bluuebunny/crossref_metadata_2025 huggingface dataset:
Promoter activity of human tissue inhibitor of metalloproteinase 2 gene with novel single nucleotide polymorphisms
Authors: HEGAB Ahmed E. , SAKAMOTO Tohru , UCHIDA Yoshiyuki , NOMURA Akihiro , ISHII Yukio , MORISHIMA Yuko , MOCHIZUKI Mie , KIMURA Toru , SAITOH Wataru , IIZUKA Takashi , KIWAMOTO Takumi , SEKIZAWA Kiyohisa
Published: February 2005

Objective:  The single nucleotide polymorphism (SNP) −418G > C in the TIMP2 gene promoter region has been shown to be associated with in chronic obstructive pulmonary disease (COPD). The purpose of this study was to search for novel single nucleotide polymorphism (SNP) in the TIMP2 promoter region around the −418G > C locus, and to investigate whether any of these SNP, including −418G > C, had an influence on TIMP2 transcription activity.

Methodology:  DNA sequencing was performed on a 689 base‐pair polymerase chain reaction fragment of the promoter region. The novel SNP were characterized and genotype analysis was performed for COPD and control subjects. A reporter gene assay was performed using the wild‐type promoter (−418G/−177C/+34C) and the mutant‐type promoter (−418C/−177T/+34A).

Results:  Nine novel SNP were identified. The SNP −177C > T and +34C > A were in complete linkage disequilibrium with −418G > C. The other seven SNP were not associated with COPD. No significant difference was detected in the reporter gene assay between the activities of the wild‐type and the mutant‐type promoters.

Conclusions:  The SNP −418G > C, −177C > T and +34C > A, might not themselves be functional from a transcriptional point of view in the development of COPD, but may be in linkage disequilibrium with other functional polymorphisms.
Pollination Ecology and Endemic Adaptation of Pedicularis howellii Gray (Scrophulariaceae)
Authors: Macior Lazarus Walter
Published: February 2005

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 previously studied.
Pollination Ecology and Endemism of Pedicularis pulchella Pennell (Scrophulariaceae)
Authors: Macior Lazarus Walter
Published: February 2005

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 physical environment.
The Life History of Euryale ferox Salisb. in Southwestern Japan with Special Reference to Reproductive Ecology
Authors: Kadono Yasuro , Schneider Edward L.
Published: February 2005

Abstract The life history of Euryale ferox Salisb, 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 of E. ferox populations must be considered greater than that of CH flowers.
Allozyme Variation within and between Populations of Coreopsis latifolia (Asteraceae)
Authors: Crawford Daniel J. , Post Barbara J. , Whitkus Richard
Published: February 2005

Abstract Enzyme electrophoresis was used to measure genetic variation in five populations of the rare diploid species Coreopsis latifolia which appears to be a relict taxon endemic to a small area of the southeastern United States. Gene diversity within the species as a whole is low compared to other species with similar ecological and life history traits. Also, gene diversity in C. latifolia is lower than nearly all other species of Coreopsis that have been examined. Larger populations contain significantly more variation at isozyme loci than do smaller populations. Populations of C. latifolia are deficient in heterozygotes relative to expected equilibrium values.
The Biology of Allium monanthum (Liliaceae) I. Polyploid Complex and Variations in Karyotype
Authors: Noda Shozo , Kawano Shoichi
Published: February 2005

Abstract Plants of Allium monanthum Maxim., whose gender expression are usually dioecious, but rarely hermaphrodite or gynomonoecious, proved to constitute a polyploid complex, consisting of diploid, triploid, and tetraploid individuals. The basic chromosome complement of this species consists of seven metacentric or submetacentric chromosomes and one acrocentric, the latter possessing a satellite on the short arm. Thus, the karyotype formula is expressed as 7V+11 (x=8). The diploid plants (2n = 16) were confined to central Honshu, Japan. Typical female plants possessed the standard karyotype, whereas male plants were heterozygous for two kinds of translocations. The 3x plants (2n=24) are somewhat widely distributed in the areas from the Kanto to Hokuriku district in Honshu. All female triploid plants possessed the standard karyotype. The geographical distribution of 4x plants (2n=32) which express mostly a female phenotype occurred nearly throughout the whole areas investigated; they are geographically isolated from the 2x plants. A majority of 4x plants had the standard karyotype. The remaining tetraploids were of the aberrant type, 4x/51, which has five acrocentric chromosomes, and two aneuploids 4x+1 and 4x‐1. Both 3x and 4x forms seem to be of autopolyploid origin. Three kinds of aberrant nucleolar chromosomes with an extra satellite or an inseried secondary constriction were found in the heterozygotes for translocations of 2x plants and also in some plants of the 3x form. These aberrant plants usually form their own homogeneous populations, but were somewhat scattered throughout the range in their distribution. Thus, these individuals are considered to have perpetuated these types of chromosome aberrations which originated in the remote past.
Life History Studies on the Genus Trillium (Liliaceae) V. Reproductive Biology and Survivorship of Three Declinate‐flowered Species
Authors: Ohara Masashi , Utech Frederick H.
Published: February 2005

