tropical latitudes. This study analyzes changes in flowering times at 20 localities across the global tropics. I have found that from 1850 to 2021, flowering times have shifted significantly at all locations, on average 97.6 days across all sites. This ranged from 55.5 days shifted at Las Cruces Research Station in Costa Rica to 109.9 days shifted at Korup National Park, Cameroon. The Neotropics have undergone an average of 80.9 days shifted, the Afrotropics an average of 91.9 days shifted, and Southeast Asia an average of 102.6 days shifted. These shifts could be indicative of greater ecosystem-wide changes. A changing of flowering time can be an indicator for larger impacts of climate change, however it is important to take duration of flowering period into account when analyzing the impact the shift in flowering may cause.
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## S.55.6 Overexpression of *BvNHX1* from sugar beet (*Beta vulgaris*) confers enhanced salt tolerance in transgenic tobacco

Guo-Qiang Wu¹, Xin-Miao Zhang¹, Ming Wei¹, Hong-Xia Kang¹

1 School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, China

Salinity is one of the major environmental factors that limit the plant growth and crop productivity worldwide. Tonoplast Na⁺/H⁺ transporters (NHXs) play crucial roles in regulating the intracellular Na⁺/K⁺ and pH homoeostasis, which is essential for salt tolerance and development of plants. In the present study, a novel gene *BvNHX1* encoding tonoplast Na⁺/H⁺ antiporter was isolated in natrophilic crop sugar beet (*Beta vulgaris*) and functionally characterized in tobacco (*Nicotiana tabacum*) plants to

assess the behavior of the transgenic organisms in the response to salt stress. The results showed that overexpression of *BvNHX1* significantly enhanced salt tolerance in transgenic tobacco plants compared with wild-type (WT) plants. The seed germination, root length, plant height, and fresh and dry weights in transgenic plants were significantly higher than those in WT plants under salt stresses. The contents of leaf relative water, chlorophyll, proline, soluble sugars, and soluble proteins were significantly higher as compared with WT plants, while malondialdehyde (MDA) contents were significantly lower than those of WT plants under salt stresses. Na⁺ and K⁺ contents both in shoots and roots of transgenic plants were significantly higher than those of WT plants, and transgenic plants maintained a balanced K⁺/Na⁺ ratio under saline conditions. Taken together, these results suggested that overexpression of *BvNHX1* reduced damage to cell membrane by reducing osmotic potential of cells, and maintaining relative water and chlorophyll contents of leaves, and finally improved salt tolerance in transgenic tobacco plants.

## S.56 PLANT CONSERVATION GENETICS: FROM IN-SITU AND EX-SITU CONSERVATION TO REINTRODUCTIONS AND RESTORATIONS. SESSION 2

### S.56.1 Using gene rescue theory to improve the success of conservation translocations

Aline Finger¹, Mike Smedley², Duncan Halley³, Martine Borge¹, Antje Ahrends¹

1 Royal Botanic Garden Edinburgh, Genetics & Conservation, Edinburgh, UK. 2 NatureScot, Inverd ee House, Torry, Aberdeen, UK. 3 Norsk institutt for naturforskning, Sluppen, Trondheim, Norway

We present a study that uses genetic rescue (an improved fitness due to the introduction of new genes) theory to help maximise the success of conservation translocations, the deliberate movement of plants for conservation purposes. Species in need of translocations often remain as small, scattered and isolated

populations. This makes them vulnerable to genetic problems, such as genetic erosion, inbreeding depression and a lowered evolutionary potential. These genetic problems can decrease plant fitness and consequently make recovery work more difficult. Genetic rescue can help to overcome fitness declines in small populations and mixing genes can be a strong tool for creating more suitable plant material for translocations. Here, we put genetic rescue theory to practice, including all associated steps, such as gathering genetic background information on the study species, cross-pollinations in a nursery, and translocations. We're using the alpine blue-sowthistle (*Cicerbita alpina*) as an example, which is only left in four very small populations in Scotland, UK, where it fails to reproduce. Like so many other species, *C. alpina* is unlikely to recover naturally and could be lost without human interventions. We demonstrate that cross-pollinations improve plant fitness (plant size, survival, flowering) at
<figure><img src="image_142.png" /></figure>

translocation sites. Mixing genes prior to planting species out can help increase the success of conservation translocations but requires time, space and expertise.

## S.56.2 Population genetics for the conservation of three endangered Magnolia species from Chiapas and Guatemala

José Antonio Vazquez-García¹, Emily Coffey², Lauren Eserman², Amanda Carmichael², Jean Linsky², Maria Voguel², Erick Tribouillier Navas³, Fredy Archila⁴, Francisco Hernández Najarro⁵, Sangtae Kim⁶, Suhyeon Park⁶, Alma Rosa Villalobos Arámbula¹, Viacheslav Shalisko¹

1 University of Guadalajara, Jalisco, Mexico. 2 Conservation & Research Department, Atlanta Botanical Garden, GA, USA. 3 Estación Experimental de Orquídeas de la Familia Archila, Cobán, Guatemala. 4 Universidad de San Carlos de Guatemala, Guatemala City, Guatemala. 5 Universidad de Ciencias y Artes de Chiapas, Tuxtlá Gutiérrez, Mexico. 6 Sungshin Women's University, Seoul, Republic of Korea

Understanding the genetic structure of populations is crucial for conservation purposes of endemic or geographically restricted species, to ensure that ex-situ propagation and conservation efforts include a representative sample of the species' genetic diversity existing in nature. In the case of *Magnolia*, the complex physiographic environment and climatic diversity in southern Mexico and Guatemala results in the existence of species restricted in their distribution to certain mountain ranges, representing examples of either paleo- or neoendemisms. The reduction of habitats due to land use change, deforestation, and climate change consequently places some species in a particularly vulnerable state, requiring urgent implementation of conservation measures to prevent extinction. The species *Magnolia faustinomirandae*, *M. montebelloensis*, *M. quetzal*, are characterized by having highly restricted populations of only a few dozen individuals known in the wild, in addition to those included in propagation programs. Data obtained from the analysis of known wild populations of three species using targeted genomic sequencing revealed rather limited genetic diversity in *M. quetzal*. In the case of morphologically similar species *M. montebelloensis*

and *M. faustinomirandae*, the population of the latter from Chiapas highlands demonstrated a genetic identity distinctively separated from the rest of the samples. It was revealed that some individuals morphologically similar to *M. faustinomirandae* in Guatemala are indeed part of *M. montebelloensis* diversity, which has been confirmed by more exhaustive morphological analysis. Therefore, authentic *M. faustinomirandae* is restricted to Chiapas highlands. Regarding *M. montebelloensis*, its populations in Las Vegas de Montebello showed genetic similarity with those in Quiché, Guatemala, being the most diverse species in the analysis. The analysis suggested the possibility of a cryptic *Magnolia* species in Guatemala, distinct in its genetic composition, known from a cultivated population in the Monastery site, that is currently under morphological revision.

## S.56.3 Genomic signatures of inbreeding depression and mutation load in a threatened African timber tree, *Pericopsis elata* (*Fabaceae*)

Surabhi Ranavat¹, Dieu-Merci Assumani¹,², Crispin Ilunga-Mulala³,⁴, Jean Pierre Ngongo¹,⁵, Bonaventure Sonké⁶, Nils Bourland⁷, Jean-François Flot¹, Olivier Hardy¹

1 Ecology and Evolutionary Biology, Université Libre de Bruxelles, Brussels, Belgium. 2 Faculty of Renewable Natural Resources Management, University of Kisangani, Kisangani, Democratic Republic of Congo. 3 Gembloux Agro-Bio Tech, Forest Is Life, TERRA Teaching and Research Centre, University of Liège, Gembloux, Belgium. 4 Department of Environment, Faculty of Sciences, Université du Cinquantenaire de Lwiro, Lwiro, Democratic Republic of Congo. 5 Faculty of Sciences, University of Kisangani, Kisangani, Democratic Republic of Congo. 6 Plant Systematic and Ecology Laboratory, University of Yaoundé I, Yaoundé, Cameroon. 7 Service of Wood Biology, Royal Museum for Central Africa, Tervuren, Belgium

*Pericopsis elata* is a large, gregarious, and light demanding tree distributed in the Western and Central African tropics. Highly exploited for its excellent quality timber, it is listed as endangered on the IUCN Red List and included in the CITES Appendix II. It is a peculiar tropical tree as it has a mixed-mating system, with a high selfing rate, and a lack of regeneration throughout its natural distribution
<figure><img src="image_143.png" /></figure>

range. Previous results from Democratic Republic of Congo (DRC) showed a high proportion of inbred individuals, with 54% inbreeding in seeds and seedlings, and 20% in adults, indicating inbreeding depression. Recently, two highly differentiated gene pools ($F_{ST}=0.53$) were identified in DRC (Eastern gene pool), and Republic of Congo and Cameroon (Western gene pool). Along the Western gene pool, we observe a steep westward decay of heterozygosity, and we hypothesize that this is a recent range expansion into Cameroon with founder effects, possibly facilitated by selfing. Our aim is to assess inbreeding depression and mutation load along this westward expansion. Whole genome resequencing data of individuals along this gradient will be used to detect the runs of homozygosity (ROH), which will aid in inferring the demographic history and finding deleterious variants. To detect the mutation load, we test if there is a westward decay of the ratio of synonymous to non-synonymous mutations, and the predicted effect of amino acid substitution on protein function based on sequence homology across closely related species. On the range expansion front, we expect longer ROHs, and an increase in inbreeding coefficient and mutation load towards the west. These analyses, combined with phenotypic data, will help in identifying the effects of inbreeding and informing sustainable management strategies for this threatened timber tree.

capture approach Angiosperms353 to capture the genetic structure and diversity of small regionally endangered populations within three distinct species for which conservation action plans are developed in Switzerland (*Blackstonia acuminata*, *Eryngium campestre*, and *Lythrum hyssopifolia*). For each of the three species, we could successfully identify a minimum of 900 non-linked Single Nucleotide Polymorphisms (SNPs) in exonic and flanking intronic regions. The analysis of these SNPs revealed contrasting patterns of population structure, genetic diversity, and hybridization levels, even at a very local scale. In *Blackstonia*, our results show the clear differentiation of morphologically similar species (*B. acuminata* and *B. perfoliata*) and reveal in *B. acuminata* a hybridization level indicative of a hybrid taxon likely reproducing through apomixis. *Eryngium campestre* exhibited distinct population lineages associated with the drainage systems in which they were situated. *Lythrum hyssopifolia* revealed both its polyploid nature and significant population differentiation. Although Angiosperms353 was developed to study species relationships due to the high conservation level of the targeted genes, we demonstrate the efficacy of this kit at the population level. Its many advantages such as direct applicability, cost-effectiveness, compatibility with herbarium samples and a better data interoperability could facilitate the use of genetics for rapidly assessing genetic diversity and structure with the aim of informing conservation actions.

## S.56.4 Angiosperms353 for population genetics of regionally threatened plant species

Camille Christe¹, Nathan Cornide¹², Andreas Ensslin¹, Yamama Naciri¹², Mathieu Perret¹²

1 Conservatoire et Jardin botaniques de Genève, Pregny-Chambésy, Switzerland. 2 Department of Plant Sciences, University of Geneva, Genève, Switzerland

Intra specific genetic diversity is a key component of biodiversity, but it has frequently been overlooked in conservation studies due to the difficulties to study it. Conservation programs often need a genetics assessment of the target populations to guide specific actions, such as source population to use in reinforcement or reintroduction. Here we test the effectiveness of the universal targeted sequence

## S.56.5 Genomics for conservation of Mexican agaves and cactus

Diana Itzel Martínez-Lona¹, Michelle Cabrera-Guerra², Eddy Mendoza-Galindo³, Tania Hernández-Hernández⁴

1 Ciencias Agrogenómicas, Escuela Nacional de Estudios Superiores, Universidad Nacional Autónoma de México, León, Mexico. 2 Department of Genetics, Faculty of Biology, Ludwig Maximilians Universität, Munich, Germany. 3 Centro de Investigación y de Estudios Avanzados del IPN (Cinvestav), Irapuato, Guanajuato, Mexico. 4 Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ, USA

Mexico is one of the few biodiversity hotspots for both wild and domesticated plants in the world. Many species, varieties and landraces can only be found in the region; due to geographical, biological and cultural reasons. Approximately 75%
<figure><img src="image_144.png" /></figure>

of species of Agave are endemic and 84% of the cactus found in Mexico are found only here. The most recent assessments from conservationist groups reveal that both Agave and cactus species are the most endangered, threatened of extinction mostly from illegal poaching, change in land use and global warming. Unfortunately, there are still few genomic resources available for both taxonomic groups, and the research community is in high need of tools such as reference genomes, SNP panels and methodological approaches to better understand the biology to these long-lived wild species and inform conservation strategies. During this talk, we explain some of the research initiatives of Desert Botanical Garden in collaboration with several institutions in Mexico and the community to study and preserve both cactus and Agave biodiversity using genomic tools. We

leverage on the popularity and economic relevance of two flagship species: *Carnegiea gigantea* (saguaro cactus) and *Agave tequilanavar*. Azul ('blue' tequila agave). Although these species are not endangered, through their study we develop tools and raise awareness towards conservation, not only of species but also varieties and landraces. We explain our study of the columnar saguaro cactus and the efforts we are making to involve and actively engage the community to set awareness of climate change and their effects in cactus biodiversity. We also talk about our efforts to document and preserve the almost lost mezcal and tequila traditional Agave landraces, threatened by the enormous demand for only two cultivars that produce the spirits that are highly sought-after in the USA and Europe.

**S.57 GENOMIC APPROACHES TO**
**UNDERSTANDING THE ECOLOGY AND**
**EVOLUTION OF SYMBIOTIC AND NON-**
**SYMBIOTIC MICROALGAE. SESSION 1**

**S.57.1 Genome of the glacier alga Ancylonema and its insights into the evolution of streptophyte life on ice and land**

Alexander M. C. Bowles¹,²,³, Tom A. Williams², Philip C. J. Donoghue², Douglas A. Campbell⁴, Christopher J. Williamson¹

1 School of Geographical Sciences, University of Bristol, University Road, Bristol, UK. 2 Bristol Palaeobiology Group, School of Biological Sciences and School of Earth Sciences, Life Sciences Building, University of Bristol, Bristol, UK. 3 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, UK 4 Department of Biology, Mount Allison University, Sackville, NB, Canada

