摘要:

AbstractGrowth and allometry were analyzed for populations ofMonophyllaea hirtellaMiqand M. horsfieldiiR. Br. (Gesneriaceae), forest floor herbs that have only one cotyledonous leaf throughout life, in an equatorial rain forest in West Sumatra.Monophyllaeapopulations consisted of individuals of various sizes up to 30 g dry weight and 50x70 cm in leaf width and length. The relative growth rate (RGR) declined with size to an asymptotic value of 0.015–0.018 gg‐1week‐1for large individuals at sexual maturity (>2 g dry weight). The size‐RGR relation did not differ among observations at three differen times of year and between two species in different habitals, indicating that it takes 4.6 years for seedlings to attain sexual maturity and 6.4 years to reach 10 g dry weight. Irrespective of embryonic organization ofMonophyllaea, clear allometry existed among organs. Net assimilation rate was constant for juveniles and increased with size for adults. Decline of both the specific leaf area and the ratio of assimilate allocation to leaf caused the decrease of RGR with size. Reproductive allocation was 31% to reproductive organs and at most 5% to seeds in net production in a large individual of 20 g dry

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00020.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractClonal variation in the sprouting pattern of tubers inEleocharis kuroguwaiOhwi was studied, using 39 clones collected within a longitudinally narrow belt from Wakasa Bay to the Kii Peninsula of Japan and one of “Ohkuroguwai”, a cultivated form.The sprouting pattern of tubers and the relationship between sprouting time and other tuber characteristics varied noticeably among clones. Based on the polygonal graphs of × (mean), x̄ (standard deviation), g1(skewness) and á (kurtosis) of the sprouting time, the sprouting pattern of 40 clones could be divided into the following three groups. Group A: x̄ and α were small, but g1and a' were generally great; almost all tubers sprouted early and simultaneously. Group B: x̄ and α were greater, but g1and a' were smaller than Group A; the majority of tubers sprouted quickly, but the rest of the tubers sprouted gradually. Group C: x̄ and α were very large, g1was small, but a' showed a comparatively large negative value; all tubers sprouted gradually over a long period.Groups A and B were represented by the irrigation pond group from the Banshu Plain and by the Ohshima Island group in the paddy fields of the southern extremity of the Kii Peninsula. Clones from the paddy field group and from the plain group, both referable to typical rstrategists, exhibited various sprouting patter

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00021.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractLife history characteristics, e.g., stage class structures of natural populations and associated reproductive characteristics, were studied for six sessile‐flowered, diploidTrillium(Liliaceae) species that are restricted to the Coastal Plain region of the southeastern United States.These sessile‐flowered species reproduce primarily by vegetative propagation. Leaf area measurements were used to categorize stage class distributions of natural populations. Populations propagating mainly by vegetative reproduction had non‐sigmoidal, convex‐shaped population structures with most plants being in the intermediate stage classes. Low numbers of individuals in smaller stage classes and an abundance of intermediate sized individuals are due to the fact that vegetative propagules are the primary method for maintenance of local populations.Characteristics associated with sexual reproduction were also examined. Seed output averaged about 20 seeds per plant, except for T.lancifoliumwhich produced 9.7 seeds on the average. Seed setting rates varied between 15.61–44.15% and mean seed weight varied from 4.89 to 10.75 mg. The dominance of vegetativeversussexual reproduction may be due to the fact that all six species occur in ecologically unstable flood plain

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00022.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe population struaures, spatial and temporal distributions of individual plants, and survivorship were investigated in four JapaneseTrilliumspecies (Liliaceae),T. kamtschaticum, T. tschonoskii, T. apetaion and T. smallii.The stage class structures of these four species based on leaf area categories all showed similar depletion curves associated with an increase in stnge class. That is, there occurs a conspicuous decrease in early juvenile stages, subsequent leveling‐off in the intermediate stages and a slight decrease again in the larger stages. The high mortality in juvenile stages was also confirmed by continuous observations in the permanent plots established on the forest floor forT. kamtschaticumandT. apetalon.Furthermore, the analysis of spatial distribution patterns forT. kamtschaticumandT. apetalonrevealed successive distributional changes from under‐dispersed (aggregated) to random or overdispersed with the progress of the growth st

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00023.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractPedicularis howellii, endemic to the Siskiyou Mountains of California‐Oregon, is a root hemiparasite obligately dependent upon bumblebee pollinators that remove pollen by vibration from its short‐tubed, nectarless, rostrate flowers, which reflect visible and ultraviolet (360nm) light attractive toBombusforagers. All sixBombusspecies in the study area pollinated the plant, but only on P.howelliiandP. racemosa were B. mixtus workersthe most abundant pollinators among the seven bumblebee‐pollinated plants studied, includingDelphinium decorum, Dodecatheon jeffreyi, Penstemon newberryi, P. shastensis, and Phacelia heterophylla. Analysis of corbicular pollen loads of Bombuspollinators indicated that pollen foragers on Pedicularis species were less pollen‐constant than all other bumblebee pollinators. AlthoughP. howelliiandP. racemosablooming periods overlapped slightly, phenological isolation of blooming periods of plants sharing the same pollinators was not evident. Chemical soil analysis of its habitat and quadrat analysis of the population structure ofPedicularis howelliiindicated that the plant grows in a moderately fertile forest soil and is restricted to the edge of forest canopy openings where sunlight favors development of plants to the flowering stage. The endemism ofP. howelliiis related to a similar “edge effect” survival ofP. furbishiaein a boreal forest riparian habitat previou

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00024.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractPedicularis pulchellaPennell, endemic to sparsely vegetated areas of alpine tundra scree in southwestern Montana and northwestern Wyoming, was found to be roat‐hemiparasitic and obligately dependent for its pollination upon bumblebees of three non‐tundra species that forage primarily in an inverted position for pollen scraped from anthers concealed in the galea, This sternotribic pollination syndrome is considered related to the short (5–6mm) proboscides of pollinators on flowers with deep (12.4mm), nectariferous corolla tubes and favoring pollen as an insect attractant. Photographic and spectropholomelric analysis of the red‐purple floral color included prominent blue corolla and ultraviolet calyx reflections corresponding to dominant colors of bumblebee visual spectra. Nectar analysis by thin‐layer chromatography and refractomctry indicated, respectively, the presence of fructose and sucrose, and a sucrose‐equivalent concentration of dissolved solids exceeding 50%; both coincide with the general pattern of the genus. Analysis of pollen from corbicular loads ofP. pulchellapollinators indicated relatively low pollen‐constancy of insects and substantial foraging association with Vaccinium in the montane‐subalpine zone. By contrast, pollinators on P. cystopteridifolia and Phyllodoce glanduliflora in a diverse tundra plant community on rich alpine turf revealed broad pollinator spectra (7–8 species), high pollen‐foraging constancy on Pedicularis, and high nectar‐foraging frequency onPhyllodoce: The pollination ecology and endemism ofPedicularis pulchtellaare interpreted in terms of resource sharing, spatial competition of plant species, and selective stress of the

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00025.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractPlasticity in growth, reproductive energy allocation (RA), and reproductive output were studied inGlycine maxMerr. Cv.Enrei(Leguminosae) grown under varying densities and soil nitrogen levels.Marked plastic responses were detected in individual biomass, the patterns of resource allocation to total reproductive structures (RA) and also to propagules, reproductive outputs, and propagule weight under changing densities and soil nitrogen levels. Plants cultivated at higher densities exhibited proportionately lower individual biomass, lower RA, lower seed output, and smaller seed size in response to increasing density and decreasing soil nitrogen levels, although some deviations were observed, especially in the highest density plot with no fertilization. Differences due to different N‐levels were not as great as those to changing density, which may in part be due to the fact that soybean has nitrogen‐fixing bacteria in root tubercles, just as in any other Leguminosae. Fecundity was also maintained at the similar high rates of 80–97% in all plots examined, although slight but steady decreases were noted with increasing density. This resemblance in fecundity may be due to its strong inbreeding system.Another important finding was that seed production under limited resource availability, notably lack of ample solar radiation due to strong interference at higher density plots, is exceedingly costly. This was most clearly exhibited by a sharp increase in relative energy partitioning to a single propagule in response to the increased density, the relative energy cost to a single propagule (RA) increasing from one to seven‐fold. The results obtained in this study coincide well with the findings made in other plants, e.g.,Helianthus annuus, Oryza sativa, andCoix ma‐yuen, with the same experimenta

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00026.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractTotal seed yield per plant in one season was differentiated neither betweenEpimedium diphyllumand theE. grandiflorumcomplex (E. grandiflorumandE. sempervirens), nor between these two groups and one of their hybrid derived species,E. trifoliatobinatum. Total ovules per plant and seed‐set rate per capsule (SR) did not vary greatly between these species, and seed weight (SW) was almost the same between them. The number of flowers per inflorescence (F) was also constant. However, the remaining reproductive component characters, ovule number per ovary (O) and inflorescence number per plant (I), were differentiated between the three taxa. These two characters were negatively correlated and a trade‐off relationship occurred under the constant total seed yield (=O×F×I×SR×SW). Ovule number per ovary was highly correlated with spur length of the flower. During the course of the hybrid speciation ofE. trifoliatobinatum, selection pressure by pollinators on intermediate spur length seems to have favored plants with an intermediate ovule number. On the other hand, this selection pressure counteracted the increase of the inflorescence number under the trade‐off. The resultant seed yield ofE. trifoliatobinatumdid not differ from that of the parental species, but the pattern of ovule allocation to ovaries (capsules) wa

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00027.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractField experiments on an orchid,Platanthera mandarinorumssp.hachijoensis, were carried out to investigate the effects of variations in spur (nectary) length and pollinator activity on reproductive success (RS) of individual plants. Experiments comprised two kinds of treatments: spur shortening and bagging to restrict pollinator activity. Plants with a natural spur lengths range show nearly equal RS, whereas plants with shortened spurs had decreased RS proportional to spur length reduction. Pollinaria attachment (a measure of male RS) to the pollinators seems to demand stricter morphological correspondence than pollen receipt (female RS). Decrease of male and female RSs in spur‐treatments was smaller in the case of high pollinator activity than low pollinator activity. Results of the bagging experiments indicated that female RS was greater than male RS in cases of high pollen carryover. These facts suggest that (1) fecundity selection operates more intensely on both male and female functions in the case of low pollinator activity and more intensely on the male function in the case of high pollen carryover, and (2) individuals with different spur lengths in natural populations have nearly equal probabilities of RS after excluding the extreme variants through the reduction of male R

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1986.tb00028.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY