bluuebunny/crossref_metadata_2025 huggingface dataset:
Chromosomal Variation in Lotus alpinus (Fabaceae)
Authors: O'Donoughue Louise S. , Grant W. F.
Published: February 2005

Abstract An accession of Lotus alpinus Schleich. (2n=2x=12) from Turkey in which B chromosomes have been found was studied morphologically and karyologically. Chromosome numbers were observed in 519 cells from nine plants which all exhibited mixoploidy (2n=11, 12, 12 + 1B, 12 + 2B and over 20). Keel tip color, stem pubescence, and inflorescence size differed from a collection of this species from Switzerland. While the percentage of total lengths of the chromosome complements and the relative chromosome lengths in the two accessions were very similar, the total complement lengths differed considerably (23.14μm Turkey vs. 29.46μm Switzerland). This karyological difference is not considered to be the result of the presence of B chromosomes, but probably the result of hybridization between different genotypes. Aborted seed pods were observed which lent credibility to this hypothesis. Plants of this accession may have arisen as a result of hybridization between Lotus corniculatus and/or L. alpinus as both diploid and tetraploid cytotypes are reported in the Turkey collection for these species. The data would lend support for their hybrid origin.
The Affinities and Relationships of the Japanese Endemic Pseudopyxis (Rubiaceae‐Paederieae)
Authors: Puff Christian
Published: February 2005

Abstract Selected character states of the presumed allies of Pseudopyxis are described, compared and discussed. Particular attention is paid to the fruits and diaspores and their ways of development and differentiation. It is presumed that 1) Pseudopyxis and Serissa are closely allied, that 2) these two genera are, in turn, closely related to Leptodermis and the monotypic Spermadictyon (the latter possibly not generically distinct from the former), that 3) Paederia loosely links up to four mentioned genera, and that 4) the monotypic Aitchisonia stands rather isolated on account of various peculiarities.
Genetic Diversity and Population Structure of Dioscorea tokoro Makino, a Dioecious Climber
Authors: Terauchi Ryohei
Published: February 2005

Abstract Dioscorea tokoro Makino is a herbaceous climber species widespread in East Asia. Genetic structure of a natural population of D. tokoro was examined employing starch gel electrophoresis of allozymes. Genotypes of seven loci were studied for 1,128 individuals. Twenty‐six populations located mainly in the Kinki district of Japan were subgrouped into four large clusters by the geographical distribution of alleles. The D. tokoro population was revealed to contain greater total genetic diversity (HT=0.282) and higher intrapopulational genetic diversity (HS=0.258) than other outcrossing species for which data are available. On the other hand, interpopulational differentiation (GST=0.096) was smaller than in other outcrossers. For the heterozygosity deficiency observed (FIT=0.125), population subdivision (FST=0.096) and inbreeding within the population (FIS=0.067) were revealed to contribute to the same extent. From these F‐statistics, the migration rate among subpopulations and the rate of between‐relative matings were estimated. Overall results on the genetic structure of the D. tokoro population indicated a high gene flow among its subpopulations, and this may be the consequence of its life form as a climber and its habitat in a disturbed environment. During the study, the geographical cline of Pgi allele frequencies was observed. This finding was supposed to be the result of the selection imposed on Pgi by the temperature differences between localities.
Trends for Inbreeding in Polyploid Pteridophytes
Authors: Masuyama Shigeo , Watano Yasuyuki
Published: February 2005

Abstract Previous studies on the sequence of the gametangium formation in homosporous fern gametophytes (Masuyama, 1975a, b) suggested that diploid and polyploid taxa may favor gametophytic crossing and gametophytic selfing, respectively. In this view, intraspecific polyploids of three fern species (Phegopteris decursive‐pinnata, Lepisorus thunbergianus and Pteris dispar) have been investigated for the amount of genetic load or the rate of gametophytic selfing. As expected, a marked contrast of mating systems is found between diploids and tetraploids; the former predominantly undergo gametophytic crossing and the latter predominantly undergo gametophytic selfing. It seems likely that diploid homosporous pteridophytes favor gametophytic crossing with some exceptions favoring gametophytic selfing as a derived condition, whereas polyploid homosporous pteridophytes favor gametophytic selfing predominantly.
Variation in Outcrossing Rates in Eichhornia paniculata: The Role of Demographic and Reproductive Factors*
Authors: Barrett Spencer C. H. , Husband Brian C.
Published: February 2005

Abstract A survey of 32 populations of the self‐compatible, tristylous, aquatic, Eichhornia paniculata (Pontederiaceae), from N. E. Brazil and Jamaica, was undertaken to examine the role of demographic and reproductive factors on variation in outcrossing rate (t), and to investigate the association between t and population genetic structure. Multi‐locus outcrossing rates, estimated using isozyme techniques, varied widely (t̂= 0.002–0.960) among populations and were uniformly distributed across the entire range of t. Sixty percent of variation in t̂ was explained by style morph diversity (E) and the frequency of selfing variants within populations (M). Population size (N) and plant density (d) also accounted for a significant portion of variation in t̂, particularly in Jamaica, where variation in style morph diversity was low.

Outcrossing rates were significantly correlated with the proportion of loci that were polymorphic (P), the average number of alleles per polymorphic loci (Na), the average observed heterozygosity, (Ho), and the inbreeding coefficient (f̂). A strong regional effect was evident in the association of f̂ with P and Na. This largely results from the confounding effect of genetic bottleneck(s) and high levels of self‐fertilization associated with the colonization of Jamaica. Comparisons of f̂ with the equilibrium inbreeding coefficient, (Feq), indicated that outcrossing populations had a significant deficiency of heterozygotes, while selfing populations had an excess. This demonstrates that levels of heterozygosity cannot be accounted for by the mating system alone. Outcrossing rate variation in E. paniculata is controlled by a complex interplay of local demographic and genetic factors. These influences operate within contrasting regional contexts as a result of the different evolutionary histories of populations in N. E. Brazil and Jamaica.
An Application of the Sex Allocation Theory to Arisaema serratum
Authors: Kakehashi Masayuki , Kinoshita Ehchiro
Published: February 2005

Abstract The sex allocation theory based on size‐specific demography is applied to sex change phenomena exhibited by Arisaema serratum, which changes sex expression according to its size. In the evolutionary analysis where adopted strategy correlates with resource level, identifying equal resource level is very important. But directly measured size does not seem to represent the plant's real resource level perfectly. In the analysis presented here, we introduce a new variable that represents the resource level. According to the sex allocation theory, we calculated the transition matrix and other demographic parameters, the stable sex‐and‐size distribution, and reproductive values. The obtained results were: (1) reproductive values generally increased in accordance with size, but in a different manner for different sexes; (2) in the size class where different sex expressions were adopted, reproductive values for the equal resources were the same; and (3) plant individuals seemed to adopt evolutionarily stable strategies. The adaptive nature of the plant is further discussed.
Non‐Random Mating in a Wild Radish, Raphanus sativus
Authors: Marshall Diane L.
Published: February 2005

Abstract When mating is non‐random among several, compatible donors, the fitness of pollen donors, maternal plants, and offspring may be affected. Although this process may be important, it is much less studied than other forms of non‐random mating such as incompatibility and avoidance of inbreeding. Therefore, the amount and consequences of non‐random mating were investigated in greenhouse studies with wild radish, Raphanus sativus. Six compatible donors differed in the number, position, and weight of seeds sired, so mating was non‐random at the level of mate identity. Mate number also affected mating patterns; fruits with more fathers were allocated more resources. This keeps mate number per fruit high. In contrast, other processes appear to keep mate number below the maximum so that mate number per fruit is regulated at an intermediate level. Mate identity had clear consequences as offspring with different fathers were of different sizes after 11 weeks. The effects of mate number on offspring success were less clear. These and other data suggest that non‐random mating among compatible donors is a relatively common process in wild radish. It may occur through mechanisms controlled by the pollen tubes, the maternal plants or the embryos. While this non‐random mating is the raw maternal for sexual selection in plants, whether sexual selection actually occurs and how important it may be is still nuclear.
Origin and Genetic Variation of Agamosporous Ferns1)
Authors: Murakami Noriaki , Iwatsuki Kunio
Published: February 2005

Abstract Two agamosporous fern species, Pteris cretica and Dryopteris yakusilvicola as well as some sexual species related to them were cytologically and enzyme electrophoretically analysed in order to elucidate their genetic variation and its origin. Pteris cretica in Japan has been reported to contain diploid and triploid agamosporous races. Our allozyme data strongly suggested that the agamosporous triploid originated through recurrent hybridization between the diploid agamosporous race of P. cretica and the related sexual species, P. kidoi. Recurrent hybridization with related sexual species can be considered to contribute to increase the genetic variation of this agamosporous species. On the other hand, triploid agamosporous species, D. yakusilvicola was suggested to be of hybrid origin between diploid sexual D. sabaei and the tetraploid sexual race of D. sparsa based on our allozyme data. Moreover, 56 individuals of D. yakusilvicola from various localities which were electrophoretically analyzed showed the same banding pattern. This genotypic uniformity suggests that this species was recently derived through a single hybridization event.
Electrophoretic Study of Taxonomic Relationships in the Saussurea nipponica Complex (Compositae)
Authors: Im Hyoung‐Tak
Published: February 2005

Abstract The Saussurea nipponica complex was examined with enzyme electrophoresis. Earlier morphological evidence suggested that the complex comprises S. sugimurai and seven subspecies of S. nipponica. Electrophoretic evidence supports the separation of the two species and the subspecies classification of S. nipponica. Nei's genetic distance (D= 0.19) between S. sugimurai and S. nipponica exceeds the estimated infraspecific level. Saussurea nipponica is newly defined as a species composed of seven infraspecific taxa which have their own distribution ranges and habitats. They are in a very early stage of differentiation. The extensive morphological diversity in S. nipponica is presumed to be a result of geographical isolation under strong environmental selection.
Isozyme Diversity is Low in Paeonia californica (Paeoniaceae)
Authors: Zona Scott , Rieseberg Loren H. , Carter Ronald L. , Doan Khiem
Published: February 2005

Abstract The California Peony (Paeonia californica), a regional endemic and outcrossing species, is almost completely monomorphic for 23 isozyme loci. The level of genetic diversity in the California Peony is similar to that of narrow endemics and/or self‐fertilizing species. This paradoxical result may be explained by either of two hypotheses: 1) low initial polymorphism of the ancestral genome, or 2) population bottle neck.
Germination Ecophysiology of the Mesic Deciduous Forest Herb Polemonium reptans var. reptans (Polemoniaceae)
Authors: BASKIN JERRY M. , BASKIN CAROL C.
Published: February 2005

Abstract Seeds of Polemonium reptans var. reptans, a perennial herb of mesic deciduous forests in eastern North America, mature in late May‐early June, and a high percentage of them are dormant. Seeds afterripened (came out of dormancy) during summer when kept in a nylon bag under leaves in a nonheated greenhouse or on wet soil in a 30/15°C incubator. The optimum temperature for germination of nondormant seeds was a simulated October (20/10°C) regime. In germination phenology studies in the nonheated greenhouse, 20–30% of the seeds that eventually germinated did so in October, and the remainder germinated the following February and March. Since low (5°C) winter temperatures promote some afterripening (ca. 50%) and do not cause nondormant seeds to re‐enter dormancy, seeds that fail to germinate in autumn may germinate in spring. Thus, the taxon has very little potential to form a persistent seed bank. The large spatulate embryos and ability of seeds to afterripen at high temperatures means that seeds of P. reptans var. reptans have nondeep physiological dormancy, unlike many herbaceous woodland species, which have morphophysiological dormancy.
Clinal Variation of Frond Morphology and its Adaptive Implication in the Fern Ceratopteris thalictroides in Japan
Authors: MASUYAMA SHIGEO
Published: February 2005

Abstract Frond morphology of the highly polymorphic, annual fern Ceratopteris thalictroides was examined for local populations in south and central Japan. Among the characters examined, frond length and frond dissection were most useful for recognizing several forms. Through the comparison of these characters among populations, a geographically clinal pattern of variation was recognized; plants in higher latitudes have smaller and less dissected fronds. Plants usually grow in rice paddies during a limited period from the harvest time to the beginning of the frost season. Concordance was observed between the degree of frond length and dissection of populations and the length of the viable period in their localities. The variability of cultivated progeny of selected populations from the south and the north suggests that there are at least two ecological lines; one is genetically restricted to large and much dissected fronds and the other to smaller and less dissected fronds. The latter may be an adaptation to the short viable period in rice paddies in northern regions. High phenotypic plasticity enables these lines to adjust well the degree of frond length and dissection to the length of the viable period in each locality.
Allozyme Variation and the Genetic Structure of Populations of the Rare SedgeCarex misera(Cyperaceae)
Authors: SCHELL CHRIS M. , WATERWAY MARCIA J.
Published: February 2005

AbstractCarex miserais a rare sedge, endemic to rocky outcrops and mountain summits within the southern Appalachian Mountains from northern Georgia to northern North Carolina. We assessed allozyme diversity for 406 individuals from nine populations over most of the geographic range. Twenty‐seven putative loci were assayed and eight (30%) were found to be polymorphic. Nei's gene diversity statistics (HT=0.043,HS=0.019,GST=0.551) indicated low levels of variation but relatively highly differentiated populations, suggesting little gene flow. Significant deviations from genotypic expectations under Hardy‐Weinberg equilibrium, high positive fixation indices, and the existence of small genetic neighborhoods within populations suggest that at least some inbreeding occurs. Cluster analysis of Nei's genetic identity statistics and principal component analysis of allele frequency data showed high similarity among the six southern populations with the two northern populations more differentiated from them and from each other. These results suggest that preservation of the northern populations is necessary to conserve the already low levels of genetic diversity within the species.
Life History Studies on the Genus Trillium (Liliaceae) VI. Life History Characteristics of Three Western North American Species and Their Evolutionary‐Ecological Implications
Authors: KAWANO SHOICHI , OHARA MASASHI , UTECH FREDERICK H.
Published: February 2005

Abstract Life history characteristics of three western North American Trillium species, i. e., T. ovatum (Pedicellate‐group), T. albidum and T. petiolatum (both Sessile‐group), were critically investigated and compared. The stage‐class structure, based upon leaf area, of populations of the three species all were indicative of stable populations, even though the species occurred in contrastingly different habitat conditions. Trillium ovatum occurred in the deep shade of mesic coniferous forests on mountain ridges or slopes. Trillium albidum was found in exceedingly damp sandy‐loam soils in deciduous forests developed on the lowland flood plains. Trillium petiolatum occurred on dry rocky or gravelly shrub‐dominant areas. There was a gradual but conspicuous decrease in the number of individuals in the early juvenile stages, followed by similar numbers of plants in the intermediate stages and mature flowering stages. Recruitment of offspring appears to be exclusively dependent upon sexual reproduction in all three species, since none of the species formed vegetative offshoots as found in some sessile group species occurring in eastern as well as western North America. Analysis of spatial distributions within the populations of T. ovatum and T. petiolatum revealed successive changes from aggregated (juveniles) to random (intermediate stages), and overdis‐persed (flowering plants) distributions. The evolutionary‐ecological relationships of these three species are compared with those of 27 other Trillium species.
Bumblebee Pollinators and Pollination Ecotypes of Isodon umbrosus and I. shikokianus (Lamiaceae)
Authors: SUZUKI KAZUO
Published: February 2005

Abstract Morphological and geographical correspondence of floral variants of Isodon to their pollinating bumblebees shows that the selection pressure exerted through the glossa lengths has resulted in differentiation of three pollination ecotypes of Isodon umbrosus and I. shikokianus. The first was pollinated by long‐tongued Bombus diversus. It includes I. umbrosus var. excisinflexus and I. shikokianus var. occidentalis with long corolla tubes (>8 mm). The second type was pollinated by B. honshuensis, which has a medium‐sized proboscis, and includes I. umbrosus var. umbrosus, a part of I. umbrosus var. leucanthus, var. komaensis, and var. hakusanensis, and I. shikokianus var. shikokianus with medium length corolla tubes (6–8 mm). However, B. honshuensis was not found on I. shikokianus var. intermedius of this second type, but Bombus diversus thieved nectar from this variety. The third type was pollinated by B. beaticola, which has a short glossa, and includes I. umbrosus var. latifolius and a part of I. umbrosus var. leucanthus with short corolla tubes (<6 mm). The floral variants that belong to the same pollination ecotype were not distributed sympatrically, while different types (the first type and the second or the third type) are distributed sympatrically.
Competition between Shoots in Stands of Clonal Plants
Authors: DE KROON HANS
Published: February 2005

Abstract Data on shoot turnover, shoot size distributions and individual shoot growth in stands of clonal plants are reviewed and compared with shoot density regulation in non‐clonal plants. Shoots are the smallest units capable of independent existence in clonal as well as unitary plants and this comparison allows an investigation of the impact of integration and other factors on clonal shoot dynamics. Physiological integration, the capacity of clonal plants to exchange resources and growth substances between interconnected shoots, has long been held responsible for the ability of clonal plants to prevent shoot overproduction and for the general lack of density‐dependent mortality and self‐thinning. A review of published data leads to the conclusion that the effects of integration on shoot dynamics in clonal plants have been overestimated. Other characteristics such as the density‐dependent control of meristem activity, the synchronization of shoot growth in spring and the maximum shoot size, seem more important for the deviating behaviour of shoot populations of clonal plants.
Spatio‐temporal Processes in a Calcareous Grassland
Authors: LAW RICHARD , McLELLAN ANDREW , MAHDI ABDUL‐KHALIQ S.
Published: February 2005

Abstract The herbaceous plant communities occurring on nutrient‐poor calcareous soils of north‐western Europe are typically rich in species, with as many as 30–40 species m‐2. It is an open question as to what dynamic properties allow this diversity. We review evidence that we have collected on the spatial and temporal processes operating in a calcareous grassland community in England to address this issue. Our data indicate spatial aggregation of individuals within species consistent with the modular growth of the species concerned, but there is little evidence to suggest spatial structure generated by interactions between species, and we have been unable to separate most species tested into different niches. The development of spatial structure of the community through time is also consistent with dynamics that depend principally on the modular growth patterns of the different species. We suggest that there is a nonlinearity in the per capita rate of increase with the property that the community is no more than weakly dependent on densities of the species under natural conditions. The dynamic of the community is then driven more by forces external to the community than by density‐dependent effects within the community.
Phenotypic Variability in Life History Traits and Phenology of Field Populations of Cardamine flexuosa and C. fallax (Cruciferae) in Honshu, Japan
Authors: KUDOH HIROSHI , ISHIGURI YOSHIO , KAWANO SHOICHI
Published: February 2005

Abstract Variability in life history traits and phenology of field populations of Cardamine flexuosa and C. fallax was investigated. C. flexuosa is an annual that typically grows all year around and occurs as a weed in cultivated fields such as paddy fields, crop gardens and orchards. C. fallax is a typical winter‐green annual that mainly grows along the roadside on foothills. Differences in growth form of both species corresponded to variations in habitat conditions. Plants of paddy field populations of C. flexuosa normally possess many basal branches, while those of orchard populations of C. flexuosa typically have an erect growth form with few basal branches. C. fallax also possesses a typical erect growth form. Other life history traits (e.g., individual plant biomass and reproductive traits) of both species were highly variable both within and between populations. In C. flexuosa, seasonal differences were also found in flowering and fruiting performance. Synchronous flowering of all plants was observed in spring populations, while partial flowering occurred in summer‐autumn populations. Differences in the size class structure of plants in the autumn appeared to be caused by different cultivation schedules for crop plants in the fields. C. fallax, in contrast, possesses a rather fixed seasonal growth cycle as a typical winter‐green annual with a synchronized flowering in spring.
Disruptive Selection in Flowering Time of Wyethia amplexicaulis (Asteraceae)
Authors: SUZUKI KAZUO
Published: February 2005

Abstract Disruptive selection was observed in the flowering time of Wyethia amplexicaulis between two sites at different altitudes. Flowering time varied with elevation. Flowering occurred in late June in the lower sites and in mid July in the higher sites. In the lower sites, earlier blooming flowerheads produced more good seeds, but in the higher sites later blooming flowerheads were more successful. Successful seed production observed in this study was very low (4.0% on average) since some ovules or developing seeds are attacked by insect seed predators and others are aborted. In the early flowering plants, seed production was reduced primarily by the high predation rate, while in the late flowering plants the high abortion rate was important. In early July, the interval between the two flowering peaks, both factors had a significant effect on seed production. Causes of seed abortion are also discussed.
Modelling the Coexistence of Annual and Perennial Plants in Temporally Varying Environments*
Authors: COHEN DAN
Published: February 2005

Abstract The long‐term growth and coexistence of species with large mixed populations in varying environments were modelled for representative environments and life‐history characteristics of annual and perennial plants. The effects of the relationships between the means, variances, and covariances of seed yield, establishment, and survival, were explored by Taylor's expansion. The main findings are:

1. Individual variation in reproductive success within generations has no effect on long‐term growth, which is determined only by the mean growth rate of the individuals of the species. 2. In annual species with nonoverlapping generations and without seed banks, the species with the largest mean log of the annual growth rate Y, that is the product of the average seed yield per plant and the establishment probability per seed, will win in competition with other species, independent of the correlations between the growth rates of the different species. In this case there is a negative tradeoff between the mean and the variance. 3. In perennial species with a lottery type of equal access to vacant sites, a high annual survival probability allows stable coexistence between perennial species with independent or negatively correlated variance in their mean annual product of seed production and establishment Y. 4. The coexistence range and the likely number of coexisting perennial species increase as a function of the variance of the common species, and is decreased by the variance of the rare species. The coexistence range is decreased by the covariance between the growth rates of the species, and between the survival of the rare species and its growth rate. 5. If mortality in the community of long‐lived perennials is synchronized, the generations become nonoverlapping, and the competitive dynamics become similar to that of annuals. 6. Coexistence between annual and perennial species is promoted if the covariances between the annual survival and the relative yield of perennials, and between the yields of perennials and annuals, decrease and become more negative. 7. Selection for seed yield and establishment in different conditions in annuals favours a generalist strategy with low variance between years which provides a moderate yield and establishment over a wide range of environmental conditions. In perennial plants, long‐term growth rate is determined by the lifetime seed yield and establishment. Because of strong competition with annuals in the more common conditions, selection in perennials favours instead a specialist strategy, with a high seed yield and establishment at relatively rare occasions in space and time, in which there is only weak competition with annuals. 8. Coexistence of annual species with a long‐lived seed bank in the soil is also made possible by independent variation in different years of the germination, seed yield and establishment of different species, analogous to the situation of perennial plants.
Pollination Biology of Hosta sieboldiana (Lodd.) Engler and H. sieboldii (Paxton) J. Ingram (Liliaceae)
Authors: TAKAHASHI HIROSHI , GOTO YAYOI , KANEMATSU SHINKO , NIWA SHIZUKO , MORI KAZUYO , NOZAKI KUNIYOSHI
Published: February 2005

Abstract The pollination biology of Hosta sieboldiana and H. sieboldii is investigated comparatively in Central Japan. Both species have homogamous, one‐day flowers pollinated by bumblebees. The abdomens of the bees touch the stigma on the extended style when they land on the anthers inside the herkogamous flower, and autogamy is effectively prevented. However, the flowers are fairly self‐compatible, and geitonogamy may occur rather frequently because two or more flowers on a scape very often bloom at the same time and many ramets are contiguous. The pollen/ovule ratios suggest that these species are facultative outbreeders. The flower of H. sieboldii seems completely suited to bumblebee pollination. In H. sieboldiana the stigma of the flower, whose style strongly protrudes, is not always touched by bumblebees, but frequent visitation of bumblebees results in pollination of almost all the flowers. Both species have similar pollination systems but seem reproductively isolated by blooming times and habitats. Their common pollinators, however, may sometimes cause introgressive hybridization in contiguous populations.
Germination Response Patterns during Dormancy Loss in Achenes of Six Perennial Asteraceae from Texas, USA
Authors: BASKIN CAROL C. , BASKIN JERRY M. , VAN AUKEN O.W.
Published: February 2005

Abstract When subjected to simulated habitat temperatures, achenes of six perennial Asteraceae from southcentral Texas came out of dormancy during summer. In the early stages of dormancy loss, achenes of Erigeron modestus, Gaillardia suavis and Hymenoxys scaposa germinated (to ≥ 10%) in light at 12/12 hr daily thermoperiods of 15/6, 20/10 and 25/15°C and those of Pinaropappus roseus at 15/6 and 20/10°C. After additional dormancy loss, achenes of these four species also germinated at 30/15 and 35/20°C. Achenes of these four species had a Type 1 germination response pattern, which heretofore has not been reported in perennial Asteraceae. Achenes of Chaptalia nutans first germinated (to ≥ 10%) at 20/10 and 25/15°C and those of Hymenopappus scabiosaeus at 20/10°C, but with further loss of dormancy achenes of both species also germinated at 15/6, 30/15 and 35/20°C. Thus, achenes of these two species had a Type 3 pattern. This is the first report of perennials in any family with a Type 3 response pattern whose seeds come out of dormancy during summer. Presence of annual and perennial Asteraceae with Type 2 in temperate eastern North America and annual and perennial Asteraceae with Type 1 in southcentral Texas causes us to conclude that climate is more important than the type of life cycle in determining the type of germination response pattern.
Low Levels of Genetic Diversity within Populations of Hosta clausa (Liliaceae)
Authors: CHUNG MYONG GI
Published: February 2005

Abstract Genetic diversity of Korean populations in Hosta clausa was investigated using starch gel electrophoresis. Hosta clausa is widespread, grows only along streamsides, and has both sexual and asexual reproduction. Populations of the species are small and isolated. Thirty‐two percent of the loci examined were polymorphic, and mean genetic diversity within populations (Hep=0.082) was lower than mean estimates for species with very similar life history characteristics (0.131), particularly for its congener H. yingeri (0.250). The mean number of multilocus genotypes per population was 8.7, and genotypic diversity index (DG) was 0.84. Significant differences in allele frequencies among populations were found in all seven polymorphic loci (P < 0.001). About one‐fifth of the total allozyme variation was among populations (GST=0.192). Indirect estimate of the number of migrants per generation (Nm=0.48, calculated from mean GST) and nine private alleles found indicate that gene movement among populations was low. The low levels of genetic diversity within populations and the relatively high levels of genetic diversity among populations suggest that strong moist habitat preferences, clonal reproduction, low level of gene flow among populations, genetic drift, and historical events may have played roles in the genetic structuring of the species.
Pollination Biology of Oenothera (Onagraceae). The Interplay between Floral UV‐Absorbancy Patterns and Floral Volatiles as Signals to Nocturnal Insects
Authors: KAWAANO SHOICHI , ODAKI MEGUMI , YAMAOKA RYOHEI , ODA‐TANABE MINORI , TAKEUCHI MASATOSHI , KAWANO NOBUHIRO
Published: February 2005

Abstract Floral volatiles of two introduced Oenothera species, Oe. glazioviana (= Oe. erythrosepala) and Oe. biennis, were chemically examined using the headspace method. As a result, linalool, one of the monoterpenes, was found to be the main constitutent of floral volatiles, with several other undetermined substances. Visual signals of these two Oenothera species were the same, with a strong UV‐absorbent spot in the center of the corollas. Large nocturnal hawkmoth species such as Theretra japonica, Agrius convolvuli, and Deilephila elphenor lewisil are major pollinators for these two Oenothera species. An interplay between floral UV‐absorbancy patterns as visual signals and floral volatiles released seems to be playing a significant role in pollinator attraction. Nectar utilization and the breeding system of Oe. glazioviana were also examined.
Juvenile Demography of Copaifera pubiflora Benth. (Leguminosae, Caesalpinioideae) near Parent Tree
Authors: RAMIREZ NELSON , HOKCHE OMAIRA
Published: February 2005

Abstract The age structure and distribution of seeds, seedlings, and non‐reproductive (juveniles) plants of Copaifera pubiflora relative to the distance from parent trees were studied in the Venezuelan central plains. Age structure differentiated between years when comparisons were made for plants in one‐year interval classes. This difference was associated with the proportion of plants less than one year old and those eight years old. Age structure did not differ between years when comparisons were made for five‐year age intervals. The age‐specific death rate (qx) of non‐reproductive plants grouped in five‐year intervals showed a zig‐zag pattern until 30 years of age. The age‐specific death rate in the first five years was lower in 1977 than in 1982. The finite rate of increase of juvenile plants was 1.06, and the average figures of age, biomass, height and density of plants per plot did not differ between 1977 and 1982. These parameters indicated a demographic equilibrium and the absence of an age‐plant hierarchy. The number of seeds and juvenile plants decreased with distance from parent trees. The correlation between plant and seed densities was significant. Multivariate canonical analysis indicated that the age, height and number of leaves of individual plants tended to increase with distance from the parent tree. A second canonical correlation, between density and distance, and the traits of plants by plot indicated that the maximum age and biomass per plot increased simultaneously with the density. These results exhibited a dichotomy between individual plants and the plant per plot behavior. Plant survival rate tends to increase with distance from the parent trees, but plants at high densities near the parent are never more than 30 years old.
Spatial Genetic Structure among Korean Populations ofCamellia japonicaandEurya japonica(Theaceae)
Authors: OH GAP SOO , KIM JUNG HEE , KANG SOON SUK , YEEH YEEHN , CHUNG MYONG GI
Published: February 2005

AbstractCamellia japonicaandEurya japonica, broad‐leaved evergreen woody plants, are widely distributed in eastern Asia.Eurya japonicais dioecious, whereas flowers ofC. japonicaare perfect. We investigated the spatial distribution of genotypes among 15 and 21 Korean populations ofC. japonicaandE. japonicausing spatial autocorrelation analysis of enzyme polymorphisms to test the previous prediction that dioecy is a primary factor which increases interpopulational gene flow. The patterns of spatial genetic distribution among populations of both species are very similar: percentage of significant Moran's /values (15 vs. 17 forC. japonicaandE. japonica) and percentage of significant overall correlogram (18 vs. 20 forC. japonicaandE. japonica). For both species, the patterns of average Moran's/values for each distance class were very similar as in an isolation by distance model. It may be concluded that dioecy may not a primary factor in shaping spatial genetic structure inE. japonica.Instead, abundant and continuously distributed patterns observed inE. japonicaand an occasional pollen transfer by birds between isolated island populations ofC. japonicain Korea may play roles in shaping spatial genetic structure among Korean populations of the two species.
Population Genetic Aspects of Gametophytic Self incompatibility
Authors: CLARK ANDREW G.
Published: February 2005

Abstract In gametophytic self‐incompatibility, the S‐locus encodes an S‐protein whose expression results in successful pollination only when the pollen allele differs from both maternal alleles. Analysis of nucleotide and amino acid sequences of a number of S‐alleles has revealed extraordinary allelic sequence divergence and an excess of interspecific shared polymorphism. Population genetic theory and analysis of the distribution of the number of shared polymorphic sites verifies that the sequence diversity is consistent with the alleles being extraordinarily old. Theory also predicts that S‐alleles will exhibit less population structuring in a subdivided population than will a neutral locus, and data are being collected to test this. Self‐incompatibility must involve two features ‐ a pollen component that specifies the identity of the pollen and a pistil component that recognizes and elicits a response to self‐pollen. The S‐locus clearly determines the pistil component, but lack of expression of S in pollen leaves open the possibility that there may be another pollen factor. Experiments with transgenic plants have demonstrated that the S‐protein expression in the pistil is necessary and sufficient to determine the pistil phenotype. However, several lines of evidence suggest that the degree of elimination of self‐pollen in plants with gametophytic self‐incompatibility depends on additional genetic factors besides the S‐locus. Modifiers may affect self‐incompatibility by affecting either the pollen component, the pistil component or both. Population genetic models that test the consequences of modification of these two components are reviewed and extended. Conditions for invasion of reduced degree of self‐incompatibility depend in part on the level of inbreeding depression.
Phenotypic Plasticity in Growth Habit in Plantago lanceolata: How Tight is a Suite of Correlated Characters?
Authors: VAN TIENDEREN PETER H. , VAN HINSBERG ARJEN
Published: February 2005

Abstract The growth habit of the rosette plant Plantago lanceolata is highly variable, and many vegetative and reproductive traits co‐vary. At one end of the range plants have relatively few but long and erect leaves, form few daughter rosettes, and produce a limited number of large spikes, with relatively heavy seeds. Plants at the other end of the range have the opposite characteristics. This suite of characters was shown to correlate with the height of the vegetation in mid‐summer. The causes for this association between different traits were investigated in different experiments, with the following results:

Plants from two contrasting habitats both react strongly to light intensity and the red to far‐red (R/FR) ratio of the ambient light. Light intensity mainly affected plant size, whereas light quality affected the growth habit. Populations differ in their mean response rather than in the level of plasticity (i.e., slope of the reaction norms). Experiments show that genetic factors (population effects), R/FR ratio, and hormone treatments (GA or CCC) have similar effects on morphology, and are largely additive and interchangeable.

Ten different populations were grown in a common garden, so that the genetic (clonal) correlation within populations, and their bivariate phenotypic means could be compared. Trait combinations which deviated in the same direction (both higher of both lower than the mean over all populations) on average had positive clonal correlations within populations, whereas combinations which deviated in opposite directions had negative correlations.

Artificial selection on leaf length, performed under a high or a low R/FR ratio showed clear responses to selection, with heritabilities around 0.4. Correlated responses were found in many other traits, and genetic correlations were similar to the trait associations for the means of different natural populations. Correlated responses to selection depended on environmental circumstances. Under a high R/FR ratio (sun) evidence for a size/number trade‐off was found for leaf length and leaf number. Under a low R/FR ratio, however, a trade‐off between leaf length and leaf quality was found.

In conclusion, the trait associations that are so characteristic for the growth habit in Plantago lanceolata are probably due to differences in hormone levels or activities. Genes and environmental factors affect growth habit in similar ways, by tapping into this regulatory mechanism. In the field, selection can lead to concerted changes in the mean of different traits, but changes in plasticity will be slow.
Characteristics of Nectar Secretion by Lycium cestroides, L. ciliatum (Solanaceae), and Their Hybrid
Authors: GALETTO LEONARDO , BERNARDELLO GABRIEL
Published: February 2005

Abstract Nectar sugar composition, nectar secretion patterns, and effects of removal are compared in a natural hybrid experimentally supported (Lycium ciliatum × cestroides) and its parental species (L. ciliatum and L. cestroides). The nectar of L. ciliatum and L. ciliatum×cestroides is hexose dominant, but each taxon shows a distinctive pattern: more glucose than fructose in the former and the opposite pattern in the latter. L. cestroides has sucrose‐rich nectar with more fructose than glucose. Both parental species show a similar sugar production pattern: the sugar content declines at the end of the flower lifetime due to nectar reabsorption. In contrast, in the hybrid, nectar secretion is continuous and there is no nectar reabsorption. Data obtained among the taxa are correlated with corolla depth: the deeper the corolla tube, the more diluted and the higher the volume of the nectar. Nectar production after removal is increased in L. cestroides whereas it is not affected in the hybrid or in L. ciliatum. Chemical composition and response to removal relate the hybrid to the maternal parent (L. ciliatum).
The Floral Biology of Duchesnea (Rosaceae)
Authors: NARUHASHI NAOHIRO , SUGIMOTO MAMORU
Published: February 2005

Abstract Pollinators and UV photos of flowers of Duchesnea chrysantha and D. indica are discussed. The petals of D. chrysantha reflect UV light strongly, while those of D. indica have a nectar guide appearing as a spot at the base of the petals that absorbs UV light. This is the same as in Potentilla which is closely related taxonomically. In Duchesnea, we consider the presence of a nectar guide to be a derived character. The petals of D. chrysantha and D. indica are distinguished by the presence or absence of nectar guides, but both species are pollinated mostly by the same kind of pollinators, which are commonly small polylectic insects. The main pollinators are four small bees (Andrena knuthi, A. minutula, Halictus aerarius, Lasioglossum sp.) and three syrphid flies (Paragus haemorrhous, Sphaerophoria macrogaster, S. philanthus). The total number of insect visitors in D. chrysantha was 60 species, while in D. indica there were 51. There was no significant difference in the visitors to the two Duchesnea species, therefore, the adaptive meaning of the presence of nectar guides was not determined in Duchesnea.
Progenesis as an Adaptive Strategy in the Annual Fern Ceratopteris thalictroides in Japan
Authors: MASUYAMA SHIGEO
Published: February 2005

Abstract To see the regional variation of Japanese Ceratopteris thalictroides in the mode of vegetative growth of sporophytes, offspring sporophytes of 12 local populations were cultivated under long day, short day, and low temperature conditions. In contrast to sporophytes of southern populations, those of northern populations exhibited a strong tendency to form fertile leaves with a short period of vegetative growth. From morphological analyses of sterile leaves, four patterns were recognized in the shortening of the vegetative‐growth period: one is shortening by a variation ofacceleration, a type of heterochrony, and the remaining three are shortening by progenesis, another type of heterochrony, linked to the long day, the short day, or low temperature. Since the period during which sporophytes of C. thalictroides can grow is shorter in higher latitudes in Japan, heterochrony, especially progenesis, in northern populations is regarded as an adaptive strategy of this species to expand its distribution towards the north.
Comparative Studies of the Hanabusaya asiatica and its Allied Groups by RAPD Analysis
Authors: YOO KI OUG , LEE WOO TCHUL , KIM NAM SOO , LIM HAK TAE
Published: February 2005

Abstract The phylogenetic relationships between Hanabusaya asiatica and its allied groups were assessed by Randomly Amplified Polymorphic DNA (RAPD) analysis of genomic DNA, and their taxonomic status was reevaluated at the molecular level. The analyzed plants consisted of 36 populations of eight genera and 27 taxa. Forty‐two out of 101 primers(10‐mer) screened were able to amplify DNA. Only 19 primers, however, actually succeeded in DNA amplification, resulting in 523 randomly amplified DNA fragments. The analyzed taxa showed very high polymorphism, allowing each individual taxon to be identified based on RAPD analysis. All eight genuses were differentiated from each other at the 0.86 level of similarity index value. In particular, Hanabusaya asiatica was distinguished from its closely related genus. Intraspecific and interspecific relationships were quite close, at levels ranging from 0.77 to 0.99. Our RAPD analysis supports the previous data based on morphological and palynological studies.
Floral Ecology, Carinal‐Lobe Release, Pollination and Reproductive Success in the Wild and Domesticated Forms of Hyptis suaveolens (L.) Poit. (Lamiaceae) in Mexico
Authors: ALURI JACOB SOLOMON RAJU , VERGARA‐SANTANA MARTHA I. , JUAREZ SEBASTIAN LEMUS
Published: February 2005

Abstract Hyptis suaveolens is a weedy species growing wild in the tropics. In Mexico, additionally, it has two non‐weedy domesticated forms. The wild form is designated as violeta and the domesticated ones as blanca‐violeta and blanca, based on stem, flower and seed characters. The wild form has flowers with violent carinal explosion, while the domesticated forms have flowers with non‐violent carinal explosion. The carinal structure is formed by the median lobe of the lower corolla lip which conceals the stamens and the stigma even after the unfolding of the other lobes of the corolla. The carinal lobe explodes when the flower visitor lands on the flower. All three forms are foraged indiscriminately by the same species of bees. Flies and a wasp also forage on these flowers, but their role in pollination is negligible. The foraging behaviour of bees suggests that selfing is promoted during forenoon hours and outcrossing during afternoon hours. There is a direct relation between flower density, bee frequency and reproductive success. Bees approach the flowers from the front probe in an upright position; and they effect carinal‐tripping and sternotriby while probing for either pollen, nectar, or both. Apis and Exomalopsis probe the flowers also from above the upper corolla lip in which case pollination is not ordinarily effected. All three forms are both self‐ and cross‐pollinating. The domesticated forms have higher fecundity than the wild. The wild form reseeds itself, while the domesticated ones cannot, as their larger fruiting calyx requires seed‐dispersal agents. H. suaveolens, particularly its domesticated forms, can be best exploited as a potential new crop.