Absract Three pedicellate‐declinate‐flowered species of Trillium (Liliaceae), T. vaseyi and T. flexipes, were studied for their life history characteristics, e.g., stage class structures of natural populations and reproductive features, including energy allocation to reproductive activities. The populations structures of all three species showed similar depletion structures characterized by a conspicuous decrease of individuals in the small juvenile stages, as was also observed in pedicellate‐erect‐flowered Trillium species However, with respect to reproductive characteristics, these three declinate‐flowered species showed different features from erect‐flowered species, although they belong to the same pedicellate‐flowered group. That is, these declinate‐flowered Trillium species exhibited low seed setting rates of 30% in T. catesbaei, 45% in T. vaseyi and 34% in T. flexipes, suggesting that they possess different mating systems from erect‐flowered species which showed high seed setting rates of 50–90%.
High Levels of Genetic Divergence among Populations in a Weedy Fern, Pteris multifida Poir.
Authors: Watano Yasuyuki
Published: February 2005

Abstract Intragametophytic selfing in the homosporous ferns has been viewed as an advantageous mechanism permitting colonization of distant, open habitats. However, there is little evidence for the generality of colonization through intragametophytic selfing. In this study, the genetic structure of Pteris multifida was determined using Wright's F‐statistics in order to detect the occurrence of this type of colonization. A high level of genetic divergence among populations (FST= 0.543) was found in P. multifida. This genetic divergence seems to be caused by frequent occurrences of colonization through intragametophytic selfing.
Reproductive Ecology of Ocimum americanum L. and O. basilicum L. (Lamiaceae) in India
Authors: Raju A. J. Solomon
Published: February 2005

Abstract Ocimum americanum and O. basilicum bloom once a year. They produce flowers over a long period, a few flowers being produced each day. The flowers of both are short‐lived (3‐4 hours), bisexual, zygomorphic, and chasmogamic with anthers dehiscing in the bud stage. The open flowers offer nectar and pollen as rewards and are visited and sternotribically pollinated by day‐flying animals. The blossoms are flag‐shaped, and the reproductive organs are close to the lower corolla lip. The stamens and stigma show movements immediately after anthesis and remain for 20–30 minutes and this may cause self‐pollination. Both species reproduce primarily through autogamy. Flowers are open during 5:30–13:30 hr in O. americanum and during 7:00–13:00 hr in O. basilicum. Certain bee species like Apis florea, A. cerana indica, Amegilla sp., and Pseudapis oxybeloies, and the butterfly Surandra queretroum are the most frequent and consistent visitors and can be pollinators for both plant species.
Germination Responses of Taraxacum platycarpum Seeds to Temperature
Authors: Washitani Izumi , Ogawa Kiyoshi
Published: February 2005

Abstract Germination responses of Taraxacum platycarpum seeds to temperature were examined under laboratory conditions to investigate the emergence‐season choice mechanism of the seeds. Almost all the newly collected seeds were non‐dormant. Under constant temperature conditions, maximum percentage germination (approximately 90%) was attained at temperatures 6–16°C, where simple linear relationships were observed between the temperature and the rates of germination, i.e. the reciprocals of the time taken to germinate by seed subpopulations with 10–80% germination. Thermal time required for germination of the subpopulations ranged from 600 Kh (degree Kelvin × hours) to 1500 Kh with a relatively constant base temperature of about 2.5°C. Lower limit temperature for germination was slightly below 6°C. Higher limit temperature for germination has the normal distribution with the mean ±SD of 19±2.5°C. Pre‐exposure of imbibed seeds to temperatures higher than the higher limit temperature for germination, 25 and 30°C, had no effect on the germinability and the rate of germination at a circa‐optimum temperature. Moist chilling treatment at 4°C caused an increase in the variation of germination rate within the seed population, but no evidence for dormancy‐inducing or breaking effects was obtained.
Observations on the Japanese Endemic Pseudopyxis (Rubiaceae‐Paederieae)
Authors: Puff Christian
Published: February 2005

Abstract Detailed information on the character states of Pseudopyxis depressa and P. heterophiylla, the only two representatives of the genus, are given. Particularly remarkable are the occurrence of both homo‐ (P. heterophiylla) and hetero(di)styly (P. depressa) and associated palynological differences, and the unusual fruits and diaspores, whose development is documented. Relationships between the two species are also discussed, and a section on the taxonomic position and history of the genus is included.
Dichogamy, Sex Allocation, and Mating System of Campanula microdonta and C. punctata
Authors: Inoue Ken
Published: February 2005

Dichogamy and sex allocation in several populations of Campanula microdonta and C. punctata were investigated with regard to their mating systems. Duration of the staminate phase differed among the populations: staminate phase was longer in self‐compatible (SC) and largely outcrossing populations than in self‐incompatible (SI) and outcrossing populations or in SC and largely inbreeding populations. Duration of the pistillate phase among the populations was less variable than duration of the staminate phase. Male reproductive effort decreased with increase of the estimated selfing rates. Male allocation (weight ratio of androecium to gynoecium or to total flower) may be used as an indicator of the breeding system. Within each population, small flowers allocate proportionately more resources to the androecium than to the gynoecium. Among populations, SC outcrossing populations tend to produce large ovaries, and SC inbreeding populations tend to produce small ovaries.
The Explosive Pollination Mechanism and Mating System of the WeedyHyptis suaveolens(Lamiaceae)
Authors: Aluri Raju J. S.
Published: February 2005

AbstractThe flower of the perennial shrubby herb,Hyptis suaveolens(L.) Poit. is representative of an explosive pollination mechanism. The carinal structure formed by the middle lobe of corolla lower lip conceals the stamens and stigma and does not open following the natural anthesis. Upon anthesis, the carinal lobe is under tension which is later released by wind or bees. The violent explosion of the carinal lobe caused by wind results in self‐pollination; by bees, it results in self‐ and cross‐pollination. Foraging activity of some bees which collect pollen from the anthers and stigma onH. suaveolensmay reduce the success of pollination.

The mating system involves both autogamy and allogamy. Both require explosion of carinal lobe for pollination. The flexibility of the mating system is considered a safeguard ensuring its ruderal nature for weediness.
Comparative Ecology of Rubus Species (Rosaceae) II. Reproductive Characteristics of Three Rubus Species, R. palmatus var. coptophyllus, R. microphyllus and R. crataegifolius
Authors: Suzuki Wajirou
Published: February 2005

Abstract The reproductive characteristics of three Rubus species (R. palmatus Thunberg var. coptophyllus (A. Gray) O. Kuntze, R. microphyllus L.f., and R. crataegifolius Bunge) were critically investigated using materials collected from the forest floor of an 85‐year‐old Hinoki (Chamaecyparis obtusa) plantation in central Honshu, Japan. The underground branching patterns of these species were also investigated at the nursery. R. microphyllus produced the largest number of fruits in the same cane size among the three species (164 fruits per cane of 300 cm3 in D02H). However, the largest number of seeds produced per cane was in R. crataegifolius, where the maximum seed number attained 74,500 per cane, which was twice as many as those of the other two species. There was no apparent difference in dry matter allocation to fruits in these species. The three species produced numerous suckers by underground branching, forming large clones. In the open site at the nursery, the number of suckers produced by underground branching increased exponentially. On the other hand, in natural populations occurring in closed sites, the number of suckers produced by underground branching in the three species was by contrast much smaller. Three Rubus species proved to possess similar perennation as well as reproductive strategies, although R. palmatus var. coptophyllus shows much lower seed production and slower sucker production than the other two species.
Evolution of the Selfing Rate and Resource Allocation Models
Authors: Iwasa Yoh
Published: February 2005

Abstract First, evolutionary theories of selfing of terrestrial plants are reviewed briefly. The evolution of the selfing rate is controlled mainly by (1) the benefit of enhanced genetic relatedness to seeds and (2) the cost of lowered fitness of selfed offspring (inbreeding depression), being modified by (3) fertility assurance under pollen limitation, (4) reduced performance as pollen donor, (5) reduced expenditure to male function, and (6) lowered genetic recombination. Models of the joint evolution of selfing and inbreeding depression predict either strong outcrossing or predominant selfing. Although wind‐pollinated plants fit the prediction, some animal‐pollinated species have intermediate selfing rates, refuting the theory.

Second, three resource allocation models are analyzed, in which an individual plant optimally allocates limited resources to outcrossed seeds, selfed seeds, and to energy reserves for the next year. The first model explains how the number of outcrossed and selfed offspring change with plant size when they differ in dispersal distance. The second model predicts that, in a disturbed habitat, the plant is likely to be annual and to produce both selfed and outcrossed seeds; in contrast, in a stable habitat, the plant tends to be perennial and to abort selfed seeds selectively. Hand pollination may increase seed production for perennials but not for annuals. The third model explains the observed difference between animal and wind pollinated plants in the out‐crossing rate pattern by the difference in the way pollen acquisition increases with investment.
Differentiation Patterns of Reproductive Systems in the Genus Trillium
Authors: Ohara Masashi , Kawano Shoichi , Utech Frederick H.
Published: February 2005

Abstract The differentiation patterns of reproductive systems, including breeding and pollination systems, and perennation strategies of the genus Trillium were critically studied. The pedicellate‐ and sessile‐flowered species with different floral morphologies and ecological distributions exhibited distinct modes of reproductive systems in relation to their habitat conditions. The pedicellate‐flowered species occurring in stable mesic temperate deciduous forests reproduce exclusively by seeds, while sessile‐flowered species growing in the alluvial flood plain habitats depend to a large extent on vegetative reproduction to compensate for the insufficient sexual reproduction under ecologically unstable conditions, e.g., frequent disturbance due to flooding. These sessile‐flowered species are characterized by low ovule numbers, subsequent low seed outputs and low fecundity levels. In contrast to the sessile‐flowered species, the pedicellate‐erect‐flowered species showed very high seed setting rates of over 50%. Breeding experiments for four Japanese species suggest that, although they substantially possess the capability of both inbreeding and outbreeding, the high fecundity levels are maintained by predominant inbreeding system. Furthermore, resource levels in the stock organs of these species obviously determine fecundity levels. As a consequence the amount of reserved food in the rhizomes transferred to the next season is determined, which gurantees a continuous reproductive activity of a given individual plant.
The Breeding Structure of Tropical Tree Populations
Authors: Hamrick J. L. , Murawski Darlyne A.
Published: February 2005

Abstract Several approaches were used to study the breeding structure of tropical tree populations located on Barro Colorado Island, Republic of Panama. Allozyme analyses of 16 woody species indicated that the distribution of genetic diversity among collection sites was closely associated with the species’breeding system and seed dispersal mechanism. Low levels of diversity observed among collection sites separated by 1–2 km indicate that intersite gene flow is high. Estimates of the proportion of outcrossing obtained for seven species indicated that the majority (6) were highly outcrossed. A significant amount of tree to tree heterogeneity in pollen allele frequencies also existed for each outcrossing species. Degree of heterogencity in pollen allele frequencies received by maternal trees was negatively associated with flowering tree density. In the mixed mating species, Cavanillesia plantanifolia, the proportion of selfing was closely related to flowering tree density. A significant proportion of the pollen received by individuals of these eight species came from relative few individuals. Pollen movement within populations was estimated for two canopy species. Long distance pollen movement (>750m) was extensive (>20%) in both species. The breeding structure of these tropical species appears to be a mixture of near‐neighbor (30%–50%) and long‐distance pollen movement (10%–25%). If this pattern is typical of tropical tree species, it has important implications for the genetic structure of populations as well as for the design of conservation areas.
Breeding Systems of Three Tree Ferns: Alsophila firma (Cyatheaceae), Cyathea stipularis (Cyatheaceae), and Lophosoria quadripinnata (Lophosoriaceae)
Authors: Soltis Douglas E. , Soltis Pamela S. , Smith Alan R.
Published: February 2005

Abstract Breeding‐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), and Lophosoria quadripinnata (Lophosoriaceae) using enzyme electro‐phoresis. Genetic data were used to estimate intragametophytic self‐fertilization and F, 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 strategies, and environments.
Species Biology of Primula sieboldii for the Conservation of its Lowland‐habitat Population: I. Inter‐clonal Variations in the Flowering Phenology, Pollen Load and Female Fertility Components
Authors: Washitani Izumi , Namai Hyoji , Osawa Ryo , Niwa Masaru
Published: February 2005