Contemporary glaciers and ice sheets are home to communities of streptophyte glacier algae that must balance their requirements for photosynthesis and growth with tolerance of extremes in temperature, desiccation and UV radiation. These same

environmental challenges have been hypothesized as the driving force behind the evolution of land plants from streptophyte algal ancestors in the Cryogenian (720-635 Mya ). Here, we sequence, assemble and analyze the metagenome-assembled genome (MAG) of the glacier alga *Ancyloneema nordenskiöldii* to investigate its adaptations to life in ice, and whether this represents a vestige of Cryogenian anydrophyte exaptations. Phylogenetic analysis confirms the placement of glacier algae within the sister lineage to land plants, Zygnematophyceae. The MAG is characterized by an expansion of genes involved in high irradiance and UV light tolerance, whilst lineage-specific diversification led to the novel screening pigmentation of glacier algae. We found no support for the hypothesis of a common genomic basis for adaptations to ice and to land in streptophytes. Comparative genomic analysis revealed that reductive genome evolution in the ancestor of Zygnematophyceae correlates with their reductive morphological evolution. This first genome-scale data for glacier algae supports an Ancylonema-specific adaptation to the cryosphere, as well as shedding light on the genome evolution of land plants and Zygnematophyceae.
<figure><img src="image_145.png" /></figure>

### S.57.2 From thalli to holobiome genomes: reappraisal of lichens as biomonitors for forest health

Patricia Moya¹, Tamara Pazos¹, Salvador Chiva¹,², Isaac Garrido-Benavent³, Pavel Skaloud⁴ and Eva Barreno¹.

1 Institut Cavanilles de Biodiversitat i Biologia Evolutiva-Departament de Botànica, Universitat de València, Burjassot, València, Spain. 2 University of Trieste, Trieste, Italy. 3 Universitat de València, Burjassot, València, Spain. 4 Faculty of Science, Czech Republic

Lichens are one of the most emblematic examples of the mutualistic associations between one fungi and populations of photosynthetic green microalgae and/ or cyanobacteria. Aside from these major lichen symbionts, an indeterminate number of other microorganisms, co-occur, intermingled in these associations. Given all of these new "players", the traditional lichen paradigm is evolving into a broader concept of lichen holobiomes. Advances in genomics and bioinformatics have provided a deeper understanding of this diversity. Therefore, lichen thalli are considered microecosystems in which numerous different symbiotic partners can interact. The fine functioning balance established in the thalli is one of the reasons for their recognition as bioindicators. Lichens are sensitive to a variety of anthropogenic disturbances, and are widely used as rapid bioindicators of both small-scale and global change. In the 1990s, a sampling network for the biomonitoring of forests using epiphytic lichen diversity was established in eastern Spain. In 1997, an assessment of the state of lichen communities was carried out and the results were published. In 2022, this previously established biomonitoring network was reevaluated. To compare the results obtained in 1997 and 2022, the same methodology was used, and data from air quality stations were included. The results displayed a significant general decrease in the diversity and a generalised increase in damage symptoms in target lichen species, which seem to be the consequence of a multifactorial response (climatic and pollution). Taking advantage of this new sampling, genomic data were obtained from 188 thalli to explore lichen community structure. Our results showed differences in photobiont choice between sexually and asexually reproducing lichens in the epiphytic community. Using metagenomic approaches we explored the differences between the composition of microorganisms amongst healthy and damaged

thalli. Our results provide a renewed perspective for biomonitoring.

Acknowledgments: PROMETEO/2021/005 (GVA to EB), EU-MS21-058 (to SC), PID2021-127087NB-100 (MICIN to IGB)

### S.57.3 Comparative genomics in Chlorophyceae: an exploration to the green OCC clade

Yanä C. Rizzieri¹,², Fay-Wei Li¹,²

1 Boyce Thompson Institute, Ithaca, USA. 2 Plant Biology Section, Cornell University, Ithaca, USA.

In Chlorophyceae, the OCC clade (Oedegoniales, Chaetopeltidales and Chaetophorales) corresponds to more than a thousand of understudied algae species. They present a variety of interesting features such as the diversity of cellular organization complexity, presence/absence of plasmodesmata, and CO2 concentration mechanisms. However, the lack of genomic resources from the OCC clade limits further investigation into their unique biology. To address this genomic gap, we are currently sequencing four genomes that cover all the three orders in the OCC clade, using a combination of short and long read sequencing, as well as Hi-C scaffolding approach. We expect the resulting chromosome level genome assemblies will not only shed light into the genomic landscape in the OCC clade, but also form the basis for broader comparative analyses across chlorophyte algae.

### S.57.4 Comparative genomics sheds light on the ecology and evolution of dryland green microalgae

Veronica Malavasi¹,², Núria Beltran-Sanz¹, Sofia Stocco¹, Fernando T. Maestre³, Francesco Dal Grande¹

1 University Centre Botanical Garden, University of Padua, Italy. 2 Department of Botany, Charles University, Prague, Czech Republic. 3 Department of Ecology, University of Alicante, Spain

