Corydalis hirtipes B.U. Oh et J.G. Kim: A new species ofCorydalis sectCorydalis (Fumariaceae) from Korea

Here we describe a new species ofCorydalis sectCorydalis (Fumariaceae), namely C.hirtipes B.U. Oh et J.G. Kim. This species, from the central part of Korea, is clearly distinguished from other species of sectCorydalis by its simple, unicellular hairs that are densely distributed on the stems, peduncles, and petioles. It is also distinctive from its close relative C.albipetala in having ternate leaves, lobate or parted leaflets, dentate or cleft bracts, and broad, fusiform fruits.     

紫堇科二新种

该文描述了紫堇科二新种:(1)自云南省发现的紫堇科紫堇属一新种,宽鳞紫堇。此新种与波密紫堇相近似,与后者的区别在于本新种的根状茎鳞片半透明,具三条脉,茎无叶,外花瓣无鸡冠状突起,雄蕊束具2花药,花丝条形,无脉,子房宽条形。(2)自黑龙江省发现的紫堇科紫堇属一新种,鹤岗延胡索。此种与新疆元胡相似,但本种叶的小叶多在顶端,具1~5牙齿,花序苞片有3~5小裂片,上花瓣及其瓣片和距均较小,蜜腺呈狭卵球形,弯曲,顶端尖锐而与新疆元胡相区别。     

鹤岗延胡索, 黑龙江紫堇科一新种

描写了自黑龙江省发现的紫堇科紫堇属一新种,鹤岗延胡索。此种与新疆元胡相似,但本种叶的小叶多在顶端具1～5牙齿,花序苞片有3～5小裂片,上花瓣及其辦片和距均较小,蜜腺呈狭卵球形,弯曲,顶端尖锐而与新疆元胡相区别。     

Beyond pollen:ovule ratios: Evolutionary consequences of pollinator dependence and pollination efficiency for pollen and ovule production in angiosperms

Premise

The relative per-flower production of ovules and pollen varies broadly with angiosperm mating systems, with outcrossing types commonly producing more pollen grains per ovule than selfing types. The evolutionary causes of this variation are contentious, especially the relevance of pollination risk. Resolution of this debate may have been hampered by its focus on pollen:ovule (P:O) ratios rather than on the evolution of pollen and ovule numbers per se.

Methods

Using published mean ovule and pollen counts, we analyzed associations with the proportion of removed pollen that reaches stigmas (pollen-transfer efficiency) and differences between pollinator-dependent and autogamous forms within and among species. Analyses involved Bayesian methods that simultaneously considered variation in pollen and ovule numbers and accounted for phylogenetic relatedness. We also assessed the utility of P:O ratios as mating-system proxies and their association with female outcrossing rates.

Results

Median pollen number declined consistently with pollen-transfer efficiency among species, whereas median ovule number did not. Similarly, in both intraspecific and interspecific analyses, pollinator-dependent plants produced more pollen than autogamous plants, whereas ovule production did not differ statistically. Distributions of P:O ratios overlapped extensively for self-incompatible and self-compatible species and for different mating-system classes, and P:O ratios correlated weakly with outcrossing rate.

Conclusions

Our findings demonstrate that pollinator dependence and pollination efficiency commonly influence the evolution of pollen number per flower but have more limited effects on ovule number. P:O ratios provide ambiguous, possibly misleading, information about mating systems, especially when compared among clades.

     

The relative importance of architecture and resource competition in allocation to pollen and ovule number within inflorescences of Hosta ventricosa varies with the resource pools

Background and Aims

Allocation of resources to floral traits often declines distally within inflorescences in flowering plants. Architecture and resource competition have been proposed as underlying mechanisms. The aim of the present study is to assess the relative importance of resource competition and architectural effects in pollen and ovule production on racemes of Hosta ventricosa, an apomictic perennial herb.

Methods

Combinations of two defoliation treatments (intact and defoliated) and two fruit-set treatments (no-fruit and fruit) were created, and the roles of architecture and resource competition at each resource level were assessed.

Key Results

Pollen and ovule number per flower increased after defoliation, but pollen to ovule ratio per flower did not change. Pollen, ovules and the pollen to ovule ratio per flower declined distally on racemes at each resource level. In the intact treatment, fruit development of early flowers did not affect either pollen or ovule number of late flowers. In the defoliated treatment, fruit development of early flowers reduced both pollen and ovule numbers of late flowers due to over-compensation caused by defoliation. Late flowers on defoliated fruit racemes produced less pollen than intact fruit racemes but the same number of ovules; therefore, the reduction in pollen number was not caused by over-compensation. In addition, the fruit-set rate of early flowers during flowering was higher in intact racemes than in defoliated racemes.

Conclusions

In flowering plants, the relative importance of architecture and resource competition in allocation to pollen and ovules may vary with the resource pools or the overall resource availability of maternal plants.     

Seed-coat anatomy of japanese species ofCorydalis andDicentra (Papaveraceae; Fumarioideae)

Development and structure of seed-coat were examined in 16 species ofCorydalis and two species ofDicentra. Neither the tegmen (developed ii) nor the testa (developed oi) is multiplicative during seed development. Mature seed-coat is consistent in all the species examined in having mechanical structure in the exo- or endotesta. Differences are found in (1) which of the integumentary layers develops into the main mechanical layer (exotesta or endotesta), (2) whether a mesotesta is differentiated or not, and (3) whether the endotegmen is persistent as a layer of thick-walled cells, is persistent only partially, or is thoroughly degenerated. Theses seed-coat characters distinguish six groups of species (i.e., four groups inCorydalis and two inDicentra), which represent well infrageneric taxa proposed on the other characters. Evidence from seed-coat anatomy further suggests thatDicentra spectabilis (subg.Hedycapnos) retains the primitive (endotestal) seed-coat of Fumarioideae.     

Pollen size-number trade-off and pollen-pistil relationships in Pedicularis (Orobanchaceae)

Current patterns of floral design in Pedicularis must have undergone an evolutionary process of interacting among components of floral traits, and then formed internal relationships among these traits. To detect such correlations, which may provide insight to understand flower evolution, 40 Pedicularis species representing all corolla types of the genus were studied. Results show that, interspecifically, pollen size correlates negatively with pollen number, but positively with pistil length. This suggests that plants evolve an optimal pollen size, which balances the advantages of large pollen size for gametophytic competition against the fecundity disadvantages of fewer pollen grains. In contrast to sex allocation theory, this study does not find a trade-off, but an interspecific positive correlation between pollen and ovule number. This is consistent with the hypothesis that genetic variation for resource acquisition may in part be responsible for the lack of negative correlation between male and female function.This work was supported by the State Key Basic Research and Development Plan, China (Grant No. G2000046804) to YHG. The authors would like to thank Peter K. Endress and two anonymous reviewers for providing critical comments and helpful suggestions, Qing-Feng Wang, Jing-Yuan Wang and Jin-Ming Chen for their helpful suggestions. Shi-Guo Sun, Jing Xia, and Qian Yu are thanked for their assistance in both the field work and laboratory phases of the project.     

Pollen-Ovule Ratio and Gamete Investment in Pedicularis （Orobanchaceae）

The Pedicularis species provides ideal materials to study floral evolution because of their substantial flower variation based on a narrow genetic basis, even though they are almost exclusively pollinated by bumblebee. These traits allow us to detect the evolutionary trends of floral parameters without considering genetic background and the difference of pollination vectors. The pollen-ovule ratio is widely used to estimate the pattern of resource investment in two sexual functions in flowering plants. Forty species representing all of the corolla types in Pedicularls were used to study pollen-ovule ratio, gamete investment, and their correlations. Results show that pollen-ovule ratio does not differ among both different corolla types and taxonomic groups. It is therefore suggested that pollen-ovule ratio should be a parallel evolution. The correlations between pollen-ovule ratio and pollen size （-）, and ovule size （＋） can be successfully explained in terms of sex allocation theory. The biological significance of such relationships was also discussed. Additionally, we analyzed the pattern of resource investment into female gamete, which has been somewhat neglected, and found that plants have different patterns of gamete investment between the two sexual functions.     