Abstract Intra‐population variations of several characteristics related to fertility were assessed for a nature‐reserve population of Primula sieboldii in 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 of P. sieboldii on 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 inbreeding habit.
Variation of Relative Growth Rate and Survival in Ecologically Contrasting Populations of Agrostis stolonifera
Authors: Kik C. , Jongman M. , van Andel J.
Published: February 2005

Abstract Significant differentiation in relative growth rate (RGR) was found among three ecologically contrasting populations of Agrostis 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 site.
Morphometric and Isozyme Analysis of the Genus Hosta (Liliaceae) in Korea
Authors: Gi Chung Myong , Jones Samuel B. , Hamrick J. L. , Gi Chung Hye
Published: February 2005

Abstract The 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 Korean Hosta populations and from two populations of H. tsushimensis N. 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. yingeri S. B. Jones (Taehuksan, Sohuksan, and Hong islands); H. capitata (Koidz.) Nakai (southern Korea); H. clausa Nakai (central and northern Korea); H. minor (Baker) Nakai (southeastern Korea including Wan and Kojae islands); H. venusta F. Maekawa (Cheju Island); and H. jonesii M. 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 of H. venusta from H. 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 habitats.
Pollination Ecology of Pedicularis megalantha D. Don (Scrophulariaceae) in the Himachal Himalaya
Authors: Macior Lazarus Walter , Sood Sarvesh K.
Published: February 2005

Abstract In the summer of 1990, the pollination ecology of Pedicularis megalantha was studied in the montane‐subalpine spruce‐fir forest zone (2750‐3050 m) on the north slope of Mt. Huttoo at Narkanda, Himachal Pradesh, in the Indian Himalaya. Its yellow, long‐tubed, nectarless flower with a curled rostrum overarched by a broad, inverted lower corolla lip was pollinated exclusively by Bombus albopleuralis and B. tunicatus workers hanging inverted from the corolla and vibrating pollen from introrse anthers concealed within the galea and releasing pollen through a small ventral opening in the galea base. The stigma, protruding from the tip of the rostrum, contacted pollen deposited on the ventral side of the insect's thorax. Corbicular pollen loads from P. megalantha pollinators indicated equal numbers of monolectic and oligolectic foragers. P. megalantha appeared to suffer from competition for pollinators by Cynoglossum wallichii at one site but to be favored in a mixed plant community with nectariferous species offering a forage resource complementary to Pedicularis pollen. As in P. punctata, the long, nectarless corolla tube of P. megalantha appears to function in extending the rostrate vibration pollination mechanism beyond the plant's foliage, which would interfere with its function. It is not an adaptation for nectar‐foraging lepidopteran pollinators. P. megalantha was also found to be a root hemiparasite.
Allozyme Variation within and between Populations of Coreopsis intermedia (Asteraceae)
Authors: Cosner Mary Elizabeth
Published: February 2005

Abstract Enzyme electrophoresis was used to measure genetic diversity in two populations of Coreopsis intermedia of section Coreopsis, a rare species endemic to a small area of Texas and Louisiana. Genetic diversity is higher in C. intermedia than has been reported for many other geographically restricted species. C. intermedia contains levels of genetic variation comparable to those of other species in section Coreopsis, and a greater amount of diversity than either the rare congener, C. latifolia (section Silphidium), or the Florida endemic, C. leavenworthii (section Calliopsis). The two populations, although greatly different in size, exhibited similar levels of genetic diversity.
Pollination Ecology and Endemic Trends inPedicularis bracteosavar.atrosanguineaPennell & Thompson (Scrophulariaceae) in North America
Authors: Aluri Raju J. S. , Robart Bruce W.
Published: February 2005

AbstractPedicularis bracteosavar.atrosanguineaoccurs locally in association withP. racemosaorP. groenlandicain the Olympic Mountains in Washington. Other plant species, e.g.,Polygonum bistortoides, Lupinus argenteusvar.parviflorusandValeriana sitchensiscompete for space and bumblebee pollinators within the study area. Pollinator sharing, resulting from such competition, may increase the frequency of unvisited flowers ofP. bracteosavar.atrosanguinea. P. bracteosavar.atrosanguinea, with blood purple nectariferous flowers, is presumed to lack intense reflections of blue spectral components from its corollas in attracting bumblebees compared to those ofP. racemosaandP. groenlandica. Six species of bumblebees (Bombus) and cuckoo bees (Psithyrus) pollinateP. bracteosavar.atrosanguinea. Of these,Bombus mixtusandB. occidentalisoccur in higher frequencies and are the major pollinators ofP. bracteosavar.atrosanguinea. Queen and larger worker bumblebees pollinate nototribically as they probe for nectar, while smaller worker bumblebees pollinate sternotribically while scraping pollen from anthers deeply hidden in the dome‐shaped galea. Corbicular pollen loads of bumblebees collected in the study area containPedicularispollen alone/in combination ofPolygonum, Valeriana, Lupinus, ErigeronandBidens, or exclusively ofPolygonumorValeriana. P. bracteosavar.atrosanguineadoes not suffer seriously from deficient pollination but seedlings resulting from pollinated flowers may be subjected to natural selection pressure exerted by colonial plant species for space.P. bracteosavar.atrosanguineadoes not propagate asexually but resumes aerial growth seasonally from the self‐same underground root stocks. If seedlings are under continuous selection pressure for lack of space,P. bracteosavar.atrosanguineais presumed to regenerate primarily by perennial root stocks. This behavior may favor endemism inP. bracteosavar.atrosanguinea.
Sex Allocation Ratio in a Wind‐Pollinated Self‐Incompatible Monoecious Tree, Alnus firma Sieb. et Zucc. (Betulaceae)
Authors: MURAKAMI NORIAKI , MAKI MASAYUKI
Published: February 2005

Abstract Biomass sex allocation of Alnus firma, a wind‐pollinated self‐incompatible monoecious tree species, was directly measured at the inflorescence (prezygotic) stage. Sex allocation ratio at the fruit stage was estimated from the number of female inflorescences, percent fruit production, and the mean dry weight of a female inflorescence and a fruit catkin. Investment in male function far exceeds that in female function at the prezygotic stage. When the costs of fruit catkins and seeds were included in the estimation of female function, then the sex allocation bias was reversed towards female. Intrapopulational variation of the sex allocation ratio with respect to tree height and size was also investigated. A strong negative correlation was observed in both cases, although a positive relationship has been predicted by theorists and some previous empirical data have supported this prediction.
Biosystematic Studies in Disporum (Liliaceae‐Polygonateae) IV. Karyotype Analysis of some Asiatic and North American Taxa with Special Reference to their Systematic Status1)
Authors: TAMURA MINORU N. , UTECH FREDERICK H. , KAWANO SHOICHI
Published: February 2005

Abstract Fifteen Asiatic and four North American taxa of the genus Disporum (Liliaceae‐Polygonateae) were karyologically examined. The chromosome numbers and karyotypes of D. multiflorum (2n= 14), D. sessile var. sessile f. minus (2n= 16), D. sessile var. micranthum (2n= 16), and D. taipingense (2n= 16) were determined for the first time. Thirteen additional chromosome counts and karyotype analyses were made for the following 11 Asiatic Disporum taxa (Section Disporum): D. calcaratum (2n= 14 and 16‐a new count), D. cantoniense (2n= 14 and 16), D. kawakamii (2n= 16), D. longistylum (2n= 16), D. lutescens (2n= 16), D. sessile var. sessile f. sessile (2n= 16), D. shimadai (2n= 14), D. smilacinum var. smilacinum (2n= 16), D. smilacinum var. ramosum (2n= 16), D. uniflorum (2n= 16), and D. viridescens (2n= 16 + 1B‐a new count).

The karyotypes of four North American taxa (Section Prosartes) were reported for the first time, although the same chromosome counts had been previously known for each taxon: D. hookeri (2n= 18), D. lanuginosum (2n= 18), D. maculatum (2n= 12), and D. smithii (2n= 16). D. maculatum possesses a very characteristic satellite on the long arm of the fifth subterminal chromosome; the karyotype of D. smithii (x= 8) is also characterized by possessing a minute satellite on the short arm of the fifth pair and also by a secondary constriction on the short arm of the sixth pair.

One of the most noteworthy findings made in the present study is that the species of Section Disporum and Section Prosartes possess conspicuously distinct cytological features in the size of resting nuclei and cells, interphase chromosomes, and mitotic prophase and metaphase chromosomes. The plants of Section Disporum have distinctly larger resting nuclei and cells than those of Section Prosartes; Section Disporum possesses a typical homogeneously diffused type (= densely diffuse type according to Tanaka, 1977) of interphase chromosomes, while Section Prosartes has a prochromosome type; the condensation pattern of their prophase chromosomes is of a continuous type in Section Disporum, while a proximal type occurs in Section Prosartes; Section Disporum possesses distinctly larger sized metaphase chromosomes, as compared with Section Prosartes. All of these karyological differences described above strongly support D. Don's original concept (1839, 1841) of treating Disporum and Prosartes as two separate genera.
The Role of Tree Gaps in Maintaining the Population Structure of a Woodland Herb: Cynoglossum virginianum L.
Authors: WHIGHAM DENNIS F. , O'NEILL JAY , CIPOLLINI MARTIN
Published: February 2005

Abstract Tree gaps may be important habitats for the establishment and spread of understory herbs in eastern (US) deciduous forests. Data from past studies, however, have not shown any clear patterns for either species diversity or increased percent cover. The lack of clear patterns of response to gaps by herbs may be due to evolutionary differences among species or, in part, due to the fact that most studies have been short‐term and long‐term patterns have, therefore, not been observed. In addition, few studies have considered the responses of individual genets and/or ramets. We have been conducting a long‐term study of Cynoglossum virginianum, now in its 16th year, to determine subpopulation and individuals' responses in gap and non‐gap habitats. A larger percentage of individuals flowered in the gap subpopulation shortly after it was created. Seed production rates were also higher in the gap subpopulation. The long‐term benefits gained by the short‐term flowering response have, however, been few as all but two of the seedlings produced within a few years of gap formation have died. In addition, all of individuals that flowered and produced seeds decreased in size and most have remained in the smaller size classes. In addition, only one of the individuals in the gap subpopulation has flowered since the initial flowering response while plants in non‐gap subpopulations have flowered and produced seeds throughout the study period. Gaps may only be beneficial to C. virginianum if seeds are dispersed into non‐gap areas or if seeds can remain dormant in the soil until conditions are more suitable for seedling survival.
Population Interactions and the Determinants of Population Size
Authors: WATKINSON ANDREW R. , LINTELL‐SMITH GAIL , NEWSHAM KEVIN K. , ROWCLIFFE J. MARCUS
Published: February 2005

Abstract The flux of individuals within populations is dependent upon six controlling processes: the intrinsic rate of increase of the plant, intraspecific competition for resources, interspecific competition, natural enemies, mutualisms and refuge effects such as the immigration of seeds from other populations. Although population interactions are generally believed to play a major role in determining the flux of individuals within populations, little attempt has been made to quantify the strength of these interactions and their role in the dynamics of populations. In this paper we examine the role of competition, herbivory and mutualistic interactions in determining the dynamics of a range of annual plant species. Firstly, it is shown that the dynamics of three weed species (Bromus sterilis, Galium aparine, Papaver rhoeas) in an experimental community in an arable cropping system of winter wheat are determined primarily by the rapid population growth of B. sterilis. Interactions between the species play a minor part in the dynamics of the system. Secondly, it is shown that current levels of grazing by overwintering populations of brent geese have a minor impact on the abundance of Salicornia europaea, but that increased grazing has the potential to reduce abundance and increase the instability of S. europaea populations. This is a consequence of the aggregative response of the geese, which results in an increasing proportion of the seeds of S. europaea being eaten as plant density increases. Thirdly, it is shown that there is a complex interaction between root pathogenic and arbuscular mycorrhizal fungi in natural field populations of Vulpia ciliata and that the benefit of mycorrhizal fungi to the plant is in providing protection against pathogens.
Scale, Experimental Design and the Detection of Ineterspecific Competition within Plant Communities
Authors: FIRBANK L.G. , LINTELL‐SMITH G. , McCLOSKEY M. , SMITH J.M. , WEBB D.J.
Published: February 2005

Abstract We report preliminary results of a series of experiments designed to explore the importance of interspecific competition within arable weed communities at different scales. Competition hierarchies were apparent from a pot experiment with different levels of nutrients and water. Two field experiments looked at Bromus sterilis, Galium aparine and Papaver rhoeas in winter wheat in the field, in a range of combinations and management treatments, and a fourth field experiment included a wider variety of species. There was little effect of fertilizer on population behaviour in the the field. Bromus increased around ten fold per year on minimum‐tilled plots, regardless of other treatments. Galium increased on organically‐fertilized and minimum‐tilled plots, but only in the absence of Bromus. Papaver densities remained low, but again were depressed in the presence of high densities of Bromus. Taken together, the experiments demonstrate the existence of competition between weed species. However, as the design of the experiment increased to include greater levels of environmental variation, so competition became more difficult to detect, and less useful for interpreting the results than knowledge of the biology of the individual species. At the scale of interest to the farmer, the level of competition is not a good predictor for weed population dynamics.
Diversity and Coexistence of Sonoran Desert Winter Annuals
Authors: VENABLE D. LAWRENCE , PAKE CATHERINE E. , CAPRIO ANTHONY C.
Published: February 2005

Abstract Annual plants make up ca. 50% of local floras in the Sonoran Desert. As with most plant communities, there is no shortage of potential coexistence generating mechanisms, and several mechanisms are likely contributors to coexistence at different spatial scales in the Sonoran Desert, e.g. spatial heterogeneity and the behaviors of predators and grazers. We explore one mechanism of likely importance for desert annuals: temporal environmental variation. It is widely recognized that coexistence is promoted by temporal variation if species such as desert annuals have “temporal niches” in the sense that each has years in which it out‐performs the others. It is usually suggested that some resistent life‐history stage, such as a seed bank, is also necessary to buffer each species from the negative population dynamic impact of unfavorable years. Using ten years of demographic data, we document the large year‐to‐year variation in population dynamics of desert annuals and show that ten species respond differently to temporal variation. Competition experiments document reversals in competitive superiority. Also, all species have a between‐year seed bank, such that only a proportion of the seed bank germinates in any given year. Thus this system meets our intuitive requirements for variance‐based coexistence. Dynamic models of this system demonstrate that subtle aspects of the species biology determine whether coexistence criteria are actually met. Specifically, variable germination fractions are required and coexistence is most readily favored with “predictive” germination. Germination fractions in this system do vary among years in a species specific fashion. Also, for the three years of available data, germination was predictive, in that each species had greater germination fractions in year of greater demographic success. Thus all of the population dynamic elements necessary for temporal variance mediated coexistence seem to be present in this system.
Pollen‐mediated Gene Flow in a Population of Cynanchum grandifolium var. nikoense (Asclepiadaceae)
Authors: MAKI MASAYUKI , MASUDA MICHIKO
Published: February 2005

Abstract Inter‐ and intrapopulation pollen‐mediated gene flow was estimated in a population of Cynanchum grandifolium var. nikoense by paternity analysis of all the seeds set in 1990. By the simple exclusion procedure, the rate of genes migrating by pollen into this population was estimated to be 0.083; this value is lower than that estimated in most previous studies. Frequency distributions of intrapopulation pollen‐mediated gene flow distances estimated by different methods of paternity analysis were platykurtic, and the estimated distances of realized gene flow were smaller than the interplant distance.
Molecular Systematics of Liliaceae — Asparagoideae — Polygonatae. I. RFLP Analysis of cpDNA in Several Asiatic Disporum Species
Authors: SHINWARI ZABTA KHAN , TERAUCH RYOHEI , KAWANO SHOICHI
Published: February 2005

Abstract Phylogenetic relationships among 11 species in the genus Disporum were assessed by RFLP analysis of chloroplast DNA and their taxonomic status was re‐evaluated in the light of molecular, karyological as well as morphological data available at present. Among cpDNAs from 17 plants of 11 species, 16 mutations were detected using 14 restriction enzymes and heterologous cpDNA probes. Restriction site data were analyzed cladistically, and a majority rule consensus tree was obtained. Species fell into four groups based on cpDNA, (1) a group containing seven species, D. uniflorum, D. taipingense, D. lutescens, D. sessile, D. kawakamii, D. multiflorum, and D. shimadai; (2) containing one species D. viridescens; (3) containing two species D. smilacinum and D. cantoniense var. skimmense; (4) containing D. leucanthum. Among these groups the first one has two clades with high probability rate. The results suggest that D. lutescens belongs to the “D. sessile group” rather than the “D. smilacinum group”. But, the separation of D. viridescens and D. smilacinum into two groups as revealed by the present analysis is somewhat controversial, since both D. viridescens and D. smilacinum share a number of morphological and karyological characters in common. Intraspecific cpDNA variation of D. sessile was also analyzed.