摘要:

AbstractPolygonella macrophyllaSmall is a rare, perennial, primarily gynodioecious plant species endemic to a narrow zone of coastal sand pine scrub habitat along the Gulf of Mexico from Carrabelle, Florida, to Gulf Shores, Alabama (U.S.A.). The species is comprised of a crimson‐red flowered form (“rubra”), known from only two populations at the eastern distributional limit of the species, and a white/pink flowered form ("alba") represented by several populations throughout the remainder of the range of the species. An electrophoretic investigation revealed that commonly used measures of gene diversity are very close to expected values in “rubra” given the combination of ecological attributes displayed by the species; however, gene diversity in “alba” is much lower than expected. Population differentiation is high, with estimates of the coefficient of gene differentiation (GST) indicating that more than 30% of the diversity is among populations. Lack of gene flow among populations, estimated to be at most 0.6 migrating individuals per generation for the species, is a likely cause of greater population differentiation. High inbreeding, detected both within populations and within the species, is suggestive of high rates of self‐fertilization in hermaphroditic plants and/or biparental inbreeding in sm

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1991.tb00204.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractTheSaussurea nipponicacomplex was examined with enzyme electrophoresis. Earlier morphological evidence suggested that the complex comprisesS. sugimuraiand seven subspecies ofS. nipponica. Electrophoretic evidence supports the separation of the two species and the subspecies classification ofS. nipponica. Nei's genetic distance (D= 0.19) betweenS. sugimuraiandS. nipponicaexceeds the estimated infraspecific level.Saussurea nipponicais 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 inS. nipponicais presumed to be a result of geographical isolation under strong environmental selection.

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1991.tb00205.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractBreeding‐system data have been available for a large number and diverse array of angio‐sperms for a relatively long time. In contrast, breeding systems of ferns and their allies (pteridophytes) have only recently been examined, and breeding‐system data from natural populations of sporophytes are still lacking for pteridophytes representing many life‐history strategies. Few studies, for example, have examined breeding systems of tropical pteridophytes, and no breeding‐system data are available for tree ferns. We therefore examined the breeding systems of three species of tree ferns from Costa Rica,Alsophila firma(Cyatheaceae),Cyathea stipularis(Cyatheaceae), andLophosoria quadripinnata(Lophosoriaceae) using enzyme electro‐phoresis. Genetic data were used to estimate intragametophytic self‐fertilization andF, the fixation index. Analysis of genetic data indicates that the gametophytes of these three species predominantly cross‐fertilize; all three species would be characterized as outcrossers. However, some population‐to‐population variation in breeding system was detected in all three species. Outcrossing also typifies a diverse array of temperate ferns. Thus, despite the potential for self‐fertilization, outcrossing appears to characterize the majority of pteridophytes representing a variety of evolutionary lineages, life‐history strat

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1991.tb00206.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractIntra‐population variations of several characteristics related to fertility were assessed for a nature‐reserve population ofPrimula sieboldiiin the flood plain of the Arakawa River. Although there were large intra‐ and inter‐clonal variations of fruit and seed sets as well as other female fertility components in the 13 clones examined, female fertility was generally low, except in a homomorph clone. Pollinator availability was assessed by continuous monitoring of insect visits with 8 mm film. No insect visits were recorded during the monitoring of total 68 flowers over 16 hours in the nature‐reserve population. In contrast, a high pollinator visitation rate was recorded in a reference population ofP. sieboldiion the flank of Mt. Yatugatake. Thus, the low rates of seed production in the nature reserve was due to a shortage of compatible pollens as a result of the limitation of pollinator availability. Stigmas of flowers in various clones occasionally were loaded with pollen grains whose sizes were not significantly different from those of anther pollens of the same flowers. However, pollen germination on stigmas was observed only in the flowers of a homo‐morph clone whose flowers have pin‐type stigmas and anthers with compatible thrum‐type pollens at the same height. Exceptionally high fertility of the homo‐morph clone would be associated with its

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1991.tb00207.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractFruit and seed set in a dioecious tree,Phellodendron amurensevar.sachalinensegrown in isolation, were studied for three years in Hokkaido, northern Japan. Hand pollination did not affect fruit set during the three years, but did affect seed‐set by increasing the proportion of fruits with higher seed numbers. Artificial defoliation resulted in decreased mean seed mass, but caused no significant differences in mean seed number per fruit. Total seed mass per infructescence increased with inflorescence size except with artificial defoliation where it reached an upper limit. Although the results of the artificial defoliation treatment indicate that resources are most important for fruit and seed set, it is concluded that fruit and seed set of the tree are not limited by resources, since the number of fruits increased with inflorescence size and an artificial defoliation treatment did not decrease seed‐num

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1991.tb00208.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractSignificant differentiation in relative growth rate (RGR) was found among three ecologically contrasting populations ofAgrostis stolonifera.Under low nitrogen conditions the sand dune population had the highest mean RGR. The plastic response in RGR to different levels of nitrogen supply was significantly higher in the inland meadow population than in the polder and sand dune populations. The (colonizing) polder population tended to have the highest variation for RGR. Variation in RGR within populations was mainly environmentally determined, although in the polder population significant effects of genotype and of genotype × nitrogen level were found. The repeatability for RGR in this population proved to be different from zero under both nitrogen conditions. Root/shoot ratios of the three populations were not different from each other, independent of the level of nitrogen supply. Correlations between RGR and survival of genotypes within the populations were not significant, which points at the influence of genotype × environment interactions or the possibility that genotypic differences in RGR do not necessarily indicate an adaptation to any habitat, not even the home sit

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1991.tb00209.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe hostas native to Korea have never been carefully reviewed taxonomically and their patterns of variability are not well understood. For morphological and electrophoretic studies, samples of rootstocks were taken from 45 KoreanHostapopulations and from two populations ofH. tsushimensisN. Fujita on Tsushima Island, Japan. For morphometric analysis, ten plants from each of twenty populations were grown and observed under greenhouse conditions. Fifty‐one floral and vegetative characters were examined on each plant and the data were analyzed using principal components and cluster analysis. Six Korean species can be recognized:H. yingeriS. B. Jones (Taehuksan, Sohuksan, and Hong islands);H. capitata(Koidz.) Nakai (southern Korea);H. clausaNakai (central and northern Korea);H. minor(Baker) Nakai (southeastern Korea including Wan and Kojae islands);H. venustaF. Maekawa (Cheju Island); andH. jonesiiM. Chung (southern islands). Morphological features contributing to recognition of the natural groups were: ridges on the scape; the width of inner and outer floral lobes; bracts pappillous at apex; length and color of the bracts; length of inflorescences; the withering condition of the bracts; scabrous nerves on the lower leaf surface; and size of the leaves. Isozyme analyses indicate a recent origin ofH. venustafromH. minor.Although hostas are easily hybridized, natural hybridization seems to be rare in Korea. The morphological and isozyme studies identified no hybrids and the species are well characterized by their distribution patterns, phenology, and habitat

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1991.tb00210.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1991.tb00211.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY