bluuebunny/crossref_metadata_2025 huggingface dataset:
Phylogeny of Capparaceae and Brassicaceae based on chloroplast sequence data
Authors: Hall Jocelyn C. , Sytsma Kenneth J. , Iltis Hugh H.
Published: February 2008

Capparaceae and Brassicaceae have long been known to be closely related families, with the monophyly of Capparaceae more recently questioned. To elucidate the relationship between Brassicaceae and Capparaceae as well as to address infrafamilial relationships within Capparaceae, we analyzed sequence variation for a large sampling, especially of Capparaceae, of these two families using two chloroplast regions, trnL‐trnF and ndhF. Results of parsimony and likelihood analyses strongly support the monophyly of Brassicaceae plus Capparaceae, excluding Forchhammeria, which is clearly placed outside the Brassicaceae and Capparaceae clade and suggest the recognition of three primary clades—Capparaceae subfamily (subf.) Capparoideae, subf. Cleomoideae, and Brassicaceae. Capparaceae monophyly is strongly contradicted with Cleomoideae appearing as sister to Brassicaceae. Two traditionally recognized subfamilies of Capparaceae, Dipterygioideae and Podandrogynoideae, are embedded within Cleomoideae. Whereas habit and some fruit characteristics demarcate the three major clades, floral symmetry, stamen number, leaf type, and fruit type all show homoplasy. Clades within Capparoideae show a biogeographical pattern based on this sampling. These results are consistent with several alternative classification schemes.
Developmental morphology and structural homology of corolla‐androecium synorganization in the tribe Amorpheae (Fabaceae: Papilionoideae)
Authors: McMahon Michelle , Hufford Larry
Published: February 2008

Comparative developmental morphology was used to assess structural homology of flowers in Dalea, Marina, and Psorothamnus of the tribe Amorpheae (Fabaceae: Papilionoideae). Dalea, Marina, and some species of Psorothamnus have an unusual petal‐stamen synorganization (stemonozone) in which free petals are inserted on a region that is continuous with fused stamen filaments. Developmental studies of these three genera demonstrated similarity during organogenesis. Zonal growth results in several synorganized regions, including the stemonozone of Dalea, Marina, and some Psorothamnus. Psorothamnus species that lack a stemonozone have fused stamens and free petals inserted on the hypanthium, as in most other papilionoid legumes. We concluded that the stemonozone is not strictly homologous to either androecium or receptacle, but that it is the product of a modified androecial developmental program. In the prairie clover daleas, petaloid structures positioned between the stamens have been variously interpreted as petals or as staminodes; we infer that they have an extreme form of the daleoid stemonozone, on which five petals (no staminodes) and five stamens are inserted. Assessing structural homology of these flowers allows us to characterize accurately daleoid morphology for evolutionary studies in the tribe Amorpheae.
The transition to gender dimorphism on an evolutionary background of self‐incompatibility: an example from Lycium (Solanaceae)
Authors: Miller Jill S. , Venable D. Lawrence
Published: February 2008

Populations of three North American species of Lycium (Solanaceae) are morphologically gynodioecious and consist of male‐sterile (i.e., female) and hermaphroditic plants. Marked individuals were consistent in sexual expression across years and male sterility was present throughout much of the species' ranges. Controlled pollinations reveal that L. californicum, L. exsertum, and L. fremontii are functionally dioecious. Fruit production in females ranged from 36 to 63%, whereas hermaphrodites functioned essentially as males. Though hermaphrodites were mostly male, investigation of pollen tube growth reveals that hermaphrodites of all dimorphic species were self‐compatible. Self‐fertilization and consequent inbreeding depression are commonly invoked as important selective forces promoting the invasion of male‐sterile mutants into cosexual populations. A corollary prediction of these models is that gender dimorphism evolves from self‐compatible ancestors. However, fruit production, seed production, and pollen tube number following outcross pollination were significantly higher than following self‐pollination for three diploid, cosexual species that are closely related to the dimorphic species. The data presented here on incompatibility systems are consistent with the hypothesis that polyploidy disrupted the self‐incompatibility system in the gynodioecious species leading to the evolution of gender dimorphism.
Triuridaceae fossil flowers from the Upper Cretaceous of New Jersey
Authors: Gandolfo María A. , Nixon Kevin C. , Crepet William L.
Published: February 2008

We report here on a series of fossil flowers exhibiting a mosaic of characters present in the extant monocot family Triuridaceae. Phylogenetic analyses of morphological data from a broad sample of extant monocots confirm the affinities of the fossils with modern Triuridaceae. The fossil flowers were collected from outcrops of the Raritan Formation (Upper Cretaceous, ∼90 million years before present), New Jersey, USA. These are the oldest known unequivocal monocot flowers. Because other reports of “earliest” monocots are all based on equivocal character suites and/or ambiguously preserved fossil material, the Triuridaceae fossils reported here should also be considered as the oldest unequivocal fossil monocots. Flowers are minute and unisexual (only male flowers are known); the perianth is composed of six tepals, lacking stomata. The unicyclic androecium is of three stamens with dithecal, monosporangiate, extrorse anthers that open by longitudinal slits. The endothecium has U‐shaped type thickenings. Pollen grains are monosulcate. The triurid fossil flowers can be separated into three distinctive species. On the basis of phylogenetic analyses of morphological characters, the fossil taxa nest within the completely saprophytic achlorophyllous Triuridaceae supporting the interpretation that the extinct plants were also achlorophyllous and saprophytic. If so, this represents the earliest known fossil occurrence of the saprophytic/mycotrophic habit in angiosperms.
Phylogeny of the Macaronesian endemic Crambe section Dendrocrambe (Brassicaceae) based on internal transcribed spacer sequences of nuclear ribosomal DNA
Authors: Francisco‐Ortega Javier , Fuertes‐Aguilar Javier , Kim Seung‐Chul , Santos‐Guerra Arnoldo , Crawford Daniel J. , Jansen Robert K.
Published: February 2008

The 14 species of Crambe L. sect. Dendrocrambe DC. (Brassicaceae) form a monophyletic group endemic to the Canary and Madeira archipelagos. Both parsimony and maximum likelihood analyses of sequence data from the two internal transcribed spacer regions of nuclear ribosomal DNA were used to estimate phylogenetic relationships within this section. These analyses support the monophyly of three major clades. No clade is restricted to a single island, and therefore it appears that inter‐island colonization has been the main avenue for speciation in these two archipelagos. The two species endemic to Fuerteventura (C. sventenii) and Madeira (C. fruticosa) comprise a clade, providing the first evidence for a floristic link between the Eastern Canary Islands and the archipelago of Madeira. Both maximum likelihood and weighted parsimony analyses show that this clade is sister to the two other clades, although bootstrap support for this relationship is weak. Parsimony optimizations of ecological zones and island distribution suggest a colonization route from the low‐altitude areas of the lowland scrub toward the high‐elevation areas of the laurel and pine forests. In addition, Tenerife is likely the ancestral island for species endemic to the five westernmost islands of Gran Canaria, La Gomera, El Hierro, La Palma, and Tenerife.
Enantiostyly in Wachendorfia (Haemodoraceae): the influence of reproductive systems on the maintenance of the polymorphism
Authors: Jesson Linley K. , Barrett Spencer C. H.
Published: February 2008

Enantiostyly is a form of directional asymmetry in plants in which the style is deflected away from the main axis of the flower, either to the left or right side. In Wachendorfia (Haemodoraceae), a small genus of insect‐pollinated geophytes restricted to the Cape Province of South Africa, populations are usually polymorphic for asymmetry. Here we investigate dimorphic enantiostyly in the four species of Wachendorfia to determine whether variation in their reproductive systems influences the maintenance of this genetic polymorphism. Experimental field pollinations of W. paniculata and W. thyrsiflora indicated higher fertility for cross‐ than for self‐pollinations, whereas in W. brachyandra, these types of pollination produced similar levels of fertility. Outcrossing rates were highest in W. paniculata (t = 0.78–0.98), with W. brachyandra (t = 0.39–0.79) and W. thyrsiflora (t = 0.76) exhibiting mixed mating systems. Outcrossing rates in two populations of W. parviflora varied from mixed mating (t = 0.61) to predominant selfing (t = 0.07). Population style‐morph ratios ranged from 1 : 1 in outcrossing W. paniculata to monomorphism in selfing W. parviflora and clonal W. thyrsiflora. In W. brachyandra, a species with delayed selfing, morph ratios were usually biased. The maintenance of enantiostyly in Wachendorfia appears to be strongly influenced by levels of disassortative mating and the balance between sexual and clonal recruitment.
Vascular architecture and patchy nutrient availability generate within‐plant heterogeneity in plant traits important to herbivores
Authors: Orians Colin M. , Ardón Marcelo , Mohammad Basma A.
Published: February 2008

Within‐plant heterogeneity in growth, morphology, and chemistry is ubiquitous, and is commonly attributed to differences in tissue age, light availability, or previous damage by herbivores. Although these factors are important, we argue that plant vascular architecture is an underappreciated determinant of heterogeneity. Vascular architecture can restrict the transport of resources (nutrients, photosynthate, hormones, etc.) to within specific sectors of the plant: this is referred to as sectoriality. Although studies have documented sectoriality in the transport of isotopes and dyes from roots to shoots, the ecological consequences of this sectoriality remain poorly understood. We tested the hypothesis that spatial variation in belowground nutrient availability combined with sectorial transport results in localized “fertilization” of aboveground plant parts and generates heterogeneity in traits important to herbivores. Our split‐root experiments with tomato (Lycopersicon esculentum Mill) clearly demonstrate that fertilization to isolated lateral roots generates heterogeneity in leaf morphology, phenolic chemistry, and side‐shoot growth. Specifically, leaflets with direct connections to these lateral roots were larger and had lower levels of rutin and chlorogenic acid than did leaflets in other sectors lacking direct vascular connections. Moreover, side‐shoot production was greater in the connected sectors. We discuss the implications of this heterogeneity for plant–herbivore interactions.
Phylogenetic relationships in the Gesnerioideae (Gesneriaceae) based on nrDNA ITS and cpDNA trnL‐F and trnE‐T spacer region sequences
Authors: Zimmer Elizabeth A. , Roalson Eric H. , Skog Laurence E. , Boggan John K. , Idnurm Alexander
Published: February 2008

The Gesnerioideae includes most of the New World members of the Gesneriaceae family and is currently considered to include five tribes: Beslerieae, Episcieae, Gesnerieae, Gloxinieae, and Napeantheae. This study presents maximum parsimony and maximum likelihood phylogenetic analyses of nuclear ribosomal DNA internal transcribed spacer regions (ITS), and the chloroplast DNA trnL intron, trnL‐trnF intergenic spacer region, and trnE‐trnT intergenic spacer region sequences. The ITS and cpDNA data sets strongly support the monophyly of a Beslerieae/Napeantheae clade; an Episcieae clade; a Gesnerieae clade; a Gloxinieae clade minus Sinningia, Sinningia relatives, and Gloxinia sarmentiana; and a Sinningia/Paliavana/Vanhouttea clade. This is the first study to provide strong statistical support for these tribes/clades. These analyses suggest that Sinningia and relatives should be considered as a separate tribe. Additionally, generic relationships are explored, including the apparent polyphyly of Gloxinia. Chromosome number changes are minimized on the proposed phylogeny, with the exception of the n = 11 taxa of the Gloxinieae. Scaly rhizomes appear to have been derived once in the Gloxinieae sensu stricto. The number of derivations of the inferior ovary is unclear: either there was one derivation with a reversal to a superior ovary in the Episcieae, or there were multiple independent derivations of the inferior ovary.
Correlated variation in microtubule distribution, callose deposition during male post‐meiotic cytokinesis, and pollen aperture number across Nicotiana species (Solanaceae)
Authors: Ressayre Adrienne , Raquin Christian , Mignot Agnès , Godelle Bernard , Gouyon Pierre‐Henri
Published: February 2008

In most flowering plants, a single cytokinesis follows the two meiotic divisions during pollen‐grain ontogeny. Aperture pattern (i.e., aperture number and distribution on pollen surface) ontogeny could be linked to the processes ensuring the apportionment of the cytoplasm to the four microspores.

This apportionment is achieved by radial arrays of microtubules organized around the nuclei. The cleavage planes are defined in the overlapping regions of opposing arrays extending from different nuclei. We followed the establishment of these arrays in two different lines of plants belonging to the genus Nicotiana that produce pollen grains with different aperture numbers. Different distributions of the microtubules have been observed, which can be interpreted as resulting from variation in the interactions between nuclei; these distributions appear to be correlated with aperture number.

As a consequence, we propose that simultaneous cytokinesis allows the formation of multiple pollen morphologies. This mechanism is consistent with aperture number distribution within angiosperms and provides clues to help our understanding of the evolution of aperture number.
Effects of crossing distance and genetic relatedness on pollen performance in Alstroemeria aurea (Alstroemeriaceae)
Authors: Souto Cintia P. , Aizen Marcelo A. , Premoli Andrea C.
Published: February 2008

Prezygotic barriers may represent effective mechanisms to avoid the deleterious effects of inbreeding. This study reports the existence of distance‐dependent prezygotic barriers in self‐compatible Alstroemeria aurea, a clonal herb native to temperate forests of the southern Andes. We analyzed pollen germination and tube growth as indicators of donor–recipient affinity using crossing distances of 1, 10, and 100 m. We used allozyme electrophoresis to determine the actual genetic relatedness between donor and recipient ramets. Pollen germination was not affected by distance between mates, but the number of pollen tubes reaching the base of the style increased strongly with distance between donor and recipient. This pattern was related to an increase in genetic dissimilarity with distance between mates. In contrast, pollen tube–style interactions did not change with distance when we restricted analysis to individuals at different distances that appeared to be genetically identical. This test implied genetic dissimilarity as the critical factor affecting pollen performance. We propose that the existence of prezygotic barriers might contribute to the high degree of genetic mixing exhibited by some clonal species.
Population genetics ofIntsia palembanica(Leguminosae) and genetic conservation of Virgin Jungle Reserves in Peninsular Malaysia
Authors: Lee Soon‐Leong , Ng Kevin K.‐S. , Saw Leng‐Guan , Norwati Adnan , Salwana M. H. Siti , Lee Chai‐Ting , Norwati Muhammad
Published: February 2008

A field survey of Virgin Jungle Reserve (VJR) compartments in Peninsular Malaysia allowed us to identify six populations ofIntsia palembanicafor this study. These were Pasoh Forest Reserve (FR) (Pasoh), Sungai Lalang FR (Lalang), Bukit Lagong FR (Lagong), Bubu FR (Bubu), Bukit Kinta FR (Kinta), and Bukit Perangin FR (Perangin). About 40 adult individuals were sampled in each population. In addition, progeny arrays were collected from nine mother plants at Lagong for a mating system study. A total of nine allozymes, encoded by 14 putative gene loci, were consistently resolved inI. palembanica. The mating system study showed that the species exhibited a mixed‐mating system, with multilocus outcrossing rate of 0.766. The levels of diversity were comparably high (mean number of alleles per polymorphic locus = 2.4, mean effective number of alleles per polymorphic locus = 1.64, and mean expected heterozygosity (He) = 0.242), and the majority of the diversity was partitioned within population (GST= 0.040 andFST= 0.048). Significant levels of inbreeding were detected in Bubu and Perangin. Probability tests of recent effective population size reduction using the Infinite Allele Model showed the occurrence of genetic bottlenecks on Lalang and Kinta. Two genetically unique populations (Pasoh and Perangin) were inferred using jackknife analysis. By using the neutral mutation rates, effective population size (Ne) to maintain theHewas 80–800 000 individuals. A simulation study based on pooled samples, however, circumscribed theNeto 200 and 210 individuals. Implications of the study for managing the species and the VJRs are discussed.
Habitat divergence between a homoploid hybrid sunflower species,Helianthus paradoxus(Asteraceae), and its progenitors
Authors: Welch Mark E. , Rieseberg Loren H.
Published: February 2008

The diploid hybrid speciesHelianthus paradoxusis restricted to salt marshes with sodium concentrations that exceed those found in the habitats of its progenitors,H. annuusandH. petiolaris. The observed association with saline habitats has led to the hypothesis thatH. paradoxusis more salt tolerant than its progenitors. This hypothesis was tested by growing all three species in three NaCl treatments (0 mmol/L, 100 mmol/L, and 200 mmol/L).Helianthus paradoxustreated with NaCl was found to be more than five times as fit, in terms of biomass and survivorship, than its progenitors. Selection for salt tolerance in early generation hybrids may have contributed to the formation ofH. paradoxusbecause theory predicts that homoploid hybrid speciation is feasible even when selection favoring hybrid genotypes is much weaker. Additionally, we show thatH. paradoxusis significantly different from its parental species for several traits that often distinguish salt‐tolerant species and suggest a mechanistic basis for the elevated salt tolerance expressed byH. paradoxus.
Factors responsible for Honckenya peploides (Caryophyllaceae) and Leymus mollis (Poaceae) spatial segregation on subarctic coastal dunes
Authors: Gagné Jean‐Michel , Houle Gilles
Published: February 2008

Low water and nutrient availability and significant sand movement, salt spray, and soil salinity are typical of coastal dunes. These conditions are generally unfavorable for the various life stages of plants and especially for seedlings. However, the intensity of these stresses decreases landward, even over short distances, with significant effects on community composition. On coastal dunes in subarctic Québec, Canada, Honckenya peploides (Caryophyllaceae) colonizes the upper beach where it forms small mounds called embryo dunes. Leymus mollis (Poaceae) is mostly restricted to the foredune; however, a few individuals successfully establish on the upper beach, particularly on embryo dunes. We hypothesized that this differential distribution is associated with differences in the tolerance of the two species' seedlings to physical stresses. Honckenya peploides and L. mollis seedling tolerance to sand burial, salt spray, soil salinity, and nutrient and water availability was assessed in greenhouse experiments. Unexpectedly, our results showed that tolerance to sand burial, salt spray, and soil salinity was lower for H. peploides than for L. mollis. If seeds are available and seedlings tolerate the conditions prevailing on the upper beach well, why are mature L. mollis individuals rare in this habitat? We suggest that massive abrasion events (e.g., violent storm waves and ice thrust) restrict the presence of the species on the upper beach.
Chloroplast DNA evidence for the roles of island colonization and extinction in Tolpis (Asteraceae: Lactuceae)
Authors: Moore Michael J. , Francisco‐Ortega Javier , Santos‐Guerra Arnoldo , Jansen Robert K.
Published: February 2008

Tolpis consists of ∼13 species native to Africa, Europe, and Macaronesia, with at least one species endemic to each of the four major archipelagos of the Azores, Madeira Islands, Canary Islands, and Cape Verde Islands. All but two of these species develop woody stems by maturity. Chloroplast DNA restriction site variation was analyzed for all species of Tolpis and four outgroups in order to understand the patterns of island colonization and evolution of woodiness in this genus. Parsimony analyses revealed a strongly supported monophyletic Tolpis. Within the genus, the following three well‐supported groups were detected: all species from the Canary Islands and Cape Verde Islands, both Azorean species, and both continental species. The Canary Island/Cape Verde clade was sister to the two continental species, and the Azorean clade was sister to this group. The two Madeiran species of Tolpis occupied the basalmost positions within the genus. When biogeography was mapped onto this phylogeny, nine equally parsimonious reconstructions (five steps each) of dispersal history were detected, which fell into two groups: eight reconstructions implied that Tolpis colonized Madeira from the continent, followed by continental extinction and subsequent continental recolonization, while one reconstruction implied that Tolpis colonized Macaronesia four times. Two of the reconstructions involving continental extinction required the least amount of overall dispersal distance. The cpDNA phylogeny also suggests that woodiness arose in the common ancestor of all extant Tolpis, followed by two independent reversals to an herbaceous habit. Assuming that one of the eight reconstructions favoring continental extinction and recolonization is true, our results suggest that Tolpis may represent the first documented example of a woody plant group in Macaronesia that has recolonized the mainland in herbaceous form.
Aristolochia spp. (Aristolochiaceae) pollinated by flies breeding on decomposing flowers in Panama
Authors: Sakai Shoko
Published: February 2008

This study presents breeding and pollination systems of Aristolochia maxima and A. inflata in a seasonal tropical forest of Panama. Aristolochia is the most diverse genus of Aristolochiaceae, with ∼120 species distributed throughout the tropics and subtropics. All the Aristolochia species studied so far are pollinated by saprophagous flies of different families, which are presumably deceived by floral odor. Flowers of many species have trap‐and‐release mechanisms. The flowers attract and imprison pollinators during the female stage first day of flowering and release them after anther dehiscence. Pollination systems of A. maxima and A. inflata are different from those of other Aristolochia in lacking trap mechanisms. Furthermore, the pollinators oviposit in the flowers, and their larvae grow on the fallen, decaying flowers on the ground. Therefore, the plants have a mutualistic relationship with their pollinators. Self‐compatible A. inflata is pollinated by Megaselia sakaiae (Phoridae, Diptera). The pollinator may be specialized to Aristolochia flowers, which is the only substrate for larval development. On the other hand, self‐incompatible A. maxima is pollinated by Drosophila spp. (Drosophilidae, Diptera), which utilize Aristolochia flowers as a breeding site only occasionally. This pollination mutualism might have evolved from deceit pollination.
A diverse assemblage of Anacardiaceae from Oligocene sediments, Tepexi de Rodriguez, Puebla, Mexico
Authors: Ramírez José L. , Cevallos‐Ferriz Sergio R. S.
Published: February 2008

Among the plants collected from the Pie de Vaca Formation of the Oligocene, of Tepexi de Rodríguez, Puebla, México are five plants of Anacardiaceae, Haplorhus medranoensis, Rhus toxicodendron, Rhus sp., Comocladia intermedia, and Pistacia marquezii represented by their leaves and/or leaflets. The past and present diversity and geographic distribution of one of these genera, Rhus, demonstrate its capability to adapt and diversify in a wide variety of environments. Leaf architecture characters of this taxon overlap with those of other genera in the family, suggesting a high degree of phenotypic plasticity. The presence in the Pie de Vaca Formation of a type of Pistacia with leaf architecture characters similar to those of Asian plants further supports a long history of exchange between low‐latitude North America and Asia. Links between low‐latitude North and South America and the Caribbean are suggested by the presence of Comocladia and Haplorhus. Whereas Comocladia highlights the long history of regional endemics in the area, Haplorhus, today an endemic monotypic genus of Peru, suggests exchange mechanisms between North and South America. The morphologic characters of these taxa, and those of Pseudosmodingium (Anacardiaceae), some Rosaceae, Leguminosae, and Berberidaceae, suggest that the Pie de Vaca community was established and evolved in harsh environmental conditions. The Pie de Vaca flora thus provides significant new insights into the biogeographic relationships of the low latitude vegetation of North America.
Karyotypic studies in Turnera sidoides complex (Turneraceae, Leiocarpae)
Authors: Solís Neffa Viviana G. , Fernández Aveliano
Published: February 2008

Turnera sidoides, with the most southerly distribution of all Turnera species in America, is a complex of obligately outcrossing perennial herbs. Karyotypes of the five subspecies of T. sidoides (x = 7) are described for the first time utilizing root‐tip mitotic metaphases. Different ploidy levels were found for all of the subspecies, ranging from diploid to octoploid. The results obtained, coupled with available meiotic and preliminary biosystematic data, support the hypothesis of autopolyploidy within this species complex. Although detailed karyotype analysis shows a high degree of intraspecific uniformity, subspecies may be differentiated by the number, type, and position of satellites, suggesting that chromosome rearrangements may also be involved in the karyotypic evolution of T. sidoides. Karyotype data, coupled with morphological and anatomical features, suggest the removal of T. sidoides from series Leiocarpae.
Molecular mapping of the fasciation mutation in soybean, Glycine max (Leguminosae)
Authors: Karakaya H. Caglar , Tang Yuhong , Cregan Perry B. , Knap Halina T.
Published: February 2008

The spontaneous fasciation mutation generates novel developmental diversity in cultivated soybean, Glycine max (L.) Merrill. An increased apical dominance in the mutant inhibits axillary buds, causes a branchless phenotype, and restricts reproduction to shoot apices. The fasciation mutation is encoded by a recessive (f) allele at a single locus. The mutation, despite its importance in soybean development, has no locus assignment on previously reported molecular maps of soybean. A population of 70 F2 progeny was derived from a cross between ‘Clark 63’ and the fasciation mutant. More than 700 molecular markers (amplified restriction fragment length polymorphisms [AFLPs], random amplified polymorphic DNAs [RAPDs], restriction fragment length polymorphisms [RFLPs], and simple sequence repeats [SSRs]) were used in mapping of the fasciation phenotype. Twenty linkage groups (LGs) corresponding to the public soybean molecular map are represented on the Clark 63 × fasciation mutant molecular map that spans 3050 centimorgans (cM). The f locus was mapped on LG D1b+W and linked with two AFLPs and four SSR markers (Satt005, Satt141, Satt600, and Satt703). No linkage was found between the f locus and several cDNA polymorphic loci between the wild type and the mutant. The known map position of the f locus and demonstration of the mutant phenotype from early postembryonic throughout reproductive stages provide an excellent resource for investigations of molecular mechanisms affecting soybean ontogeny.
Genetic variation at allozyme and RAPD markers in Pinus longaeva (Pinaceae) of the White Mountains, California
Authors: Lee Seok‐Woo , Ledig F. Thomas , Johnson David R.
Published: February 2008

We compared genetic diversity estimated from allozymes and from random amplified polymorphic DNA (RAPDs) in a sample of 210 Great Basin bristlecone pines (Pinus longaeva Bailey) from three groves in the White Mountains, California, USA. The White Mountains are the most westerly extension of bristlecone pine and home to the oldest known living trees. We assayed two forks of each tree to determine whether they originated from multiple seed caches of the Clark's nutcracker. Despite the limited and fragmented distribution of bristlecone pine, its level of genetic diversity was comparable to that of other pines, but lower than that reported for eastern populations of Great Basin bristlecone pine. Twenty‐six of 36 allozymes were polymorphic (p95 = 38.9%; p = 63.0%), with observed heterozygosity (Ho) of 0.122 and expected heterozygosity (He) of 0.134. The proportion of the total variation among populations (GST) was only 0.011. The high proportion of trees with multiple stems was not due to germination in seed caches; only six of 210 forked trees had multiple allozyme genotypes. Of the 42 RAPD loci scored, 27 were monomorphic. Genetic diversity for RAPDs was nearly the same as that for allozymes (p95 = 34.1%, He = 0.130). However, the estimates of diversity and differentiation were much higher (He = 0.321, GST = 0.039) after excluding monomorphic loci.
Application of methyl jasmonate on Picea abies (Pinaceae) stems induces defense‐related responses in phloem and xylem
Authors: Franceschi Vincent R. , Krekling Trygve , Christiansen Erik
Published: February 2008

Application of 100 mmol/L methyl jasmonate (MJ) to the intact bark of 30‐yr‐old Norway spruce induced anatomical reactions related to defense. Within 30 d, a single MJ treatment induced swelling of existing polyphenolic parenchyma cells (PP cells) and an increase in their phenolic contents and formation of additional PP cells and of traumatic resin ducts (TDs) at the cambial zone. These changes occurred up to 7 cm away from the application zone. Treatment enhanced resin flow and increased resistance to the blue‐stain fungus, Ceratocystis polonica. Methyl jasmonate application to the oldest internode of 2‐yr‐old saplings also induced TD formation, and, more surprisingly, TDs were formed in the untreated internode. Traumatic ducts were not formed in branches, ruling out an effect of volatile MJ on the upper internode. Methyl jasmonate application never gave rise to a hypersensitive response, cell death, tissue necrosis, or wound periderm, indicating the amount of MJ transported across the periderm was very low relative to the application concentration. This is the first report of a single compound giving rise to major cellular features related to acquired resistance and previously shown to be induced by wounding, fungal infection, and bark beetles in Norway spruce.
Clonal structure and hybrid susceptibility to a smut pathogen in microscale hybrid zones of northern wetlandCarex(Cyperaceae)
Authors: McIntire Eliot J. B. , Waterway Marcia J.
Published: February 2008

Interspecific hybrid taxa, especially those with the potential for clonal spread, may play important roles in community dynamics and plant–pathogen interactions. This study combines the mapping of clonal structure for two rhizomatous sedges (Carex limosa,C. rariflora) and their nearly sterile interspecific hybrid with an investigation of the relationship between these taxa and a nonsystemic floral smut pathogen (Anthracoidea limosa) in six subarctic fens in Nouveau‐Québec, Canada. We used allozyme polymorphisms in 14 of 18 putative loci to confirm hybrid identification and to distinguish among genotypes for mapping. The incidence ofA. limosawas 5–20 times greater on hybrids than on parental taxa across all sites at two spatial scales (intensive extent = 10.5 m2, extensive extent = entire fens). Spatial autocorrelation was detected in smut incidence; however, its statistical removal did not alter the strong association between hybrids and smut infection. Smut incidence on bothC. limosaand hybrids was greater when they were growing in areas of high hybrid density. Our study provides evidence that disease can help maintain boundaries between species. We suggest explanations for hybrid susceptibility and provide evidence for a model in which hybrids act as a source for reinfection for all three taxa during subsequent years.
Madagasikaria (Malpighiaceae): a new genus from Madagascar with implications for floral evolution in Malpighiaceae
Authors: Davis Charles C.
Published: February 2008

Madagasikaria andersonii is described here as a new genus and species of Malpighiaceae from Madagascar. The phylogenetic placement of Madagasikaria was estimated by using combined data from ndhF and trnL‐F chloroplast sequences and phytochrome (PHYC) and ITS nuclear sequences. It forms a strongly supported clade with the Malagasy endemic genera Rhynchophora and Microsteira. Despite nearly identical floral morphology among species in this clade (here called the madagasikarioid clade), these genera are easily distinguishable on the basis of their fruits. The schizocarpic fruits of Madagasikaria have distinctive mericarps. Each mericarp has a lateral wing, which completely encircles the nut, and a peculiar dorsal wing, which folds over on itself. The morphology of this fruit suggests that the homology of the unusual wing in Rhynchophora is lateral in nature and represents a reduced wing similar to the lateral wing in Madagasikaria. Taxa in the madagasikarioid clade all appear to be morphologically androdioecious and functionally dioecious, producing both staminate and “bisexual” (i.e., functionally carpellate) individuals. This condition appears to be exceedingly rare in flowering plants and has important implications for floral evolution within Malpighiaceae. Neotropical Malpighiaceae are pollinated by specialized oil‐collecting anthophorine bees of the tribe Centridini and exhibit highly conserved floral morphology despite tremendous diversity in fruit morphology and habit. These oil‐collecting bees are absent from the paleotropics, where most members of the Malpighiaceae lack both the oil glands and the typical floral orientation crucial to pollination by neotropical oil‐collecting bees. The madagasikarioids represent one shift from the neotropical pollination syndrome among Old World Malpighiaceae.
Tetrad pollen formation in Annona (Annonaceae): proexine formation andbinding mechanism
Authors: Tsou Chih‐Hua , Fu Yu‐Lan
Published: February 2008

Meiotic tetrads of Annona glabra and A. montana build up a well‐developed proexine (protectum, probaculum, and pronexine) at the proximal side but only a thin pronexine at the distal side during the tetrad stage. The callosic envelope is only partially digested by the end of tetrad stage. The remaining, undigested part is composed of the intersporal mass and thin peripheral layers, and the latter is conjunct with the distal pronexine of the microspore. In this remaining callosic structure celluloses are also present. Later on, due to the continuous slow decomposition of this callose‐cellulose structure and microspore expansion, microspores break up the callose‐cellulose envelope. Because all the four microspores are bound together by the callose‐cellulose structure, they move out of the chamber in rotation. Eventually the thin pronexine is pulled toward the center of the tetrad and the well‐developed proexine becomes the distal wall. These descriptions of the partial digestion of callosic envelope, the transformation from a callose‐cellulose structure to the binding system of tetrad pollen, and microspore rotation in Annona are unusual in the angiosperms.
Genetic variation and population structure in central and isolated populations of balsam fir,Abies balsamea(Pinaceae)
Authors: Shea Kathleen L. , Furnier Glenn R.
Published: February 2008

Genetic variation and spatial genetic structure in balsam fir (Abies balsamea) were examined in two isolated populations in Iowa and Minnesota thought to be paleorefugia and in two ecologically central populations in old‐growth forests of Upper Michigan. Overall levels of genetic variability at 22 allozyme loci were lower than that found in most conifer species (Hovalues ranged from 0.005 in the isolated populations to 0.025 in the central populations). The meanFISvalue (0.154) was larger than usually found in conifers and suggests moderate levels of inbreeding. The meanFST, an estimate of genetic diversity among populations, was 3.7% of the total diversity, a value lower than the mean for conifers. Nm, the number of migrants per generation, was 6.5, suggesting either some gene flow among populations or a lack of genetic differentiation. Spatial autocorrelation analysis revealed a moderately patchy structure, with gene flow distances of 30–70 m in the central populations and at least 10 m in the isolated populations. The future of the ecologically central populations depends on maintenance of an intact forest mosaic. The low genetic variability in the small, isolated populations suggests that habitat fragmentation has led to a reduction in evolutionary potential and that the future viability of these populations will likely require active management in the face of global climate change.
Different fates of island brooms: contrasting evolution in Adenocarpus, Genista, and Teline (Genisteae, Fabaceae) in the Canary Islands and Madeira
Authors: Percy Diana M. , Cronk Quentin C. B.
Published: February 2008

Analysis of sequence data from the internal transcribed spacers (ITS) and 5.8S region of nuclear ribosomal DNA show that Canarian and Madeiran brooms (Genisteae) of the genera Teline, Adenocarpus, and Genista are related to Mediterranean species and not to species from adjacent parts of Morocco. Each separate colonization of the islands has resulted in contrasting patterns of adaptation and radiation. The genus Teline is polyphyletic, with both groups (the “T. monspessulana group” and the “T. linifolia group”) separately nested within Genista. Genista benehoavensis (La Palma) and G. tenera (Madeira) form, with G. tinctoria of Europe, a single clade characterized by vestigially arillate seeds. The Canarian species of Adenocarpus have almost identical sequence to the Mediterranean A. complicatus and are likely to be the result of island speciation after a very recent colonization event. This Canarian/Mediterranean A. complicatus group is sister to the afrotropical montane A. mannii which is probably derived from an earlier colonization from the Mediterranean, possibly via the Red Sea hills. The independent colonization and subsequent radiation of the two Teline groups in the Canary Islands make an interesting comparison: the phylogenies both show geographical structuring, each with a central and western island division of taxa. Within the “T. monspessulana group” there is some evidence that both continental and Madeiran taxa could be derived from the Canary Islands, although it is likely that near contemporaneous speciation occurred via rapid colonization of the mainland and islands. The finding of two groups within Teline also has implications for patterns of hybridization in those parts of the world where Teline species are invasive; in California members of the T. monspessulana group hybridize readily, but no hybrids have been recorded with T. linifolia which has been introduced in the same areas.
Conservation implications of the reproductive ecology ofAgalinis acuta(Scrophulariaceae)
Authors: Neel Maile C.
Published: February 2008

Reproductive ecology ofAgalinis acutawas investigated by examining potential for self‐fertilization before and at anthesis, reproductive output from outcrossed vs. selfed matings, and effects of browsing, plant size, and conspecific plant density on seed and fruit production. These features of a plant species can provide indirect information pertinent to conservation such as patterns and maintenance of genetic diversity, risk associated with inbreeding depression, and changes in pollinator abundance or effectiveness. The species is self‐compatible, with 97% of selfed flowers setting fruit; pollinators were not required for reproduction. However, seed set in self‐pollinated fruits averaged 17–20% less than that in open‐pollinated fruits. Geitonogamous and facilitated selfing are possible throughout anthesis and autonomous selfing is possible late in anthesis as corollas abscise. Delaying self‐pollination until after outcrossing opportunities likely limits selfing rates and thus reduces risks associated with inbreeding but allows reproduction in absence of pollinators. Supplementing pollen on open‐pollinated flowers yielded no additional seed set over controls. Neither early‐season browsing of primary stems nor conspecific plant density had significant effects on number of fruits per plant, on fruit size, or on number of seeds from open‐pollinated flowers. Currently, reproduction appears to be high (about 2400 seeds/plant), and future risks due to lack of genetic diversity are likely low.
Divergent and reticulate species relationships in Leucaena (Fabaceae) inferred from multiple data sources: insights into polyploid origins and nrDNA polymorphism
Authors: Hughes Colin E. , Bailey C. Donovan , Harris Stephen A.
Published: February 2008

Previous analyses of species relationships and polyploid origins in the mimosoid legume genus Leucaena have used chloroplast DNA (cpDNA) restriction site data and morphology. Here we present an analysis of a new DNA sequence data set for the nuclear ribosomal DNA (nrDNA) 5.8S subunit and flanking ITS 1 and ITS 2 spacers, a simultaneous analysis of the morphology, ITS and cpDNA data sets for the diploid species, and a detailed comparison of the cpDNA and ITS gene trees, which include multiple accessions of all five tetraploid species. Significant new insights into species relationships and polyploid origins, including that of the economically important tropical forage tree L. leucocephala, are discussed. Heterogeneous ITS copy types, including 26 putative pseudogene sequences, were found within individuals of four of the five tetraploid and one diploid species. Potential pseudogenes were identified using two pairwise comparison approaches as well as a tree‐based method that compares observed and expected proportions of total ITS variation contributed by the 5.8S subunit optimized onto branches of one of the ITS gene trees. Inclusion of putative pseudogene sequences in the analysis provided evidence that some pseudogenes in allopolyploid L. leucocephala are not the result of post‐allopolyploidization gene silencing, but were inherited from its putative diploid maternal progenitor L. pulverulenta.
Cryptic goldfields: a molecular phylogenetic reinvestigation of Lasthenia californica sensu lato and close relatives (Compositae: Heliantheae sensu lato)
Authors: Chan Raymund , Baldwin Bruce G. , Ornduff Robert
Published: February 2008

Maximum parsimony analysis of DNA sequence data from the internal and external transcribed spacer (ITS and ETS) regions of 18S–26S nuclear ribosomal DNA and the 3′ trnK intron of chloroplast DNA from over 60 populations of Lasthenia sect. Amphiachaenia yielded a well‐supported tree showing that the most common species of Lasthenia, L. californica sensu lato (s.l.), is not monophyletic. Members of Lasthenia californica s.l. belong to two well‐supported but morphologically cryptic clades. One clade includes members of L. macrantha; the other represents a basally divergent lineage in L. sect. Amphiachaenia. Members of each clade can be diagnosed by pappus morphology and by geographic distribution, except for epappose plants that occur in a broad region of sympatry in central California. Overall diversification in the clade corresponding to L. sect. Amphiachaenia has been accompanied by minimal morphological divergence, which has resulted in previously underappreciated cryptic diversity.
Synchronization of growth, branching and flowering processes in the South American tropical tree Cecropia obtusa (Cecropiaceae)
Authors: Heuret Patrick , Barthélémy Daniel , Guédon Yann , Coulmier Xavier , Tancre Juliette
Published: February 2008

Cecropia obtusa Trécul (Cecropiaceae) is a pioneer species associated with the initial phases of regeneration of tropical South American forests. A comparison of the succession of morphological events associated with each node (inflorescences or branches developed or aborted and underlying internode length) making up the axes of 30 trees helped to establish a link between their architecture and the regularity and synchronicity of their expression of growth, flowering, and branching processes over time on an individual and stand level. For a given individual, new nodes are emitted at the same rate on all the axes, irrespective of their branching order. Flowering and branching alternate, and these processes occur in all the axes of the tree synchronously. On a stand level, flowering and branching occur regularly every 35 nodes or so, which apparently corresponds to an annual rhythm. Under nonlimiting conditions, a single branch tier would be emitted each year, and it is thus possible to determine a posteriori the age of a crown accurately. The merits of the method, the possibility of estimating the age of natural Cecropia obtusa regrowth by observing tree architecture, and the possible applications in the field of ecology are discussed.
Inflorescence diversification in the panicoid “bristle grass” clade (Paniceae, Poaceae): evidence from molecular phylogenies and developmental morphology
Authors: Doust Andrew N. , Kellogg Elizabeth A.
Published: February 2008

Grasses exhibit a great variety of inflorescence forms and these appear homoplasious when mapped onto cladograms. The overall pattern is sufficiently complex that it is difficult to analyze inflorescence evolution. We have reduced the complexity of the problem by examining one group of grasses, the panicoid “bristle clade,” which exhibits a less complex pattern of variation. The clade is morphologically defined by inflorescences bearing both spikelets and sterile bristles and is monophyletic in both morphological and molecular phylogenetic analyses. We have constructed a chloroplast DNA phylogeny of the three main genera, which finds three well‐supported clades, two comprising species placed in Setaria and one of Pennisetum + Cenchrus. In this tree Cenchrus is monophyletic, but both Setaria and Pennisetum are paraphyletic. Developmental morphology of these groups is very similar at early stages. Changes in axis ramification, primordial differentiation, and axis elongation account for most variation in mature inflorescence morphology. Characters derived from comparisons of developmental sequences were optimized onto one of the most parsimonious trees. Most developmental characters were congruent with the molecular phylogeny except for three reversals in the subclade containing S. barbata, S. palmifolia, and two accessions of S. poiretiana. Changes in just a handful of developmental events account for inflorescence evolution in the bristle clade, and similar changes may account for inflorescence diversity in the grasses as a whole.