In dryland ecosystems, soil microbial communities are intricately linked to ecosystem functioning because they play an important role in carbon and nitrogen
cycling, soil fertility and climate regulation. Unicellular green algae are crucial components of these communities with key roles in primary production, food webs, nutrient cycling, soil formation, and modulation of soil texture and structure. Despite its importance and interest in biotechnological exploitation, the phototrophic micro-algal flora represents a vastly understudied component of soil microbial communities. Limited knowledge of the diversity and the adaptive traits important for survival in extreme environments translates into a limited ability to monitor and eventually prevent biodiversity losses. This study aimed to create a genomic library of representative strains of green algae isolated from desert soils worldwide. A collection of 23 soil samples from 14 countries, collected within the framework of the BIODESERT project, was used for this purpose. The newly generated genomes and transcriptomes from several strains representing over 15 genera of the Chlorophyta and Charophyta divisions allow testing the hypothesis of genomic convergence in the adaptation to desert environments in green algae. Our newly genomic library constitutes a novel resource for metagenomics-based monitoring of functional biodiversity in desert soil microbial communities and a better-informed prediction of the ecological implications of climate change on soil biodiversity. Additionally, the results of this initial screening pave the way for the biotechnological exploitation of this vital yet understudied component of desert ecosystems.

## S.57.5 How to find the right partner? Omics approaches unveil the mysteries behind the formation of lichen symbiosis

Pavel Skaloud¹, Lucie Vancurova¹, Veronika Vesela¹, Zuzana Skvorova¹, Jana Steinova¹, Ivana Cernajova¹, Patricia Moya², Ondrej Peksa³

1 Department of Botany, Charles University, Prague, Czechia. 2 Botánica, ICBIBE, Universitat de València, Valencia, Spain. 3 Museum of West Bohemia in Pilsen, Pilsen, Czechia

Symbiotic organisms play a key role in natural communities. However, the mechanisms underlying the selection of symbiotic partners remain largely unknown. Over the past few years, we have aimed to understand the formation of lichen symbiotic associations by examining and comparing the diversity of endosymbiotic

and free-living algae in the environment using a combination of eDNA metabarcoding and Sanger sequencing. In many cases, we revealed highly contrasting patterns of diversity, suggesting that the symbiotic inventory of lichen communities does not reflect the diversity of free-living algae. In particular, many symbionts that associate only with asexual lichen species have never been found at a site outside of lichen thalli, although various substrates, including aeroplankton, have been examined for the presence of free-living algae. Such findings strongly violate the paradigm of habitat-adapted symbiosis, as fungal hosts obviously do not select their algal partners from a regional pool of adapted species. Moreover, we hypothesize that some of the symbionts absent from the environment may exhibit a high degree of dependence on the presence of symbiotic fungi or may even represent obligate symbionts that never occur in the free-living state.

## S.57.6 The photobiont cookbook: phylogenomics-informed recipes to make lichen-palatable algae

Francesco Dal Grande¹,²,³, Camille Puginier⁴, Cyril Libourel⁴, Juergen Otte¹, Pavel Škaloud⁵, Mireille Haon⁴,⁶, Sacha Grisel⁴,⁶, Malte Petersen⁷, Jean-Guy Berrin⁴,⁶, Pierre-Marc Delaux⁴, Jean Keller⁴

1 Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt am Main, Germany. 2 LOEWE Centre for Translational Biodiversity Economics (TBG), Frankfurt am Main, Germany. 3 University of Padova, Padua, Italy. 4 Université de Toulouse, Toulouse, France 5 Charles University, Praha, Czech Republic. 6 Aix Marseille Université, Marseille, France. 7 University of Bonn, Bonn, Germany

Lichens are textbook examples of ecologically successful symbioses formed between thousands of fungal species and a handful of green algae. Their biology, ecology and physiology have been studied for centuries, with disproportionate focus on the fungal side of the symbiosis. By contrast, the evolutionary origins and molecular mechanisms of the symbiosis on the side of the green algal partner remain elusive. In this study we explored the evolutionary history and the molecular innovations in green algae at the origin of the ability to establish symbiotic association with fungi to form lichens. For this, we de novo sequenced the genomes or transcriptomes of 12 lichen-forming and closely related non-lichen-forming algae, filling key sampling gaps in
<figure><img src="image_146.png" /></figure>

the algal tree of life. We then combined this dataset with 129 previously sequenced green algae and performed comparative phylogenomic analyses to find genes discriminating lichen-forming and non-lichen-forming algae. In addition to gene-family expansions, we show that one carbohydrate-active enzyme, the glycosyl hydrolase 8 (GH8), was acquired in lichenizing Trebouxiophyceae by horizontal gene transfer from bacteria. Our

results suggest that the ability to degrade the partner's cell wall is a key acquisition for the evolution of symbiotic lifestyle in these algae. Our study unravels an important evolutionary event fundamental to the establishment of symbiotic lifestyle in lichenized algae and paves the way for future functional studies in this understudied yet ecologically important group of organisms.

# S.58 STILL STANDING: RIBOSOMAL DNA SIGNIFICANCE IN CURRENT PLANT RESEARCH

## S.58.1 Molecular architecture of rDNA loci and evolutionary dynamics of 5S and 35S rDNA repeats in duckweeds (Lemnaceae)

Anton Stepanenko¹,²,³, Guimin Chen¹, Phuong T.N. Hoang²,⁴, Todd Michael⁵, Eric Lam⁶, Ingo Schubert², Nikolai Borisjuk¹*

1 School of Life Sciences, Huaiyin Normal University, Huai'an, China. 2 Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany. 3 Institute of Cell Biology and Genetic Engineering, Kyiv, Ukraine. 4 Faculty of Biology, Dalat University, Đà Lat, Vietnam. 5 Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, USA. 6 Department of Plant Biology and Pathology, Rutgers the State University of New Jersey, New Brunswick, USA

Duckweeds, represented by 36 species in Lemnaceae family, are small, mostly vegetatively propagated aquatic plants with worldwide distribution and fast growth rate. Sequencing of 35S rDNA repeats in representative species of genus Spirodela, Landoltia, Wolffia and Lemna showed positive correlation of the repeats length with genome size, and significant sequence variability of the intergenic spacers. Our genome surveys of two most ancient duckweed species, S. polyrhiza (Michael et al., 2017) and S. intermedia (Hoang et al. 2020), revealed a very low representation of 35S and 5S rRNA genes, at around 100 copies per genome, and an unorthodox molecular structure of the usually conserved 35S rRNA transcription initiation site (TIS). The low rDNA copy number in Spirodela made possible to reveal detailed molecular organization of the species' rDNA loci through a combination of molecular cytolo-

gy, conventional sequencing and long DNA reads. The relatively GC-rich 35S rDNA and 5S rDNA arrays are imbedded in highly AT-enriched chromosome regions. Further sequence analysis demonstrated that the 5S rDNA repeat clusters, localized on two different chromosomal loci, and composed correspondingly of 40 and 60 repeat units have the non-transcribed spacers (NTS) of different size and different rates of sequence variability, suggesting contrasting evolutionary dynamics of the two types of 5S rDNA units. In summary, our findings put duckweeds in the spotlight of rDNA research, promising new insights into basic principles of organization and regulation of rRNA genes.

References: Michael et al. (2017) Plant Journal, 89(3):617-635. Hoang et al. (2020) Scientific Reports, 10(1):19230.

## S.58.2 Deconstructing ribosomal DNAs: an overview of ribosomal DNAs evolution and genomic arrangements in the sunflower family

Daniel Vitales¹, Joan Pere Pascual-Díaz¹, Teresa Garnatje¹, Andrew Leitch², Ales Kovarik³, Sònia Garcia¹

1 Institut Botànic de Barcelona (CSIC-CMCNB), Barcelona, Spain. 2 School of Biological and Chemical Sciences, Queen Mary University of London, London, UK. 3 Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic

Here we explore the evolutionary dynamism of ribosomal RNA genes (rDNA), a dynamism that
<figure><img src="image_147.png" /></figure>

is surprisingly high given their crucial role in the synthesis of ribosomes and thus for life-on-Earth. rDNA units are present in high numbers, from 50 to 13,000 copies per cell that are typically tandemly arranged at one or a few loci. However, despite their importance and abundance, several aspects of the biology remain enigmatic, particularly their mode of molecular evolution and genomic arrangements. We aim to deconstruct ribosomal DNA structure to define the model of evolution that best explains its high evolutionary dynamism and the differences in behaviour of 35S and 5S rRNA genes. We have used 74 species in the sunflower family (Asteraceae) as models for this analysis, which together represent a diversity of rDNA arrangements, genome sizes, ploidy levels, and rDNA copy numbers. Indeed, family Asteraceae shows a particularly large diversity of rDNA arrangements amongst its 24,000 species, including in subfamily Asteroideae (tribe Anthemideae and some tribes of the Heliantheae alliance), where there is an exceptional arrangement of 35S and 5S rRNA genes being linked together. Using next-generation sequencing (NGS) and analytical approaches we address central questions allowing us novel, fundamental insights into genomic mechanisms related to concerted evolution, pseudogenisation, the relationship with genome size and rDNAs or their interplay with transposable elements. Our results impact our global understanding of molecular evolution and repetitive DNA organisation in plant genomes.

### S.58.3 The plant nucleolus across the seed plants – ubiquitous but mysterious

Natalia Borowska-Zuchowska¹*, Ewa Robaszkiewicz¹, Artur Pinski¹, Bozena Kolano¹, Serhii Mykhailyk¹, Natalia Matysiak², Lukasz Mielanczyk²,³, Maria Drapikowska⁴, Ewa Kazimierczak-Grygiel⁵, Justyna Wiland-Szymanska⁵,⁶, Romuald Wojnicz²,³, Robert Hasterok¹

¹ Plant Cytogenetics and Molecular Biology Group, Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Poland. ² Department of Histology and Cell Pathology, Faculty of Medical Sciences in Zabrze, The Medical University of Silesia in Katowice, Poland. ³ Silesian Nanomicroscopy

Centre in Zabrze, Silesia LabMed – Research and Implementation Centre, Medical University of Silesia in Katowice, Poland. ⁴ Department of Ecology and Environmental Protection, Faculty of Environmental and Mechanical Engineering, Poznań University of Life Sciences, Poland. ⁵ Botanical Garden, Adam Mickiewicz University in Poznań, Poland. ⁶ Department of Systematic and Environmental Botany, Faculty of Biology, Adam Mickiewicz University in Poznań, Poland

