摘要:

AbstractAn evolutionary approach to reproductive allocation is extended to the realm of size‐specific demography. Questions of how resource is allocated between male and female functions and between present and future reproduction are investigated. The concepts of reproductive value and the Euler‐Lotka equation are extended to cover size‐specific demography. The criterion of life history evolution in age‐specific demography is also extended and applied to the prediction of the reproductive allocation pattern selected for in accordance with the characteristics of a plant species. The theory is applied to the problem of sex change. Our predictions are: (1) Sex allocation pattern will change according to the size of the plant if the increase in reproductive success, growth or survival rate with increasing size is different between sexes. (2) Sex change (from one sex to the other) is selected for if the plant has a concave tradeoff relationship between male and female reproductive success in each reproductive season. Gradual sex change (relative increase of resource allocation to one sex as the plant increases in size) is selected for if the plant has a convex trade‐off relationship. Also by this extension of reproductive allocation theory to size‐specific demography, testability of the theory with field data is greatly increased because it enables us to examine the plants in which size rather than age is a better predictor of demographic

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1987.tb00029.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractA projection matrix model was adopted to describe the population dynamics ofArisaema serratum(Thunb.) Schott. This method is most appropriate for describing a complex life history, such as size‐specific determination of sex expression inArisaema. Size classification was determined from both the life history stage and the pseudostem diameter at ground level, which was transformed into natural logarithms.The calculated population growth rate based on averaged data from 1981 to 1986 was very close to unity. The survival rate was lowest at the seedling stage and gradually increased for larger size classes. But the survival rate was almost the same for the male stage and female stage irrespective of size classes.Individuals in small size classes made greater contributions to the population growth rate (λ) if they were in the asexual stage than in male or female stages. Those individuals in intermediate size classes had greater effects on λ if they were in the male phase and those in large size classes had greater effects on λ if they were in the female s

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1987.tb00030.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractThe growth, reproductive characteristics and energy allocation to reproductive activities were studied in a Japanese species of jack‐in‐the‐pulpit,Arisaema urashimaHara (Araceae). The stage class structures of this species were based on leaflet numbers and leaf area of individual plants in four different populations in Wakayama Prefecture, Honshu, Japan.Populations ofA. urashimapossess unique male‐biased population structures, with sex ratios (male/female) of 3.14 to 5.00. In this typical sequential hermaphrodite, functionally dioecious species, the switchover from sterile to the male stage orvice versawas found to occur usually in the 11–12 leaflet class, and from a male to female stage orvice versain the 13–14 leaflet class. However, a large proportion of juvenile plants belonging to the 3–4 to 9–10 leaflet classes, which attained 92.3–98.9% in all four populations, may possibly be recruited by a most vigorous cormlet propagation which occurs every season. Seasonal changes in population structure were also examined for five years, from 1981 to 1985, but population structures remained more or less in the same state, although the sex ratios changed from 3.14 to 6.85.Reproductive allocation (RA) was examined at both the flowering and fruiting stages. The RA to total reproductive structures at the flowering stage showed very conspicuous negative correlations to total biomass for both male (r= ‐0.676, P<0.001) and female plants (r= ‐0.861, P<0.001), whereas the RA at the mature fruiting stage was almost independent of individual biomass. The number of propagules produced per plant (PN) was weakly correlated with the individual biomass (r=0.346, P<0.05). The PNper plant exhibited a conspicuously proportional increase in response to the increase in RA (r=0.860, P<0.001). Ovule number per plant, pollen‐ovule ratios, and fecundity were also examined. In spite of a very high number of ovules borne per plant, ranging from 683 to 1902, and sequential hermaphroditism, the maximum fecundity attained was ca. 60%, with production of 560 to 745 seeds per plant. Larger individuals produced larger and more numerous cormlets, a

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1987.tb00031.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractPlants of the genusArisaema(Araceae) have an abbreviated subterranean stem from which much information about their structure and life history is obtainable. In this study, the growth pattern of the stem, number of leaves per shoot, position of foliage leaf and of the lateral continuation shoot, nature of axillary bud and phyllotaxis were examined in more than 50 species ofArisaema, including evergreen tropical species as well as deciduous ones. The states of the characters are compared and related each other resulting in the recognition of seven types of stem patterns inArisaema. The life histories of the evergreen and deciduous species and the significance of stem morphology for the systematics ofArisaemaare briefly summarized.

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1987.tb00032.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractSpecies ofTrilliumin the subgenusPhyllantherumare either polymorphic for flower color, or monomorphic for flower color and related to a polymorphic species. This leads to the suggestion that polymorphic species may be the progenitors for monomorphic ones. For this to be true, it must be demonstrated that genetic divergence among flower morphs can occur within polymorphic populations. Genetic structure was assessed in a population ofT. sessilethat contains a polymorphism for flower color. A survey of 11 enzyme systems using starch gel electrophoresis revealed three polymorphic loci: 6PGD‐1, AAT‐1 and AAT‐2. Analysis of large and small scale spatial structure, stage classes, and flower color classes revealed significant genetic divergence in all instances. Spatial structure in the population is likely a result of genetic neighborhoods which can maintain populational variation via random genetic drift. Genetic divergence of the yellow flower color morph was probably initiated through genetic drift since the morph occurs in low frequencies. The results imply that the initial genetic divergence of species in the subgenus can arise within polymorphic popula

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1987.tb00033.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractA characteristic pattern of infection by a rust fungus,Uromyces erythroniiPass, on its host plant,Erythronium japonicumDecne. (Liliaceae) was observed in a field population for three years from 1981 to 1983. Due to the primary infection by teliospores ofU. erythroniiin the soil layer, spermogonia and aecia were formed on the abaxial leaf surface along the midrib ofE. japonicum.In the case of flowering individuals, however, spermogonia and aecia were only formed on the larger of the two leaves. An increase of individuals bearing telia was restricted by rapid decaying of leaf tissue of the host plant. A high percentage of rusted individuals was observed in theErythroniumpopulations, andU. erythroniiobviously has some effects on the growth of its host plant. However, its infection does not appear to be a direct cause of the death ofErythroniumindividuals in the field populations.

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1987.tb00034.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractThe ecological distribution and life history characteristics of threeRubusspecies, i.e.,R. palmatusThunb. var.coptophyllus(A. Gray) O. Kuntze,R. microphyllusL.f. andR. crataegifoliusBunge were investigated, with particular emphasis on the seasonal growth cycles, modes of the alternation of aerial organs, and patterns of dry matter allocation, and these features were critically compared with one another. It was found that seasonal changes of aboveground biomass are strongly related to the modes of cane alternation, to underground branching producing stolons, and to their dry matter allocation patterns. The modes of cane alternation, underground branching and dry matter allocation patterns were very similar inR. microphyllusandR. crataegifolius, taking about five months from May to September. ButR. palmatusvar.coptophyllusshowed much more gradual replacement of aerial organs, extending over seven months from May to December. These threeRubusspecies are often predominant in the early successional stages of pioneer communities which develop after cutting of forests in central Japan, and differentiations of the above‐mentioned life history traits found inRubusspecies seem to be related to the constraints inherent in their somewhat labile, changing environments, e.g., at the forest margin or clearings produced temporaril

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1987.tb00035.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractPredominant self‐pollination was confirmed in mixed populations ofTrillium apetalon(4x = 20, SSUU) andT. smallii(6x = 30, K1K1SSUU). In pollination tests conducted on both species from the Muroran (Mr) population, many good seeds were obtained from bagged flowers as well as open‐pollinated intact flowers. In striking contrast, fruits from castrated open‐pollinated flowers failed to give any good seeds. InT. smalliiin the Usu (Us) population, the same results were obtained for bagged and open‐pollinated intact flowers. On the other hand, fruits from castrated open‐pollinated flowers yielded only a few good seeds. Although both species were experimentally cross‐compatible in both directions, no interspecific hybrids have so far been found in nature. It may be possible that both species are isolated by predominant self‐pollinatioin even though their flowering sea

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1987.tb00036.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractThe life history ofEuryale feroxSalisb, observed in Akashi, Southwestern Japan, is described. Cleistogamous (CL) flowers appear from early July and precocious pollination occurs. Chasmogamous (CH) flowers are seen during a limited period between mid‐August and mid‐September. The abundance of CH flowers varies among populations and/or from year to year. Few insects visit CH flowers and self‐pollination occurs prior to anthesis. The number of seeds produced by CL flowers significantly exceeds that of CH flowers. Considering the shorter period of CH flower production and the lesser quantity of seed produced, the significance of CL flowers in the maintenance ofE. feroxpopulations must be considered greater than that of CH fl

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1987.tb00037.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractFor the understanding of morphological differentiation and recognition of natural groups in theSaussurea nipponicacomplex, 440 individuals from 19 populations were examined, especially by using statistical methods. The variation range of 16 morphological characters within and between populations were analyzed not only separately but also synthetically by Duncan's multiple range test, principal component analysis, and cluster analysis. Of the 16 characters examined, characters concerning plant size (height and diameter of stem, size of involucre, etc.) and involucral bract (length of involucral bract and recurved part of involucral bract) are suggested to be important to recognize natural groups. Five groups are recognized by a complex pattern of the morphological characters. They can be defined multivariately as natural groups having indegenous habitat and distribution range, and considered as subspecies ofS. nipponica.

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1987.tb00038.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY