Leaf flavonoid patterns in the genus Tricyrtis (Tricyrtidaceae sensu stricto, Liliaceae sensu lato)

In a leaf flavonoid aglycone survey of 19 Tricyrtis species, the flavone lulcolin was detected in 16% of the taxa and the flavonols myricetin, qucrcetin, kaempfcrol and isorhamnetin in 32%, 63% and 68% and 58% of the sample, respectively. Kaempfcrol occurred more frequently than qucrcetin in sections Hirtae and Tricyrtis. Section Brachycyrtis was characterized by the presence of lulcolin, while flavoncs were absent from sections Flavae, Hirtae and Tricyrtis. Myricetin was found only in T J'ormosana and T. hirta (section Hirtae) and in T affirm and T. macropoda (section Tricyrtis). This is the first report of myricetin in Tricyrtis and in the Liliales. Also the co-occurrence of flavones and flavonols within the same plant, as in 7. ishiiana var. surugensis and T macrantha , is a rare event in this order. The flavonoid data are congruent with data from morphology, anatomy and molecular analysis in indicating the separation of section Brachycyrtis from the other three sections and in supporting a close relationship between sections Hirtae and Tricyrtis.     

Comparison of genetic variation and differentiation using microsatellite markers among three rare threatened and one widespread toad lily species of Tricyrtis section Flavae (Convallariaceae) in Japan

Genetic diversities were examined using six microsatellite markers amplifiable in three rare and one widespread species of Tricyrtis section Flavae, which are endemic to Japan. Contrary to a general expectation, the three rare species, Tricyrtis flava, Tricyrtis ohsumiensis and Tricyrtis perfoliata, have comparable genetic variation at the species level to that of the widespread Tricyrtis nana. This is probably because T. nana has not sufficiently recovered genetic diversity from the bottleneck at speciation or because recent range contractions have occurred in the three rare species. Genetic diversity at the population level was smaller in the putative selfing species T. nana than in the other three outcrossing species. Compared with a preceding study using allozyme markers, the genetic diversity in microsatellite loci was considerably larger, probably resulting from higher mutation rates at the microsatellite loci. Owing to the high genetic diversity of the microsatellite markers, genetic differentiation among populations could be estimated even in T. nana with little allozyme polymorphism.     

Genetic and clonal diversity of two cattail species, Typha latifolia and T. angustifolia (Typhaceae), from Ukraine

Genetic and clonal diversity vary between two closely related cattail species (Typha angustifolia and T. latifolia) from Ukraine. This diversity was calculated from microsatellite data. Forty-eight percent of the total variation was partitioned between species, which formed distinct clusters in a dendrogram with no indication of hybrid populations. Typha angustifolia had higher heterozygosity at the species (H(es) = 0.66) and population (H(ep) = 0.49) levels than did T. latifolia (H(es) = 0.37 and H(ep) = 0.29, respectively). The higher number of alleles in T. angustifolia may be indicative of larger effective population sizes due to its higher seed production. Clonal diversity of T. angustifolia was lower than that of T. latifolia (N(g)/N(r) = 0.40 and 0.61, Simpson's D = 0.82 and 0.94, respectively). Correlations between clonal and genetic diversity were higher for T. latifolia than T. angustifolia, suggesting that the importance of factors and their interactions affecting this relationship are different for the two species. Latitudinal and longitudinal trends were not observed in either species despite the large sampling area. Population differentiation was relatively high with F(ST) of 0.24 and 0.29 for T. angustifolia and T. latifolia, respectively. Weak isolation by distance was observed for T. latifolia but not for T. angustifolia.     

The effect of geographic range and dichogamy on genetic variability and population genetic structure in Tricyrtis section Flavae

Populations of each of the four species of Tricyrtis sect. Flavae were sampled using enzyme electrophoresis to examine the effect of geographic range and dichogamy on the genetic diversity of the species. The most widespread species, T. nana, had the lowest level of genetic diversity at both the population and the species level. The depauperate genetic diversity at the population level of T. nana appears to result from the high self-fertilization of the species. The low genetic diversity at the species level of T. nana probably resulted from the bottleneck effect during the speciation process in which this species diverged from the progenitor species, T. flava. Genetic differentiation among populations was high in both adichogamous T. nana and protandrous T. flava. High self-fertilization in T. nana and the colonizing nature of T. flava are likely the main factors causing the differentiated population genetic structure. In contrast to a previous study on chloroplast DNA (cpDNA) variation in Tricyrtis sect. Flavae, T. nana was most closely related to T. flava, which corresponds to the morphological resemblance of both species.     

Qualitative and quantitative analyses of flower scent in Silene latifolia

The quantitative and qualitative variability in floral scent of 98 specimens of the dioecious species Silene latifolia belonging to 15 European and 19 North American populations was determined. Floral scent was collected from single flowers using dynamic headspace methods, and analysed by Micro-SPE and GC-MS methods. The flowers showed a nocturnal rhythm, and scent was emitted only at night. The amount of emitted volatiles varied greatly during the season, from 400 ng/flower/2 min in June to 50 ng/flower/2 min in August and September. The qualitative variability in the floral scent was high and different chemotypes, characterised by specific scent compounds, were found. Female and male flowers emitted the same type and amount of volatiles. The differences in floral scent composition between European and North American populations were small. Typical compounds were isoprenoids like lilac aldehyde isomers, or trans-beta-ocimene, and benzenoids like benzaldehyde, phenyl acetaldehyde, or veratrole. Some of these compounds are known to attract nocturnal Lepidoptera species. The high qualitative variability is discussed in relation to the pollination biology of S. latifolia, and the results are compared with other studies investigating intraspecific variability of flower scent.     

Community-dependent foraging habits of flower visitors: cascading indirect interactions among five bumble bee species

Despite the ubiquity and the importance of interspecific interactions among flower visitors, few studies have examined their effects on the realized feeding niches of visitor species in a community context. To evaluate the community-wide effects of interactions among flower visitors, I have examined changes in the flower utilization patterns of each visitor species at several sites where the component of the visitor’s community differed. Specifically, I compared the flower preferences and foraging habits (legitimate foraging vs. primary nectar robbing vs. secondary nectar robbing) of five bumble bee species in flower patches consisting of Trifolium pratense L. (red clover) and T. repens L. (white clover) on Hokkaido Island, Japan. I also examined the nectar production and standing crops of each flower species to evaluate the exploitation competition based on nectar. The bumble bee species exhibited different flower utilization patterns among sites. At sites where the long-tongued Bombus diversus tersatus was common and the exotic short-tongued B. terrestris was rare, B. diversus tersatus visited red clover (long-tubed flowers) exclusively, whereas medium-tongued B. pseudobaicalensis and short-tongued B. hypocrita sapporoensis and B. hypnorum koropokkrus preferentially visited white clover (short-tubed flowers). Conversely, at sites where the long-tongued bee was rare, four other species frequently visited red clover in different modes: B. pseudobaicalensis visited legitimately, B. hypocrita sapporoensis and B. terrestris visited as primary nectar robbers, and B. hypnorum koropokkrus visited as a secondary nectar robber. The presence or absence of resource exploitation by the long-tongued species and the interaction between primary and secondary nectar robbers via robbing holes was the major ecological sources of these differences. Diverse effects of interactions among flower visitors played important roles in shaping pattern of plant and flower visitor interactions.     

Temporal changes in calyx tube length of Clematis stans (Ranunculaceae): a strategy for pollination by two bumble bee species with different proboscis lengths

We examined the adaptive significance of a temporal decrease in the calyx tube length of Clematis stans, a dioecious species pollinated by Bombus diversus (long proboscis) and B. honshuensis (short proboscis). We compared visitation frequency, pollen removal, pollen deposition, and fruit set after a single visit among three flower stages, differentiated by calyx tube length. Bombus diversus frequently visited and removed significantly more pollen from long flowers. Bombus honshuensis visited and tended to remove more pollen from short flowers. Both pollinators deposited more pollen in short flowers, resulting in higher fruit set. These results indicate that size correspondence between the proboscis and the calyx tube enhances visitation frequency and pollen removal, but not pollen deposition. Because a single visit does not fertilize all ovules of a flower, multiple visits by two bumble bee species may increase seed production and genetic diversity of offspring. By temporally changing calyx tube length, C. stans can use two bumble bee pollinators and maintain specialized relationships with each. This strategy may be adaptive when the pollinator fauna fluctuates, and is economical because it eliminates costs required to produce different types of flowers. This constitutes a novel pattern of temporal specialization in flower-pollinator relationships.     

Plant generalization on pollinators: species property or local phenomenon?

Despite recent increased interest in the frequency and evolutionary consequences of generalization in plant-pollinator systems, little is known on whether plant generalization on pollinators actually is a species-level trait. This paper addresses the following questions for the insect-pollinated shrub Lavandula latifolia: (1) Are different populations of this pollinator-generalist plant similarly generalized? (2) Within a highly generalized population, are all plants similarly pollinator-generalists? Comparable values for richness in pollinator species were obtained from individual- or population-specific rarefaction curves as the projected number of distinct pollinator species implicated in 100 flower visits (S(RAR100)). Simple counts of pollinator species recorded per individual or population (S(OBS)) were weakly or nonsignificantly correlated with corresponding S(RAR100) figures and closely correlated with flower visitation frequency. The pollination system of L. latifolia was highly generalized at the regional level, but populations differed greatly in pollinator species richness (S(RAR100)). Within the population intensively studied, individual plants had quite variable degrees of generalization, comparable in magnitude to variation among populations. It is concluded that generalization was not an invariant, species-level property in L. latifolia. Furthermore, pollinator diversity estimates based on S(OBS) data may be heavily contingent on aspects related to both research design (sampling effort) and biological phenomena (variation in pollinator abundance or visitation rates), which may either mask or distort underlying ecological patterns of interest.     

A comparative floral and pollination biology ofTricyrtis flava maxim.,T. nana yatabe andT. ohsumiensis

The floral and pollination biology of three closely related species,Tricyrtis flava, T. nana andT. ohsumiensis, were comparatively investigated. The primary pollinator wasBombus diversus in all the three species observed, andAmegilla sp. also acted forT. ohsumiensis. The flowers ofT. flava andT. ohsumiensis bloom for two days and are protandrous. Thus autogramy seems to be prevented in these species when the larger bees forage on them, though geitonogamy may also occur. On the other hand,T. nana appears to be a primarily self-pollinating species. The flowers of this species open only during one day and are homogamy. The stigmata seem to receive much pollen of their own flower by the visit of bumblebees. Moreover, many flowers ofT. nana fruited without any visit of pollinators.T. nana has many features characterizing the autogamous derivatives.     

Sex Determination by Sex Chromosomes in Dioecious Plants

Abstract: Sex chromosomes have been reported in several dioecious plants. The most general system of sex determination with sex chromosomes is the XY system, in which males are the heterogametic sex and females are homogametic. Genetic systems in sex determination are divided into two classes including an X chromosome counting system and an active Y chromosome system. Dioecious plants have unisexual flowers, which have stamens or pistils. The development of unisexual flowers is caused by the suppression of opposite sex primordia. The expression of floral organ identity genes is different between male and female flower primordia. However, these floral organ identity genes show no evidence of sex chromosome linkage. The Y chromosome of Rumex acetosa contains Y chromosome-specific repetitive sequences, whereas the Y chromosome of Silene latifolia has not accumulated chromosome-specific repetitive sequences. The different degree of Y chromosome degeneration may reflect on evolutionary time since the origination of dioecy. The Y chromosome of S. latifolia functions in suppression of female development and initiation and completion of anther development. Analyses of mutants suggested that female suppressor and stamen promoter genes are localized on the Y chromosome. Recently, some sex chromosome-linked genes were isolated from flower buds of S. latifolia.     

'Junk' DNA and phenotypic evolution in Silene section Siphonomorpha.

One of the long-standing mysteries in genomic evolution is the observation that much of the genome is composed of repetitive DNA, resulting in inter- and intraspecific variation in nuclear DNA content. Our discovery of a negative correlation between nuclear DNA content and flower size in Silene latifolia has been supported by our subsequent investigation of changes in DNA content as a correlated response to selection on flower size. Moreover, we have observed a similar trend across a range of related dioecious species in Silene sect. Elisanthe. Given the presence of sex chromosomes in dioecious Silene species, and the tendency of sex chromosomes to accumulate repetitive DNA, it seems plausible that dioecious species undergo genomic evolution in ways that differ from what one might expect in hermaphroditic species. Specifically, we query whether the observed relationship between nuclear DNA content and flower size observed in dioecious Silene is a peculiarity of sex chromosome evolution. In the present study we investigated nuclear DNA content and flower size variation in hermaphroditic species of Silene sect. Siphonomorpha, as close relatives of the dioecious species studied previously. Although the nuclear DNA contents of these species were lower than those for species in sect. Elisanthe, there was still significant intra- as well as interspecific variation in nuclear DNA content. Flower size variation was found among species of sect. Siphonomorpha for petal claw and petal limb lengths, but not for calyx diameter. This last trait varies extensively in sect. Elisanthe, in part due to sex-specific selection. A negative correlation with nuclear DNA content was found across populations for petal limb length, but not for other floral dimensions. We conclude that impacts of nuclear DNA content on phenotypic evolution do manifest themselves in hermaphroditic species, so that the effects observed in sect. Elisanthe, and particularly in S. latifolia, while perhaps amplified by the genomic impacts of sex chromosomes, are not limited to dioecious taxa.     

