草乌传粉过程中的广告效应与回报物质研究

虫媒传粉植物与其传粉者之间的相互作用被认为是被子植物花多样性的一个重要选择压力。这种相互作用体现在植物对传粉者的吸引以及传粉者行为对花粉的转运两个方面。本项研究通过去除不同的花部器官研究了草乌(Aconitum kusnezoffii)对其传粉者的吸引, 并结合传粉者的访问行为和草乌花的生物学特性探讨了传粉过程与交配系统的适应。红光熊蜂(Bombus ignites)是草乌的有效传粉者。去除花萼片显著降低了红光熊蜂的访问频率, 但去除特化成蜜腺叶的花瓣并没有显著改变红光熊蜂的访问频率, 这表明草乌吸引红光熊蜂的主要结构是由5枚萼片组成的花部外观形态, 而非花瓣。花蜜是草乌提供给红光熊蜂的回报物质, 糖浓度为39.23%, 组氨酸浓度为0.25 μg/μL。草乌花较大、单花花期长、雌雄异熟、花粉寿命长, 是一个自交亲和但需传粉者传粉完成繁殖过程的异交物种。草乌花序是无限花序, 当上部的花处于雄性阶段时, 下部的花正好处于雌性阶段。而红光熊蜂在草乌花序上的访问顺序通常自下而上, 带来异交花粉为下部的花进行异花授精, 同时又带走上部花的花粉, 这就很好地促进了草乌的异交。草乌雄蕊自外向内逐渐成熟, 是一种有效的限制传粉者单次访问浪费大量花粉的花粉装配策略, 能提高植物通过花粉散布获得的雄性适合度。     

Male-biased sex allocation in late-blooming flowers driven by resource limitation in the clonal perennial Aconitum kusnezoffii (Ranunculaceae)

Flowering phenology and clonal growth are known to affect resource and pollen availability, and therefore select for adaptive or constrained sex allocation strategies to some degree. However, the consequences of temporal sex allocation patterns for reproductive fitness across the flower, inflorescence, and genet levels have rarely been examined. Moreover, experimental tests of the underlying regulatory mechanisms are scarce. We examined the association of flowering phenology and inflorescence position with temporal sex allocation and reproductive success in the protandrous perennial clonal herb, Aconitum kusnezoffii, over four consecutive growing seasons by examining more than 39 000 flowers. We also conducted controlled experiments to test the effects of resource and pollen limitation on the female reproductive success of lateral inflorescences. We found that some male functions were positively correlated with flowering phenology, whereas female reproductive success was negatively correlated with flowering phenology and inflorescence position. Lateral inflorescences invested more in male function than terminal inflorescences and therefore yielded fewer and smaller seeds. Resource limitation may serve as the key mechanism underlying this differentiated pattern. Decreased female reproductive success was consistently observed at the flower and inflorescence levels as flowering occurred later in the growth season. Late-blooming lateral inflorescences specialized in the male function, and their female reproductive success was constrained by early-blooming terminal inflorescences. This might be the first attempt to systematically demonstrate sex allocation strategy differentiation in a protandrous plant species at the inflorescence level. In addition, our study provides empirical evidence of dichogamy selecting for specialized sex allocation strategies among inflorescences.     

Polyploidy in Aconitum subgenus Lycoctonum (Ranunculaceae)

Chromosome numbers and morphology in 22 populations belonging to 11 taxa of Aconitum subgenus Lycoctonum (Ranunculaceae) from China were studied. Some taxa were diploid, with 2 n  = 16, but four species and two varieties were found to be tetraploid, with 2 n  = 32. They are concentrated in the Hengduan Mountains region in south-west China, indicating that polyploidy could have played an important role in the speciation of the subgenus in this region, one of the areas of the world with a high concentration of endemic species. The relationships of some of the species are discussed.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 343–353.     

Seed morphology in some European aconites (Aconitum,Ranunculaceae)

The seed coat morphology, investigated in taxa representative of the main European groups ofAconitum, are in good agreement with the current taxonomy of the genus. The seed coat microcharacteristics (warty epidermal cells) are very constant. There is a trend for the reduction of longitudinal wings on the edges concomitant with the development of ridges and transverse wings on the faces. Another morphological progression leads from smooth to rugulose and eventually to transverse wing-bearing seed faces. A working hypothesis suggests an ecological adaptative significance to these changes.     