Infrageneric variability of pollen morphology in Palaua (Malveae,Malvaceae) and the taxonomic utility of quantitative pollen characters

Palaua (Malvaceae) comprises 15 species endemic to the coastal deserts of Chile and Peru. Previous molecular phylogenetic analyses have shown that this genus is monophyletic and can be subdivided into three clades. In the present study, pollen morphology of all species of Palaua was examined using light and scanning electron microscopy to determine whether it provides additional data in support of the proposed infrageneric groups. The pollen grains are spheroidal, medium to large in diameter, spinose and pantocolporate – the ectocolpi are very short. The tectum is perforate and characterised by granula. In all species the nexine is of a similar thickness in all areas of the pollen grain, while the sexine thickness varies, being notably thicker in the areas where the broad spine bases are sited (‘spine cushions’). Many of the quantitative characters have conspicuous variability, but the variability shows considerable overlap between species. Nonetheless, P. guentheri, P. inconspicua, P. malvifolia and P. modesta are united as a group by having the smallest pollen grains with the smallest apertures, the shortest spines and the shortest interspinal distance. This grouping reflects only partially the suggested infrageneric clades, although it does tend to unite the species with the smallest flowers. A possible link between reproductive resources and pollen size is also considered, as well as the influence of polyploidy. However, the taxonomic utility of these quantitative characters is weakened by species with more than one cytotype.     

Variation in structural gender in the hermaphrodite Helleborus foetidus (Ranunculaceae): within- and among-population patterns

In hermaphrodite plants, variations in structural gender (defined as the ratio between male and female gametes) may occur at different levels (among flowers, plants, and populations). In this study, we investigated variation in four traits influencing structural gender (number of carpels, ovules per carpel, stamens, and pollen grains per stamen) within and among six distant populations of the hermaphrodite perennial herb Helleborus foetidus (Ranunculaceae) in the Iberian Peninsula. Our results show that the four traits investigated varied significantly at all levels considered. Traits influencing the female sexual component (number of carpels and ovules per carpel) showed greater variation at the lowermost levels (within flower and plant) than traits influencing the male component, which in turn varied more markedly among populations. Number of carpels per flower and number of pollen grains per anther were the most important traits affecting between-plant variation in structural gender. There was no evidence of significant plant-level trade-offs or correlations between the various male and female traits, which covaried differently across populations. The observed between-population variation in structural gender of Helleborus foetidus can be explained as a consequence of differences in self-pollination levels related to a flowers mating environment.     

Temporal variation in the pollen:ovule ratios of Clarkia (Onagraceae) taxa with contrasting mating systems: field populations

Among plants, pairs of selfing vs. outcrossing sister taxa provide interesting systems in which to test predictions concerning the magnitude and direction of temporal changes in sex allocation. Although resource availability typically declines towards the end of the growing season for annual taxa, temporal changes in mating opportunities depend on mating system and should change less in selfing taxa. Consequently, given that the pollen:ovule (P:O) ratio of flowers reflects the investment in (and potential fitness pay-off due to) male vs. female function, we predicted that the P:O ratio should also be less variable among and within selfers than in closely related outcrossers. To test these predictions, we measured temporal changes in sex allocation in multiple field populations of two pairs of sister taxa in the annual flowering plant genus Clarkia (Onagraceae). In the outcrossing Clarkia unguiculata and the selfing Clarkia exilis, ovule production declined similarly from early to late buds, whereas pollen production remained constant or increased in the outcrosser but remained constant or decreased in the selfer. Consequently, the P:O ratio increased within unguiculata populations but marginally increased or stayed constant in exilis populations. In all populations of the selfing Clarkia xantiana spp. parviflora and the outcrossing C. x. spp. xantiana, both ovule and pollen production per flower declined over time. The effects of these declines on the P:O ratio, however, differed between subspecies. In each xantiana population, the mean P:O ratio did not differ between early and late flowers, although individuals varied greatly in the direction and magnitude of phenotypic change. By contrast, parviflora populations differed in the mean direction of temporal change in the P:O ratio. We found little evidence to support our initial predictions that the P:O ratio of the selfing taxa will consistently vary less than in outcrossing taxa.     