Andromonoecy and fruit set in three genera of the Proteaceae

It has been suggested by some authors that the low fruit to flower ratio in some Proteaceae is due to andromonoecy, while others, looking particularly at Banksia , have not been able to find evidence for male flowers in the inflorescences. Stirlingia latifolia, Xylomelum occidentals and X. angustifolium are clearly andromonoecous, while no evidence for this condition could be found in Brabejum stellatifoliutn. Production of fertile fruit is related to andromonoecy in Xylomelum and S. latifolia but not in Brabejum. It is unlikely that all-encompassing solutions will be found to what initially seem to be widespread traits in the family, especially in regard to pollination biology, as the genera in the family occupy widely different environments and have very diverse ecological ranges.     

846. TRICYRTIS MACRANTHA

Tricyrtis macrantha Maxim. (Liliaceae), an endemic species to Japan, is illustrated. It is distributed in a small area in Shikoku (Kochi Prefecture), and grows on limestone cliffs. Tricyrtis macrantha and its allied species, T. macranthopsis Masam., distributed in Kii Peninsula in western Honshu, and T. ishiiana (Kitag. & T. Koyama) Ohwi & Okuyama, distributed in Pacific coast side of central Honshu, comprise one natural group.     

Typha×glauca Godr.,香蒲属(香蒲科)中国新记录杂种及其形态特征

香蒲属(Typha L.)为多年生水生或沼生草本植物, 种间存在十分普遍的杂交现象, 其中一些杂种在湿地生态系统中有重要的作用。在查阅大量腊叶标本基础上, 结合野外居群生物学工作, 作者发现中国一新记录杂种, 即T.×glauca Godr. (T. angustifolia L.×T. latifolia L.), 并新拟“粉绿香蒲”作该杂种的中文名。对粉绿香蒲的形态特征进行了研究, 讨论了其与亲本水烛和宽叶香蒲的区别, 并给出检索表。     

阔叶杨桐的花器官发生(山茶科)

利用扫描电镜首次观察了山茶科厚皮香亚科植物阔叶杨桐的花器官发生过程。阔叶杨桐的花被片和五束雄蕊都是2/5螺旋向心发生,且有逆时针和顺时针两种螺旋方式;五束雄蕊在环形雄蕊原基上产生,且每一束都是由中间向两端发生;由五心皮形成的中轴胎座内出现一衍生的可育胎座。阔叶杨桐的花器官发生过程与本亚科的猪血木明显不同,该研究为厚皮香亚科乃至山茶科的系统发育与演化提供花器官方面的依据。     

Differential infectivity of Transversotrema patialense for naive fish

The discovery of Transversotrema patialense cercariae in an aquarium harboring tropical fish triggered the present study. The purpose was to estimate the potential range of infection of local freshwater and fishpond populations by T. patialense. Experimental infection of T. patialense differed among 3 species employed: 76.5% for Tilapia zillii, 37.8% for Gambusia affinis, and none for 2 varieties of Cyprinus carpio. These patterns of infectivity are different from those published previously for T. patialense infections, and they may be attributed to the origin of the fish (temperate water vs. tropical and subtropical waters) and the size of their scales. In G. affinis, but not in the other species, worm load and fish length were closely related, and the left side harbored heavier worm burdens than the right side. Taken together, these results suggest that imported T. patialense may spread to various indigenous natural and cultured fish populations, with ensuing potential harm to these populations.     

Genome size, quantitative genetics and the genomic basis for flower size evolution in Silene latifolia

BACKGROUND AND AIMS: The overall goal of this paper is to construct an overview of the genetic basis for flower size evolution in Silene latifolia. It aims to examine the relationship between the molecular bases for flower size and the underlying assumption of quantitative genetics theory that quantitative variation is ultimately due to the impact of a number of structural genes. SCOPE: Previous work is reviewed on the quantitative genetics and potential for response to selection on flower size, and the relationship between flower size and nuclear DNA content in S. latifolia. These earlier findings provide a framework within which to consider more recent analyses of a joint quantitative trait loci (QTL) analysis of flower size and DNA content in this species. KEY RESULTS: Flower size is a character that fits the classical quantitative genetics model of inheritance very nicely. However, an earlier finding that flower size is correlated with nuclear DNA content suggested that quantitative aspects of genome composition rather than allelic substitution at structural loci might play a major role in the evolution of flower size. The present results reported here show that QTL for flower size are correlated with QTL for DNA content, further corroborating an earlier result and providing additional support for the conclusion that localized variations in DNA content underlie evolutionary changes in flower size. CONCLUSIONS: The search image for QTL should be broadened to include overall aspects of genome regulation. As we prepare to enter the much-heralded post-genomic era, we also need to revisit our overall models of the relationship between genotype and phenotype to encompass aspects of genome structure and composition beyond structural genes.     

Pollinator responses to variation in floral display and flower size in dioecious Sagittaria latifolia (Alismataceae)

In animal-pollinated plants with unisexual flowers, sexual dimorphism in floral traits may be the consequence of pollinator-mediated selection. Experimental investigations of the effects of variation in flower size and floral display on pollinator visitation can provide insights into the evolution of floral dimorphism in dioecious plants. Here, we investigated pollinator responses to experimental arrays of dioecious Sagittaria latifolia in which we manipulated floral display and flower size. We also examined whether there were changes in pollinator visitation with increasing dimorphism in flower size. In S. latifolia, males have larger flowers and smaller floral displays than females. Visitation by pollinators, mainly flies and bees, was more frequent for male than for female inflorescences and increased with increasing flower size, regardless of sex. The number of insect visits per flower decreased with increasing floral display in males but remained constant in females. Greater sexual dimorphism in flower size increased visits to male inflorescences but had no influence on the number of visits to female inflorescences. These results suggest that larger flower sizes would be advantageous to both females and males, and no evidence was found that females suffer from increased flower-size dimorphism. Small daily floral displays may benefit males by allowing extended flowering periods and greater opportunities for effective pollen dispersal.     

An examination of hybridization between the cattail species typha latifolia and typha angustifolia using random amplified polymorphic DNA and chloroplast DNA markers

Typha glauca represents a significant portion of the biomass of the wetlands surrounding the Great Lakes, USA. It is generally accepted to be a form of hybrid between T. latifolia and T. angustifolia, which itself appears to be an exotic introduction from Europe. Based on morphological and isozyme data, conflicting theories have been proposed for the hybrid nature of T. glauca: it has been described as a hybrid swarm, a distinct hybrid species and an F1 hybrid. Therefore, we developed random amplified polymorphic DNA (RAPD) and chloroplast DNA markers, specific to the parental species, to assess hybrids. Ten RAPD primers gave 17 fragments specific to T. angustifolia and 13 fragments specific to T. latifolia. All of the interspecific hybrids contained each of the species-specific markers, indicating an F1 hybrid status. Furthermore, all hybrids tested contained the T. angustifolia chloroplast haplotype, which is consistent with differential interspecific crossing success found previously. Additional confirmation of an F1 hybrid status was gained by examining seedlings from T. glauca. These progeny were expected to be advanced-generation hybrids, as opposed to the F1 hybrid parent. Analysis of the seedlings revealed segregating marker patterns consistent with patterns observed in experimental advanced-generation hybrids, although these advanced hybrids do not appear to be a significant part of mature stands. Our data do not provide support for extensive gene flow between T. latifolia and T. angustifolia. However, our results suggest that hybridization between the native and introduced Typha species has impacted the native population through the spread of the F1 hybrid, T. glauca.     

菰属Zizania L.植物的分支分类研究

本文应用分支分类学中的最大同步法对全世界菰属Zizania L.及其有关属种进行定量分析研究其种系发生后所得出的分支树谱图上明显表示出法洛斯属Pharus Br.不应该与菰属、稻属Oryza L.等同位在稻族Oryzeae内,而应另立法洛斯族Phareae.菰属在稻族中独立出较进化的一支,当今称为菰亚族Zizaniinae.在菰属内全世界有4种.2亚种,其演化关系为菰Z.latifolia是最原始,由它分别向得克萨斯菰Z.texana及水生菰Z.aquatica演化,再由水生菰演化至沼生菰Z.palustris。