摘要:

AbstractPlasticity in growth, reproductive energy allocation (RA), and reproductive output were investigated inHelianthus annuusL. cultivar.Russia(Compositae) grown under varying densities and soil nitrogen levels. The role and behaviour of pollinators in seed production was also examined.Exceedingly marked plastic responses were detected in individual biomass, the patterns of resource allocation to total reproductive structures (RA) and also to propagules, fecundity, reproductive outputs, and propagule size and weight under changing densities and soil nitrogen levels. Plants cultivated at higher densities exhibited proportionately lower individual biomass, lower RA, lower fecundity, lower seed output, and smaller seed size in response to increasing density and decreasing soil nitrogen levels. However, differences due to different N‐levels were not as great as those to changing density.One of the most significant findings was that seed production under limited resource availability, i.e., lack of ample solar radiation and soil nutrients, due to strong interference at higher density plots, is exceedinglycostlty, This was most clearly demonstrated by a very sharp increase in relative energy partitioning to a single propagule in response to the increased density and decreasing nitrogen levels, the relative energy cost to a single achcne (RA) increasing from one to twenty‐fourfold. Reproduction was also affected by pollinator‐limitations, and seed size showed a marked position e

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00010.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThree different types were found in the floating pattern ofKandelia candel(L.) Druce propagules: horizontal‐floating type, vertical‐floating type and sinking type. These correspond to the specific gravity, which increases with flooding in sea water and the repeated exposure to air. The floating types gradually change to the sinking type. In nature, such a condition is found only under the intertidal zone of shallow lagoons where floating propagules can increase their specific gravity, lie on the mud deposits and develop their roots in contact with the muddy soil. The J‐shaped seedlings frequently found in K. canel populations in mangrove swamps might be recognized as evidence of growing up in the intertidal zone.It is speculated that the horizontal‐floating propagule has a role as a drifter in the ocean and long‐distance disperser, the vertical‐floating one as a colonizer of nearby populations and the sinking one as a successor in the origi

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00011.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractPeroxidase phenotypes of two all‐agamospermous “species” ofEupatoriumin the southeastern United States were examined. The result supported a hybrid origin (E. recurvans × E. rotundifolium) forE. scabidumand an autopolyploid origin fromE. recurvansforE. mohrii.Notable variations ofE. scabridumin its leaf morphology and peroxidase phenotype were suggestive of occasional sexuality in this agamospermous “

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00012.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractFour JapaneseTrillium(Liliaceae) species which are representative perennial herbs of the temperate deciduous forests—Trillium kamtschaticum(2x),T. apetalon(4x),T. tschonoskii(4x) andT. smallii(6x)—were studied for their reproductive characteristics, e.g., patterns of reproductive resource allocation and reproductive output.In spite of the differences in ploidy levels (from 2x to 6x), all four species showed very similar reproductive traits. It became evident that in response to the increase in reproductive allocation to total reproductive organs (RA), the number of seeds produced per plant (PN) clearly increased. This trend is well in accord with the relationship found in four North American species and also several temperate woodland perennial herbs which occur in closed, stable and predictable environments, and possess typical xenogamous breeding systems. Although there is no conspicuous trend between ploidy levels and PN, one of the significant differences noted in this study was in seed weight, which ranged from 2.93 mg in diploids, to 3.42–3.45 mg in tetraploids, and to 4.47 mg in hexap

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00013.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe stage class structures and the reproductive characteristics as well as energy allocation to reproductive activities were studied in four North AmericanTrilliumspecies (Liliaceae)—T. grandiflorum, T. erectum, T. undulatum and T. sessile.In addition, a comparison was also made of the life history characteristics of these four North American species with those of Japanese species.As a result, the stage class structures of these four species were discriminated for each species based on leaf area. The study revealed that they all possess similar depletion curves characterized by a conspicuous decrease of individuals belonging to the juvenile stages (from stage class 0 to 2). The switchover of stages, i.e, from one‐leaf to three‐leaved sterile stages, from three‐leaved sterile to fertile stages, orvice versa, was found to occur in different size ranges for each species. In all four species examined, reproductive allocation to total reproductive structures (RA) at the mature fruiting stage was almost independent of biomass, but the number of propagules produced per plant (Pn) was clearly dependent on the size of plants (individual biomass). Three species,T. grandiflorum, T. erertumandT. sessile, showed a proportional increase in Pnin response to the increase in RA, as found in four JapaneseTrilliumspecies, and also in a number of other perennial herbs growing in closed, stable and predictable environments with an outbreeding system. This trend, however, was not obvious inT. undulatum, i.e., Pnwas independent of RA. With respect to seed characteristics, these species exhibited relatively high seed setting rates per ovule.Trillium undulatumshowed very high fecundity, 92.40% and 85.38% in two years' samples, suggesting that this species is a typical inbreeder. Contrary to JapaneseTrilliumspecies, which showed proportional increase in seed weight in response to an increase in ploidy levels (from 2xto 6x), these diploid species showed wide variation in seed weight, ranging from 4.15 mg to

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00014.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractA total of 22 population samples of three endemic species ofCallicarpain the Bonin Islands (the Chichijima Islands and the Hahajima Islands) were examined for nine leaf characters to clarify the present status of morphological variations. Results showed that three species are distinetly recognizable and have their own patterns of variation.Callicarpa glabraandC. nishimuraewere relatively less variable and adapted to limited habitats only in the Chichijima Islands. Thus these species were regarded as specialized species.C. subpubescenswas more variable than the above two species and distributed widely in both of the two island groups. This species was morphologically differentiated between the two island groups. In the Hahajima Islands where two other species were not distributed, several plants ofC. subpubsecenswere similar toC. glabra.The populations ofC. subpubescensin the Hahajima Islands were inter‐populationally more variable than those in the Chichijima Islands.C. subpubescensoccupied various habitats within the Bonin Islands and was regarded as a diversified specie

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00015.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractLilium lancifoliumThunb, is the only polyploid species complex consisting of 2x (2n=24) and 3x (2n=36) forms in the genus, both of which are highly self‐sterile. They are cytologically differentiated into various nucleolar types by number and combination of four kinds of nucleolar chromosomes. The 3x form is widespread from the North‐East district of China to the Japanese Islands through the Korean Peninsula. However, the 2x form is localized and grows singly or together with the 3x form in the narrow zone from southern Korea to the Tsushima Islands, Japan. The 2x form reproduces by sexual as well as by asexual means, but a sterile 3x form has asexually persisted to the present. Generally speaking, the 3x form is the allotriploid which has originated from hybridization between a 2x form and a closely related species such asL. maximowicziiin the remote past. In the present study, another possibility for the presence of the autotriploid form is newly proposed based on its karyotype and geographic distribut

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00016.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe taxonomic relationships of 53 species (122 strains) in subtribeBrassicinaewere studied by using Euclidian distances calculated from 53 metric characters. Through cluster analysis applied to the species and subspecies in the genusBrassica, six large clusters could be defined. By the same method,Diplotaxiswas grouped into four clusters,Erucastruminto two, andSinapisinto two. These clusters coincided in general with the taxonomic sections of Schulz (1936), but some exceptions were noted. Most of the exceptional species were those placed in critical positions by cytogenetical observations. It was found that cluster grouping reflected the cytogenetical relations of species fairly well.Relationships among clusters and genera are represented by a Euclidian distance matrix, and the evolutionary trends of those taxa are discussed. Clusters B‐3(in Brassica), D‐1 (in Diplotaxis) and E‐1 (inErucastrum) are closely related to each other, forming a complex. This complex is closely related toSinapidendron.It is postulated that this complex andSinapidendronmight have retained some characters in common with their putative ancestor. Species in the other clusters are considered to be derived from that hypothetical ancestor in the course of evolutionary diver

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00017.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe pollination and breeding systems ofCampanula punctataboth in the Izu Islands and the mainland (Honshu) adjacent to the islands were investigated. The predominant pollinators of campanulas are: 1)Bombus diversusin Honshu, 2)Bombus ardensand halictid bees on Oshima Island, and 3) halictid bees on the islands of Niijima, Kodzushma, and Hachijo. The absence of bumble bees exceptB. ardenson Oshima Island, and the abundance of halictid bees represent a kind of island effect. Flowers of the campanula in the Islands were found to be smaller than those of the mainland. This might have resulted from adaptation to the small pollinators. Pollination experiments with plants grown from seeds revealed the following differences in breeding system: 1) most of the campanulas from Honshu were highly self‐incompatible (SI) and a few partially self‐compatible (SC), 2) one half of the plants from Oshima Island were more or less SC and the remaining highly SI, 3) those from Hachijo Island were SC and potentially autogamous. The breakdown of dichogamy co‐operated with self‐compatibility in the development of self‐fertilizing ability in Hachijo plants. Several possible causes for the change in the breeding system including the change in pollinators in the Islands are

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00018.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe evolutionary history ofEupatoriumis interpreted on the basis of the cytogeo graphical data from polyploid complexes. In North America, agamospermous polyploid complexes have their centers of distribution in the southeastern United States, Polyploids have a greater geographical range and occur more abundantly than their corresponding diploids. The diploids, which are related to polyploids, are confined either along the Coastal Plain, or in the Ouachita, Ozark and Appalachian Mountains, which are regarded as their refuges during the last lee Age. Speciation in Asian eupatoria has been induced predominantly by geographical isolation at the diploid level in the islands along the continental are. The polyploids of Asian taxa are confined to the rather limited habitats created by recent human activities. Both North American and Japanese eupatoria appear to have diminished their distribution to the southern refuges at some stage during the last Ice Age and since have spread northwards as the climate has improved. During this period, the range extension has been accelerated by human activities, and the agamospermous polyploids have colonized preferentially into the newly available, drier and more open habitats than those which diploids inhabited previously. This range extension has permitted many secondary contacts between previously separated species and has given rise to the new polyploid hybrids. The moist inhabiting species have stayed strictly or largely on the diploid level throughout their widespread geographical range up to the present time.

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00019.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY