宝兴百合花柱偏转促进延迟自交试验研究

2011年7~8月对云南香格里拉高山植物园的宝兴百合(Lilium duchartrei Franch.)种群进行了传粉生物学研究实验,以期找到这种花朵开放初期雌雄异位的植物传粉生物学特点。结果表明,记录到的178次昆虫对宝兴百合的访问中能触碰到柱头的仅有蝴蝶类1次,有效传粉者传粉频率严重不足;单花期5.5~6.5 d,花开放的前3天,柱头远离花药,从花开放的第二天起花柱缓慢向上偏转,第四天将柱头从远离花药位置送到刚好可以接受自花花粉的位置,利于早期没有昆虫传粉的花朵延迟自交,自花授粉发生在花期末期,自交之前仍然保持异交传粉机制;自然状态(92.3%)及完全套袋处理(90%)的结实率接近,说明宝兴百合传粉存在花柱偏转促进的延迟自交,但2种处理的每果实种子数自然状态(121)显著高于完全套袋处理(78),又说明由昆虫传粉的异交更利于宝兴百合结实。延迟自交避免了自交与异交竞争造成的花粉或者种子的折损,为宝兴百合在有效访花昆虫不足导致异交失败时提供繁殖保障。     

Floral display and breeding system of Jatropha curcas L.

Plant flowering and breeding characteristics are important for us to understand the reproduction of plant populations. In this paper, we studied the reproduction characteristics of Jatropha curcas in Yuanjiang County (23°36′N, 101°00′E), Yunnan Province. The plant produces flowers in dichasial inflorescences. Normally, the flowers are unisexual, and male and female flowers are produced in the same inflorescence. Only a few male flowers are produced in an inflorescence, and fruits are produced only through pollination between different flowers from the same or different plants. By the treatments of emasculation, bagging and artificial pollination in this experiment, there were few but same fruit set ratios when the inflorescences were emasculated, bagged, or bagged with net, except artificial pollination treatments, which showed that Jatropha curcas could produce fruit through apomixis but not wind pollination. When the inflorescences were unbagged, unemasculated and with free pollination treatments, or bagged, emascu- lated and with artificial cross-pollination treatments, or unbagged, emasculated and with free pollination treatments, there were many fruits produced. It showed that Jatropha curcas shows outcrossing, is self-compatible, and demanding for pollinators. Normally, the male flowers open first and a few flowers bloom in one day in a raceme. These flowers last a long time in bloom. However, a large number of female flowers open from the third to the fifth day, with some female flowers opening first in a few raceme. This shows a tendency to promote xenogamy and minimize geitonogamy.     

杨梅授粉与花粉直感研究

选择20年生的荸荠种、东魁杨梅和水晶种3个杨梅品种雌株各3株,21年生实生雄优株、21年生荸荠种雌雄同株杨梅和12年生实生东魁雄杨梅进行3a授粉试验,研究杨梅授粉坐果的特性及若干果实性状的花粉直感规律.结果表明:杨梅花粉生活力较强,9d后仍达75.8％以上;杨梅坐果率与花粉生活力不成正比.雄株花粉对坐果率的花粉直感效应明显,即雄株花粉以实生东魁杨梅雄株花粉坐果率最高,平均21.47％;品种以水晶种坐果率最高,平均22.47％;年份以2008年坐果率最高,平均16.43％;雄株花粉与杨梅品种之间存在交互作用.人工授粉与自然授粉的坐果率趋势一致,各品种套袋后人工授粉的坐果率略低于自然授粉,套袋不授粉的不结果.不同雄株对不同杨梅品种成熟期和果实品质(如色泽、果实大小、风味等)的花粉直感现象不明显.     

授粉方式对黄连木座果率及果实性状的影响

研究抖授黄连木花粉、自然授粉、套袋不授粉3种授粉方式对黄连木座果率和果实性状的影响,结果表明,不同授粉方式之间座果率有显著差异:抖授黄连木花粉平均座果率最高,达到61.75%;套袋不授粉座果率最低;自然授粉介于二者之间。不同授粉方式对果实性状有显著差异,其中抖授黄连木花粉千粒重、空壳率及含油率最高,套袋不授粉最低,自然授粉介于二者之间。从研究数据可以得出结论,抖授黄连木花粉能显著提高座果率和果实性状,可以在生产上应用。       

Improving controlled pollination methodology for breeding <Emphasis Type="Italic">Acacia mangium</Emphasis> Willd.

Acacia mangium is a major plantation species for the pulp and paper industry in south-east Asia and there are a number of active breeding programs. The species is predominantly outcrossing, but with a demonstrated capacity to set selfed seed where outcross pollen is limited, with consequent inbreeding depression in the progeny. Current controlled pollination methods therefore include a time-consuming emasculation step. We used microsatellite genotyping of seedlings to determine the consequences of outcross pollination with and without emasculation. Only 1 of 3 mother trees set a small amount (5%) of selfed seed. Using whole inflorescences from the male parent as the pollen applicator rather than sieved pollen reduced outcross contamination rates from 19.1 to 8.7% and substantially increased worker productivity. Application of sugar solution to the female flowers immediately prior to pollination increased yield of sound seeds per spike. Additional improvements to the pollination protocols are discussed.     

Reproductive biology of the critically endangered tropical tree Talbotiella gentii

Talbotiella gentii is a critically endangered caesalpiniaceous legume endemic to Ghana, restricted in distribution to the margins of the forest zone where there has been extensive fire damage in recent decades. It occurs as isolated, near-monospecific populations, some of which show little seedling regeneration. We studied its reproduction to determine limitations that might inform efforts to prevent its extinction. We report on flowering phenology, pollen dispersal and germination, fruit and seed set, seed size and germination, and seedling survival, using controlled and open pollination. Talbotiella gentii flowers profusely in most years. Although the flowers are coloured and scented, no animal pollinators were observed but pollen can be dispersed by wind. In open pollination, the number of pollen grains on stigmas and their germination was sufficient to fertilise the three ovules, despite competition from heavy stigmatic infestation by fungal spores and hyphae. Fruit set and seed set were low due to high flower losses and fruit abortion during development but ripe seeds showed high germination. Controlled pollination experiments (self, supplemented self, and intra- and inter-population crosses) showed that, while the species is self-compatible, selfing was the least successful treatment in all of the above steps of reproduction, whereas cross-pollination enhanced most steps, the more so for inter-population crosses. Seed size was notably greater in inter-population crosses and was positively correlated with genetic distance of the cross. The larger seeds associated with cross-pollination showed higher germination and seedling survival in the nursery. We conclude that limitations to natural reproduction in T. gentii are principally due to processes between pollen germination and fruit and seed set, including pollen quality (low genetic diversity and inbreeding), fertilisation rates, flower and fruit abortion, and resource limitation. Low seed size in open and self pollination may have implications for seedling establishment. Species fitness might be improved by introducing other genotypes to existing populations, but in situ protection of the populations is essential in the medium term.     

Bats and bees are pollinating Parkia biglobosa in The Gambia

A pollination experiment was conducted with Parkia biglobosa (Fabaceae) in The Gambia. P. biglobosa is integrated in the farming systems and produces fruit pulp and seeds used in cooking. The species is bat-pollinated, and in areas with few bats the main pollinators are assumed to be honey bees. A higher rate of effective pollination will in many instances increase fruit production, and the aim of this study was to investigate pollination efficiency of different pollinators. Access of flower visiting animals to flowers was controlled by nets with differently sized mesh, using five trees as replicates. The pollinators’ identity, efficiency, and relative effect were determined. Bats, honey bees, and stingless bees were able to pollinate the species. Bat-visited capitula produced more pods, but not significantly more than honey bees. Honey bees were more efficient than stingless bees, resulting in significantly less aborted seeds. The treatment which excluded all flower visitors developed no mature pods, indicating that P. biglobosa was not autonomous autogamous, apomictic, or parthenocarpic, while the treatment with confined honey bees showed that geitonogamy is possible. Sugar content of fruit pulp was analysed and a positive correlation between number of seeds per pod and the sugar content was found. Improved pollination success may thus result in sweeter fruits. We conclude it is important to strive against a pollinator-friendly environment in order to attract bats and bees. Furthermore, we suggest beekeeping in the vicinity of P. biglobosa as a way to increase yield.     

Density-dependent selfing and its effects on seed performance in a tropical canopy tree species, Shorea acuminata (Dipterocarpaceae)

In the conservation and management practices of natural forests, sound reproduction and regeneration form the basis of the maintenance and viability of the tree populations. To obtain and serve biological information for sustainable forest management, we investigated reproductive biology and inbreeding depression in seeds of an important dipterocarp tree species, Shorea acuminata (Dipterocarpaceae), by both field and laboratory experiments. Results of parental analysis of immature and mature seeds showed that selfing rates varied greatly, from 7.6 to 88.4% among eight mother trees, and the mean overall selfing rate was 38.3%. Observed outcrossing events within a 40-ha study plot were predominantly (76.5%) short-distance events with a mating distance (md) ≤ 100 m. Since the selfing rate sharply decreased with increase in the number of flowering conspecifics (i.e., individuals of the same species) within a 100-m radius from the mother trees, the local density of flowering conspecifics appears to be the key factor determining the outcrossing rate in S. acuminata. However, the extremely high selfing rate (88.4%) observed for one tree could not be simply explained by the low local density of flowering conspecifics. Instead, differences in its flowering phenology (its flowering peaked ca. a week earlier than most of the other examined individuals) may have severely limited its receipt of pollen from other conspecifics, and thus promoted selfing. Since there were no significant differences in the proportion of selfed progeny between immature and mature seed stages, there was no evidence of selective abortion of selfed seeds during seed development. However, the seed mass of outcrossed progeny was heavier than that of selfed progeny, and heavier seeds showed higher success rates at germination and seedling establishment. These results suggest that inbreeding depression resulted in reductions in seed mass and may reduce the fitness of selfed seeds in S. acuminata. In addition, the outcrossing rate of S. acuminata was more sensitive to low local conspecific flowering-tree densities than that of a sympatric bee-pollinated dipterocarp species with greater pollination distances. These results suggest that the management of local adult-tree densities is important for avoiding selfing and inbreeding depression in future generations, especially in a species like S. acuminata with predominantly short-distance pollination.     

罗平县银杏人工授粉试验初报

以罗平县境内已栽培上百年的古银杏雄树和1999年引种的银杏品种大梅核雌树为试验对象,开展银杏雌雄树花成熟期观察和人工授粉试验。通过2004～2007年连续4年的观察,罗平县银杏雄花成熟时间为3月25日至4月1日,各年略有不同,可将雄花序成熟与雌花成熟视为同步。2007年配制含0.2%花粉和3.3%白糖的花粉液,采用混水喷雾法开展银杏人工授粉试验。试验结果,罗平县银杏人工授粉平均坐果率达94.5%,表明在罗平县开展银杏人工授粉的初步试验是成功的。     

EST-SSRs development and paternity analysis for <Emphasis Type="Italic">Liriodendron</Emphasis> spp

Liriodendron are ideal plants for research on mating system, systemic evolution and population genetics. Here we report the development and application of a set of simple sequence repeat (SSR) markers derived from expressed sequence tags (ESTs) of L. tulipifera. In total, 176 primer pairs were developed and yielded 132 EST-SSR markers that amplified clear SSR bands with genomic DNA of L. tulipifera. Transferability of these EST-SSR markers to related species and genera was further examined. Twelve highly informative loci screened from 132 EST-SSR markers were applied to explore the effective pollen dispersal patterns and male reproductive success of Liriodendron. A provenance trial population of Liriodendron comprised 12 L. chinense (Hemsl.) Sarg provenances and 5 L. tulipifera provenances. The four maternal trees were randomly sampled as tested maternal trees in the population. Paternities of 220 open-pollination progenies from 4 maternal trees above were potentially identified by means of paternity analysis, of which 138 progenies (accounting for 62.7%) were assigned to 49 male parents at the 95% confidence level. The cumulative exclusion probability of 12 EST-SSR loci was 98.5%. The average effective pollen dispersal distance of pollen donors ranged from 15 to 35 m, with the maximum dispersal distance of 77 m. There were obvious male reproductive success differences among individuals, ranging from 0 to 10.9%. The cumulative male reproductive success of individuals within 35 m radius around the known maternal trees reached 51.4%. Diversiform mating patterns, including selfing, intra-species mating and interspecies mating, coexisted in the occasion of open-pollination in Liriodendron.     

Reproductive biology of Corymbia citriodora subsp. variegata and effective pollination across its native range in Queensland,Australia