四川乌头属的修订

四川是我国乌头属Aconitum L.植物的重要分布区。本文对该地区的乌头属植物进行了分类修订。通过文献查阅、野外观察和标本室研究,对乌头属的形态性状在居群间和居群内的变异式样进行了比较分析,发现叶分裂程度、上萼片的形状和花梗毛被等性状是较为可靠的分种依据,但是在个别情况,这些性状也会在同一种的同一居群内或不同居群间发生变化。花瓣和种子的特征对于属下划分有重要意义。本文承认四川乌头属植物有46种11变种,另有2种和1变种暂存疑。29种和22变种降为异名;作出新组合2个,其中包括1个改级新组合。紫乌头A. delavayi Franch.和保山乌头A. nagarum Stapf为四川新分布记录。对康定乌头A. tatsienense Finet &; Gagnep.、川鄂乌头A. henryi Pritz.和狭裂乌头A. refractum (Finet &; Gagnep.) Hand.-Mazz.进行了后选模式的标定。初步澄清了东俄洛乌头A. tongolense Ulbr.和狭裂乌头等种类中长期存在的名实混乱。还给出了各个种的形态描述、地理分布以及分亚属、分系和分种检索表。     

Five new alkaloids from Aconitum apetalum (Ranunculaceae)

Twenty-one alkaloids, including five new ones, acoapetaldines A–E (1–5), were isolated from the whole plants of Aconitum apetalum. Among them, 1 is an aconitine-type diterpenoid alkaloid, 2 and 3 are aporphine alkaloids and 4 and 5 are napelline-type diterpenoid alkaloids. The structures of the new alkaloids were elucidated by spectroscopic data analysis and that of acoapetaldine D (4) was confirmed by single crystal X-ray crystallography. Acoapetaldine A (1) and aconorine (12) exhibited moderate anti-tobacco mosaic virus (anti-TMV) activity, while corydine (15) displayed moderate antimicrobial activity against Pseudomonas aeruginosa.     

Interpopulation variation in nectar production in Aconitum columbianum (Ranunculaceae)

Summary In Aconitum columbianum there are extreme interpopulation differences in rates of nectar secretion per flower. Since nectar sugar concentration varies little among populations, increased nectar secretion results in a greater mass of sugar per flower for pollinator attraction. These differences in the amount of reward offered per flower account at least in part for observed higher levels of pollinator activity in populations with high nectar production. Nectar production is correlated also with nectary depth, i.e., flowers in populations with deep nectaries have higher rates of nectar secretion than those with shallow nectaries. Nectary depth differences adapt populations to different pollinator-types. Populations with deeper nectaries are adapted to pollination by bumblebees with longer tongues and more specialized foraging behaviors. In conclusion, there are basic differences in pollination ecology among geographical races of a. columbianum, which are indicated by correlated interpopulution differences in (1) nectar production, (2) level of pollinator activity, (3) nectar depth, and (4) pollinator-type.     

四川乌头属二新种

描述了自四川西部发现的毛茛科乌头属二新种,细盔乌头和疏叶乌头,并给出其等与近缘种的区别特征。     

Anthocyanins and anthocyanidins in the flowers of Aconitum (Ranunculaceae)

The presence of anthocyanidins and anthocyanins were analyzed in flowers of 30 taxa of Aconitum. Delphinidin was detected as a major anthocyanidin from the hydrolysate of 29 taxa with violet and violet-blue flowers. Pelargonidin was identified as a major anthocyanidin in one taxon with white flowers (partially pale reddish purple; White group N155C by R.H.S. Colour Chart). This is the first reported detection of pelargonidin as a major anthocyanidin from Aconitum flowers. Pelargonidin was also found in ten taxa as a minor anthocyanidin, whereas cyanidin was detected from the flowers of all 30 taxa as a minor anthocyanidin.Two anthocyanins polyacylated by p-hydroxybenzoic acids, violdelphin and monodeacylcampanin were identified from 29 taxa with violet and violet-blue flowers as major anthocyanins. This is the first reported isolation of monodeacylcampanin from Aconitum flowers. The structures of these two anthocyanins were elucidated on the basis of Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS).     

Two New Species of Aconitum (Ranunculaceae) from Xizang

Two species of the genus Aconitum (Ranunculaceae), Anovoaxillare and Abasitruncatum, are described as new from Xizang Autonomous Region, China. The diagnostic differences between them and their allies are given.     

Effects of population size and isolation on reproductive output in Aquilegia canadensis (Ranunculaceae)

It is generally expected that small, isolated populations will suffer reduced fitness due to inbreeding, yet few studies have investigated the relation between population characteristics, inbreeding and fitness. Among Ontario populations of the short‐lived, perennial plant Aquilegia canadensis, large populations (N>90 flowering plants) outcross twice as frequently as small populations (N=30–40), and inbreeding depression is extremely strong. We tested the prediction that reproductive output, a major component of population fitness, should be positively associated with population size. Data from a survey of 33 populations located on small islands in the St. Lawrence River, Canada and 23 populations on adjacent mainland areas supported this prediction. Population size correlated positively with reproductive output, measured as the number of seedlings produced per plant in 1995 (average r=+0.39 pooled P=0.019), and the number of fruits per plant in 1997 (r=+0.30, P=0.056). We also tested the prediction that fitness should decline with increasing spatial isolation between populations by measuring the distance separating all island populations. However, reproductive output did not correlate with isolation in either year. We compared island and mainland populations to test the prediction that reproductive output should be lower for populations on small islands than those occurring in more continuous mainland habitat. In contrast to our predictions, island populations exhibited, if anything, higher reproductive output than mainland populations. We also found no support for the prediction that the positive association between population size and reproductive output should be stronger for presumably isolated populations on small islands than for those on adjacent mainland areas. While the mechanisms underlying the association between population size and fitness are impossible to identify with correlations alone, our results are consistent with the hypothesis that inbreeding can significantly reduce the fitness of natural populations.     

Effects of floral display size on male and female reproductive success in Mimulus ringens

Background and Aims

The number of flowers blooming simultaneously on a plant may have profound consequences for reproductive success. Large floral displays often attract more pollinator visits, increasing outcross pollen receipt. However, pollinators frequently probe more flowers in sequence on large displays, potentially increasing self-pollination and reducing pollen export per flower. To better understand how floral display size influences male and female fitness, we manipulated display phenotypes and then used paternity analysis to quantify siring success and selfing rates.

Methods

To facilitate unambiguous assignment of paternity, we established four replicate (cloned) arrays of Mimulus ringens, each consisting of genets with unique combinations of homozygous marker genotypes. In each array, we trimmed displays to two, four, eight or 16 flowers. When fruits ripened, we counted the number of seeds per fruit and assigned paternity to 1935 progeny.

Key Results

Siring success per flower declined sharply with increasing display size, while female success per flower did not vary with display. The rate of self-fertilization increased for large floral displays, but siring losses due to geitonogamous pollen discounting were much greater than siring gains through increased self-fertilization. As display size increased, each additional seed sired through geitonogamous self-pollination was associated with a loss of 9·7 seeds sired through outcrossing.

Conclusions

Although total fitness increased with floral display size, the marginal return on each additional flower declined steadily as display size increased. Therefore, a plant could maximize fitness by producing small displays over a long flowering period, rather than large displays over a brief flowering period.     

Group size,composition, and reproductive success in wild common marmosets (Callithrix jacchus)

Data from published sources about size and composition of wild common marmoset groups (Callithrix jacchus) were analyzed to see if the number of juveniles in a group is closely related to the number of other group members. Mean group size was 8.7 members including 4.4 adults (1.8 females, 2.5 males), 2.9 subadults, and 1.4 juveniles. The number of juveniles was significantly positively correlated to the number of adult males. Groups with one or two adult males had significantly fewer juveniles (mean: 1:1 juveniles) than groups containing more than two adult males (mean: 2.0 juveniles). Apart from a different number of subadults, results showed obvious similarities between common marmosets and tamarins of the genus Saguinus in size and composition of subgroups of adults as well as the key role of adult males in mediating the reproductive success of a breeding female. Common marmoset females seem to gain direct fitness benefits in increased reproductive success from the presence of a larger number of adult males. Whether or not other group members get fitness benefits depends on the reproductive strategy of adult males (monogamy vs. polyandry), their kinship, and on the genetic relationship of nonbreeders to the offspring of the breeding female. © 1995 Wiley-Liss, Inc.     

Flowering phenology,floral display and reproductive success in dioecious,Aralia nudicaulis L. (Araliaceae)

Summary Aralia nudicaulis L. is a dioecious, perennial, herbaceous plant that is commonly found in the understory vegetation throughout the boreal forest of North America. Female remets have fewer flowers per inflorescence, initiate flowering earlier, and reach peak flowering before male ramets. The consequences of the asynchrony in flowering between the sexes on pollination and seed set were examined during a two-year study. In both years there was significant variation in seed set associated with the flowering times of individual female ramets. In 1983, seed production was highest in the middle of the flowering season. In 1984, seed production was greatest in the later stages of flowering. Variation in seed set was not attributed to lack of pollination in 1983. In 1984, pollination limited seed set per flower during peak flowering. However, seed production never reached the potential five seeds per flower, suggesting that resource limitation was the most important factor affecting fecundity in both years. The asynchronous pattern of flowering is suggested to be the result of the different inflorescence sizes between the sexes.     

Male reproductive success increases with alliance size in Indo-Pacific bottlenose dolphins (Tursiops aduncus)

1. Determining the extent of variation in male mating strategies and reproductive success is necessary to understand the fitness benefits of social and cooperative behaviour. 2. This study assesses the reproductive success of male Indo-Pacific bottlenose dolphins in a small embayment population where different behavioural strategies of males have previously been identified. Parentage for 44 sampled calves was examined using 23 microsatellite loci and one mitochondrial DNA marker. Our candidate parent pool of 70 males and 64 females contained individuals sampled from both the embayment and adjacent coastal populations. 3. A moderate level of polygyny was detected in our sample. We assigned paternity of 23 calves to 12 males at the strict 95% confidence level and an additional nine calves to two males at the 80% confidence level. The majority (92%) of successful males were identified as residents to the embayment, and 46% of offspring were located within the same social group or community as their father. 4. Our results suggest that the size of alliances was the best predictor of reproductive success for males in this population, while the strength of association among allied males, alliance stability and male ranging patterns had little influence. In line with predictions for male alliances formed between unrelated individuals, we found that reproductive skew within alliances was not large. 5. Together, our genetic and behavioural analyses demonstrate that alliance formation between male dolphins is a successful strategy to enhance reproductive output.     

露蕊乌头(毛茛科)不同海拔居群的传粉生态学

对青藏高原东北部两个不同海拔地点（互助,2460m和海北,3200m）的露蕊乌头Aconitum gymnandrum的传粉生态学进行了比较研究。研究结果表明高海拔居群的单花花期、雄性期持续时间、雌性期持续时间比低海拔长。露蕊乌头不存在无融合生殖现象,尽管高度自交亲和,但产生种子必须依赖传粉媒介。熊蜂是露蕊乌头的主要传粉昆虫,两个居群均存在传粉限制。熊蜂取食花蜜为主,在同一个花序上的访问顺序以由下向上为主,但在互助居群和海北居群有3．9％和2．7％的访花是由上向下进行的。统计发现有37．7％和29．3％的访问行为发生在同一植株内;因此,同株异花传粉造成的自交在露蕊乌头中仍然不能避免。低海拔居群的熊蜂种类和访花频率均高于高海拔居群,但自然状态下两个居群的结实率并没有显著差异。高海拔露蕊乌头居群可能具有较长的柱头持续时间,从而补偿了由于访花频率低带来的结实率降低。     

Effects of floral display size and biparental inbreeding on outcrossing rates in Delphinium barbeyi (Ranunculaceae)

Floral display size represents a tradeoff between the benefits of increased pollinator visitation and the quantity of pollen received vs. the costs of increased self-pollination and reduced pollination quality. Plants with large floral displays often are more attractive to pollinators, but pollinators visit more flowers per plant. Intraplant foraging movements should increase self-pollination through geitonogamy, lowering outcrossing rates in large plants. Local genetic structure should also increase inbreeding and decrease outcrossing estimates, if pollinators move between neighboring, related plants. These predictions were tested in a population of larkspurs (Delphinium barbeyi) in Colorado. Allozymes were used to estimate outcrossing rates of plants varying in display size. Floral displays varied widely (2-1400 flowers; 1-26 inflorescences per plant), and outcrossing rate decreased significantly with increasing display size. Large, multistalked plants self over twice as frequently as single-stalked plants (46 vs. 21%). Local population structure is significant, and biparental inbreeding depresses outcrossing in plants surrounded by genetically similar neighbors. Protandry, coupled with stereotypical bottom-up pollinator foraging, reduces self-fertilization by autogamy or geitonogamy within inflorescences. Selfing is predominantly (>60%) by geitonogamy between inflorescences in large plants. Geitonogamy may be a significant cost to plants with large floral displays if inbreeding depression and/or pollen and ovule discounting results. If so, floral display size, particularly inflorescence number, may be under contrasting selection for pollination quantity vs. quality.     

甘肃乌头属二新种

描述了自甘肃发现的毛茛科乌头属二新种,合作乌头和莲花山乌头,并分别给出二种与其等近缘种的形态区别特征。     

毛翠雀花花序内的性分配和繁殖成功

两性花植物花序内不同位置的性分配和繁殖成功一般存在差异,通常认为资源竞争、结构效应和交配环境是形成这种差异的主要原因.为了研究雄性和雌性繁殖资源在花序内不同位置间的最优分配问题,该文以青藏高原高寒草甸典型高山植物毛翠雀花为材料,通过比较花序内不同位置的花部特征和种子性状,对其花序内的性分配模式和雌性繁殖成功进行研究,并...