The nucleolus is one of the most prominent structures in the eukaryotic cell due to its indispensable role in 35-45S rRNA gene transcription and subsequent ribosomal subunit assembly. In addition to proteins and rRNA, the nucleolus also contains the 35S/45S ribosomal DNA (35S/45S rDNA). These tandemly repeated genes encoding for 18S, 5.8S and 25/28S rRNA are transcribed as a single 45/35S pre-rRNA by DNA-dependent RNA polymerase I (Poll). Despite the presence of nucleolus in almost every eucaryotic cell, many questions about its structure and function remain unanswered. Also, the question of how diverse the nucleoli are among the different seed plant representatives is still pending attention. Hence, in this study, we aimed to shed new light on the seed plant nucleolus structure by integrating insights from the ultrastructure of nucleoli components and through the lens of modern superresolution microscopy. Both the model (such as *Brachypodium distachyon* and *Arabidopsis thaliana*, monocot and eudicot, respectively) and non-model species were analysed. The localisation of the selected nucleolar proteins, i.e., fibrillarin, nucleolin, and subunits of RNA Pol I, were visualized *in vivo* using the GreenGate cloning system. The patterns of selected nucleolar proteins were then compared with the 3-dimensional localisation of the decondensed fraction of 35S rDNA by fluorescent *in situ* hybridisation (FISH). As a result of our study, the functional characterisation of particular nucleolar components has been proposed, shedding new light on the role of the specific nucleolar subcompartments, e.g., the nucleolar vacuoles.

**Acknowledgments:** The gratefully acknowledge financial support from the National Science Centre, Poland (grant no. 2018/31/B/NZ3/01761 and 2018/02/X/NZ3/03197).
## S.58.4 Conserved sequence elements present in the 5S rDNA intergenic spacer occur in the genomes of distantly related angiosperms

Yurij O. Tynkevich¹, Irina I. Panchuk¹, Roman A. Volkov¹

1Yuriy Fedkovych Chernivtsi National University, Chernivtsi, Ukraine

Tandemly arranged repetitive regions (repeats) that encode 5S rRNA (5S rDNA) are an obligatory component of eukaryotic genomes. Typically, the 5S rDNA repeats within a genome are very similar due to the concerted nature of their evolution. Each 5S rDNA repeat consists of a conserved coding sequence (CDS) and a rapidly evolving intergenic spacer (IGS). The high evolutionary stability of the CDS is the result of purifying selection to maintain the function of the 5S rRNA as a component of the ribosome. In contrast, it is believed that the main part of the IGS probably has no function and therefore evolves at a high rate. To uncover the patterns of IGS evolution in a broad taxonomic context, we applied cloning, sequencing, and bioinformatic analysis to describe the molecular organization of 5S rDNA in 31 genera representing 15 families and 12 orders of angiosperms. It was found that the short-sequence motifs at the 3' and 5' ends of the IGS, which are involved in the initiation and termination of 5S rDNA transcription, evolve at a relatively low rate and demonstrate apparent conservation within a genus/family. Surprisingly, our analysis also revealed that in eight genera studied the middle part of IGS harbors conserved sequence elements (CSE), 50 to 200 bp in length, which show clear similarity (70 to 91%) to the genomic sequences of taxonomically distant families. This may be due to presumptive horizontal gene transfer. Alternatively, the CSE may represent ancient sequences that were conserved in some phylogenetic lineages. The function of CSE and the mechanism of its maintenance during long-term evolution remain enigmatic and require further research.

## S.262.5 Uniparental silencing of 5S rRNA genes in plant allopolyploids - first evidence from Cardamine (Brassicaceae)

Aleš Kovařík¹, Terezie Mandáková², Alice Krumpolcová¹,³, Roman Matyášek¹, Roman Volkov⁴, Martin Lysák²

1 Department of Molecular Epigenetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic. 2 Central European Institute of Technology, Masaryk University, Brno, Czech Republic. 3 Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic. 4- Yuriy Fedkovych Chernivtsi National University, Chernivtsi, Ukraine.

**Introduction:** While uniparental silencing of 35S rDNA in interspecific hybrids and allopolyploids is a well-known phenomenon there is no information on whether silencing also affects the 5S RNA component of ribosomes. To address this question, we analyzed the expression of 5S rDNA and 26S rDNA in Cardamine (Brassicaceae) allopolyploids including *C. × insueta* (genome composition ARR, 2n=3x=24), *C. flexuosa* (AAHH) and *C. scutata* (AAPP) (both 2n=4x=32). These combine diploid genomes derived from *C. amara* (A-genome) shared by all three allopolyploids and divergent genomes derived from *C. rivularis* (R-genome), *C. hirsuta* (H-genome) and *C. parviflora* (P-genome) (all 2n=2x=16). Bioinformatic pipelines included high-throughput sequencing of transcriptomes and genomes followed by variant calls and phylogenetic analyses of ribotypes. Genomic organization of rDNA was analyzed by SNPs, clustering and rDNA FISH. **Results:** In *C. × insueta* allotriploid hybrid we observed uniparental dominant expression of 35S and 5S rDNA loci from the *C. rivularis* genome. In *C. flexuosa* and *C. scutata* allotetraploids 35S rDNA was expressed from the A-genome while 5S rDNA was expressed from the partner H- and P- genomes, respectively. FISH showed relatively intact 5S and 35S loci in *C. × insueta* (twenty populations) while both *C. flexuosa* and *C. scutata* allotetraploids showed copy and locus number changes. Intergenomic translocation of the H-genome 5S rDNA was identified in all populations of *C. flexuosa* which however did not influence its dominant expression. **Conclusion:** Both 5S and 35S rDNA loci undergo uniparental silencing in Cardamine allopolyploids. In stabilized allopolyploids both rDNA loci are transcribed from different
<figure><img src="image_148.png" /></figure>