Factors affecting intrafruit pattern of ovule abortion and seed production in Hormathophylla spinosa (Cruciferae)

We investigated the pattern of intrafruit seed production in Hormathophylla spinosa (Cruciferae) over a 7-yr period. H. spinosa fruit have two chambers, each chamber containing two ovules, and usually situate perpendicular to the infructescence axis with one chamber above the other. The percentage of ovules ripening to seeds is usually lower than 50%. In addition, we found a consistent position-dependence in seed ripening probability, since more than 90% of the ripe seeds are arranged in the lower chamber of the fruit. This pattern of seed production is not produced by the direct or indirect effect of seed predators, by pollen limitation or by nonrandom fertilizations. By contrast, fruit removal experiments showed that sibling rivalry can partially explain the seed production pattern, be the cause of the reduction in the seed number from the uppermost threshold of 50%. Moreover, experimental manipulations of fruit orientation suggest that the position-dependence in seed production is the cause but not the effect of seed ripening. We presume that some architectural effect is producing a significant increase in the ripening probability of the ovules arranged in the lower chamber, causing thus the observed pattern in the intrafruit seed production in H. spinosa and severely constraining the maximum number of seeds per fruit to two.     

Variation and geographical distribution of ploidy levels inPennisetum sectionBrevivalvula (Poaceae) in Burkina Faso,Benin and southern Niger

Pennisetum sect.Brevivalvula is a species complex characterized by polyploidy and apomixis. Ploidy level was assessed by DAPI-flow cytometry for 304 plants of the section, originating from Burkina Faso, Benin and southern Niger. The results were confirmed for 54 plants based on chromosome counts. The samples show four euploidy levels (with x = 9) distributed among five species:P. hordeoides (2n = 36, 54),P. pedicellatum (2n = 36, 45, 54),P. polystachion (2n = 18, 36, 45, 54),P. setosum (2n = 54), andP. subangustum (2n = 18, 36, 54). The geographical distribution of these ploidy levels seems related to major vegetation zones present in Africa. Diploid populations ofP. polystachion andP. subangustum were found in the Banfora area, in Burkina Faso.     

云南草寇花序内不同部位的性分配

两性花植物花序内的性分配常存在差异,资源竞争、结构效应、交配环境(雌雄异熟、传粉者定向访花行为等)或授粉不均匀等几种假说可以解释这种现象。为验证上述假说,该研究以云南草寇两种表型(雄先熟型和雌先熟型)为材料,分析了其花序内不同部位(基部、中部和顶部)的每花花粉数、胚珠数、花粉/胚珠比、结实率和结籽率,花序内传粉者的定向访花行为,以及人工辅助授粉和去花处理对结实率和结籽率的影响。结果表明:两种表型花序内每花花粉数不随部位而变化,每花胚珠数、结实率和结籽率由基部到顶部依次降低,每花花粉/胚珠比由基部到顶部依次增加,表明顶部花存在偏雄的性分配。人工辅助授粉后,结实率、结籽率仍由基部到顶部依次降低,表明授粉不均匀假说不能解释云南草寇花序内不同部位结实率、结籽率的差异。去除基部和中部花后,顶部花人工辅助授粉条件下的结实率、结籽率与基部花人工辅助授粉条件下的结实率、结籽率无差异,表明云南草寇花序内不同部位结实率、结籽率的差异主要由资源竞争引起。雌先熟表型每花花粉数、花粉/胚珠比高于雄先熟表型,表明两种表型存在性分配差异。传粉者主要先访问云南草寇基部的花,然后向顶部移动。云南草寇花序内顶部偏雄的性分配可能是由资源竞争和传粉者定向访花造成的。     

Contribution to the taxonomy and phylogeny of Sarcocapnos DC. (Fumariaceae)

 To solve problems concerning the status of the taxa described in the genus Sarcocapnos, we have conducted a study using morphological, pollen morphology (light microscopy), cytogenetic and molecular techniques. Focusing on the last technique, we have sequenced ITS-1 and ITS-2 of nuclear rDNA. The species differ basically according to 5 morphological traits (leaf shape, flower spur, corolla colour, corolla size, and crest of the stigmatic surface). The cytogenetic analyses indicated n=16 to be the standard chromosome number. The ITS analyses showed that the genus is monophyletic, defining two main well-supported clades, one containing S. saetabensis and S. enneaphylla, and one containing the rest of the species. In this second clade, S. speciosa, S. pulcherrima, and S. baetica subsp. ardalii are related, as are S. integrifolia, S. crassifolia subsp. crassifolia, and S. crassifolia subsp. atlantis; S. baetica subsp. baetica forms a trichotomy with the foregoing groups. S. speciosa is shown to be a species separate from S. crassifolia subsp. crassifolia, as in the case of S. baetica with respect to S. integrifolia. Palynologically, the parameters used enabled us to establish clear differences between the taxa, often corroborating the macromorphological and genetic data. The flower spur has been reduced several times in different groups of the genus, for which the classifications established on the basis of this trait are paraphyletic. Received July 16, 2002; accepted December 11, 2002 Published online: March 31, 2003     

A phenetic comparison of someFumaria spp. (Fumariaceae)

The taxonomy of the genusFumaria has not been considered in detail sincePugsley's work in 1919 ff., and few modern methods have been applied to it. In a phenetic study, 33 populations of 11Fumaria spp. were grown in uniform conditions, and seven morphological characters measured. After re-expression and transformation the data were analysed by cluster analysis and principal components analysis. Alternative analyses did not indicate contradictory taxonomic conclusions. Artificial crosses gave some evidence on interfertility, and suggestedF. occidentalis to be an allopolyploid ofF. bastardii ×F. capreolata. Pugsley's subsectional classification is supported within sect.Parviflora, but not within sect.Grandiflora. His two sections are seen to be meaningful, but not discrete.     

The size and germinability of Scots pine pollen in different temperatures in vitro

The effect of genotype, the origin of genotype, and germination temperature on Scots pine pollen grain size, hydration rate, germinability, and tube growth was studied in vitro. The mean sizes of dry and germinated pollen grains varied among pollen genotypes in different ways, thus the hydration rate varied among genotypes. Pollen from Scots pine that originates in northern Finland hydrated more than pollen from a population in southern Finland. Germination temperature had no effect on the hydration rate. Germinability and tube growth rate of northern genotypes were higher at 20 °C than at 15 °C. Differences among southern genotypes were not significant. At 15 °C, the germinability and pollen tube growth rate of northern genotypes were lower than southern genotypes. At 20 °C, the differences were not significant. It appears that germination and growth of pollen from northern populations are enhanced at higher temperatures whereas pollen from southern populations is unaffected.     

Natural levels of pollination intensity and effects of pollen loads on offspring quality in females of Thalictrum pubescens (Ranunculaceae)

Females of Thalictrum pubescens produce stamens containing sterile pollen. Earlier studies have shown the presence of stamens does not increase seed set through increased visitation by insects. Insects may, however, increase pollen deposition on stigmas and increase pollen competition. This paper examines: 1) pollen deposition levels in natural populations and 2) whether larger pollen loads lead to higher quality offspring. The majority of stigmas in two populations received less than 15 grains, but a small proportion had large loads. The latter may represent the occasional insect visit. These visits may provide the opportunity for pollen tube competition. In the greenhouse, flowers receiving heavy-pollen loads had higher seed set than flowers receiving light-pollen loads. Seeds from the two treatments were the same mass, had similar germination times, and seedlings had the same mass. In conclusion, it does not appear that pollen tube competition can account for the maintenance of stamens in females of T. pubescens.