subgenomes. This apparently leads to formation of
chimeric ribosomes composed of rRNA molecules
originating from different parents. We speculate that
epigenetic silencing and rDNA rearrangements gen-
erate another layer of variation in multi-molecule
ribosomal complexes which may contribute to the
evolutionary success of allopolyploids.

S.58.6 Evolving
together: Cassandra
retrotransposons gradually
mirror promoter mutations
of the 5S rRNA genes

Sophie Maiwald¹, Ludwig Mann¹, Sònia Garcia² and Tony Heitkam¹,³

1 Faculty of Biology, Technische Universität Dresden, Dresden, Germany. 2 Institut Botànic de Barcelona (CSIC), Barcelona, Catalonia, Spain. 3 Institute of Biology, NAWI Graz, Karl-Franzens-Universität, Graz, Austria

The 5S rRNA genes are among the most conserved
nucleotide sequences across all species. Similar to
the 5S preservation we observe the occurrence of
5S-related non-autonomous retrotransposons, so-
called Cassandras. Cassandras harbor highly con-
served 5S rDNA-related sequences within their long
terminal repeats (LTRs), advantageously providing
them with the 5S internal promoter. However, the dy-
namics of Cassandra retrotransposon evolution in
the context of 5S rRNA gene sequence information
and structural arrangement are still unclear, espe-
cially: 1) do we observe repeated or gradual domes-
tication of the highly conserved 5S promoter by Cas-
sandras and 2) do changes in 5S organization such
as in the linked 35S-5S rDNA arrangements impact
Cassandra evolution? Here, we show evidence for
gradual co-evolution of Cassandra sequences with
their corresponding 5S rDNAs. To follow the impact
of 5S rDNA variability on Cassandra TEs, we investi-
gate the Asteraceae family where highly variable 5S
rDNAs, including 5S promoter shifts and both linked
and separated 35S-5S rDNA arrangements have
been reported. Cassandras within the Asteraceae
mirror 5S rDNA promoter mutations of their host ge-
nome, likely as an adaptation to the host's specific
5S transcription factors and hence compensating
for evolutionary changes in the 5S rDNA sequence.
Changes in the 5S rDNA sequence and in Cassan-
dras seem uncorrelated with linked/separated rDNA
arrangements. We place all these observations into

the context of angiosperm 5S rDNA-Cassandra evo-
lution, discuss Cassandra's origin hypotheses (sin-
gle or multiple) and Cassandra's possible impact
on rDNA and plant genome organization, giving new
insights into the interplay of ribosomal genes and
transposable elements.

S.58.7 5S and 45S rDNA monomer organization: lengths, variation, and interruption in tandem arrays from Musaceae species

Pat Heslop-Harrison¹,², Qing Liu², Ziwei Wang², Trude Schwarzacher¹,²

1 University of Leicester, Leicester, UK. 2 South China
Botanical Garden, Guangzhou, China

Long, single-molecule DNA sequencing shows the
organization and structures of rDNA monomers in
tandem repeats. Short reads of both 5S and 45S
rDNA collapse the arrays during assembly, while old-
er BAC sequences suffer from chaemerism and as-
sembly artefacts. Far from being a continuous array
of monomers, we find short deletions, insertions or
interruptions in the arrays. Full-length retroelements
are found at variable points within some 45S and 5S
monomers in the arrays, and there are occasion-
al insertions of uncharacterized sequences. Within
monomers, both deletions and short duplications
are found. Similar rearrangements have been found
in multiple, non-identical, reads, giving evidence for
homogenization through unequal crossing-over
(and hence duplication of segments of the arrays).
The 'starts' of the arrays have been characterized
with flanking sequences. Musaceae provides a good
model for the comparative study of the rDNA arrays,
with long reads available from multiple species,
variable chromosome numbers and evolutionary
movement of rDNA between chromosomes, inde-
pendent of other genes. The rDNA is very variable
between species, many with one pair sites of 45S
rDNA, representing 1% of all the DNA, to Musa beccarii
with 3 sites and 5% of the DNA. Monomer lengths are
also variable, with the typical length around 400bp
found for most 5S monomers but 1056bp in Ensete.
The detailed characterization of the arrays shows
evolutionary mechanisms and diversity of the ribo-
somal DNA arrays. Further information and referenc-
es are given at www.molcyt.com.