The spotted gum species complex represents a group of four eucalypt hardwood taxa that have a native range that spans the east coast of Australia, with a morphological cline from Victoria to northern Queensland. Of this group, Corymbia citriodora subsp. variegata (CCV) is widespread in south-eastern Queensland and northern New South Wales. It is currently the most commonly harvested native hardwood in Queensland. However, little basic knowledge of the reproductive biology of the species is available to inform genetic improvement and resource management programmes. Here we take an integrative approach, using both field and molecular data, to identify ecological factors important to mating patterns in native populations of CCV. Field observation of pollinator visitation and flowering phenology of 20 trees showed that foraging behaviour of pollinator guilds varies depending on flowering phenology and canopy structure. A positive effect of tree mean flowering effort was found on insect visitation, while bat visitation was predicted by tree height and by the number of trees simultaneously bearing flowers. Moreover, introduced honeybees were observed frequently, performing 73% of detected flower visits. Conversely, nectar-feeding birds and mammals were observed sporadically with lorikeets and honeyeaters each contributing to 11% of visits. Fruit bats, represented solely by the grey-headed flying fox, performed less than 2% of visits. Genotyping at six microsatellite markers in 301 seeds from 17 families sampled from four of Queensland's native forests showed that CCV displays a mixed-mating system that is mostly outcrossing (t _m = 0.899 ± 0.021). Preferential effective pollination from near-neighbours was detected by means of maximum-likelihood paternity analysis with up to 16% of reproduction events resulting from selfing. Forty to 48% of fertilising pollen was also carried from longer distance (>60 m). Marked differences in foraging behaviour and visitation frequency between observed pollinator guilds suggests that the observed dichotomy of effective pollen movement in spotted gums may be due to frequent visit from introduced honeybees favouring geitonogamy and sporadic visits from honeyeaters and fruit bats resulting in potential long-distance pollinations.     

中国特有种枝毛野牡丹传粉生物学及繁育系统研究

对海南吊罗山国家级自然保护区枝毛野牡丹（Melastoma dendrisetosum）的开花进程,访花昆虫、访花行为、访花频率以及气候条件等进行观察记录,同时检测了花粉活力、柱头可授性、花粉胚珠比、繁育系统,并分析其致濒机制。结果表明：枝毛野牡丹是典型的异型雄蕊植物,5：30—8：30逐步开放,8：30—9：00完全开放,19：00花朵闭合,单花开放时间为12—14 h,群体花期36±2 d,无花蜜。访花昆虫主要有木蜂科、条蜂科、蚁科、食蚜蝇科的昆虫,最有效传粉昆虫为木蜂科昆虫。自然与人工授粉、套袋等试验结果表明,枝毛野牡丹不存在主动自花授粉、无融合生殖的生殖保障现象,为自交亲和的异交种,需要昆虫传粉,枝毛野牡丹繁育系统是兼性自交。枝毛野牡丹相对生殖成功率低仅为0.035,主要限制因子为花粉限制和传粉者限制。     

Comparison of different control-pollination techniques for small-flowered eucalypts

Controlled pollination (CP) is a labour-intensive, but useful procedure applied in tree improvement programmes. However, the high costs involved and relatively low seed yields often obtained has, in most cases, necessitated the use of lower quality, open pollinated seed. The aim of the present study was to compare control-pollination methods for combinations among small-flowered eucalypt species. By making crosses within and among Eucalyptus grandis, E. smithii and E. macarthurii, we compared effectiveness, in terms of seed production and level of genetic contamination, of three CP techniques, namely emasculation of bagged flowers and subsequent pollination of receptive stigmas (Conventional method), emasculation and immediate pollination of stigmas with induced receptivity followed by bagging (One Stop Pollination), and pollination of cut styles without emasculation and bagging (Artificially Induced Protogyny). One tree of each species was used as the female in these crosses. Although Artificially Induced Protogyny using ripe and semi-ripe buds produced the highest seeds/flower pollinated in the majority of crosses carried out in this study, the technique, when performed on green buds, resulted in the highest capsule abortion. Molecular analysis using microsatellite markers also revealed that progeny from the Artificially Induced Protogyny method, when using green and semi-ripe buds, were highly contaminated by self- and external pollen. Of the three CP-techniques tested, One Stop Pollination had the lowest genetic contamination. However, this technique also had one of the lowest seed yields, while the Conventional method was intermediate in performance.     

小桐子繁育系统与传粉生态学研究

在野外定位观测小桐子花朵的功能形态特征、开花动态、传粉方式,用杂交指数(OCI)、花粉/胚珠比(P/O)、去雄、套袋、人工授粉等方法分别测定小桐子的繁育系统.结果显示:(1)小桐子是单性花,雌雄同株同序.雄花单花期2 d,雌花单花期5～8 d,雌花直径略大于雄花.(2)雄花开花后9 h内花粉活力较高,24 h后花粉活力明显降低,48 h后花粉基本散失活力;雌花柱头可授性在开花后4 d内最强,5～8 d可授性开始降低,第9天基本失去可授性.(3)传粉方式以虫媒传粉为主,为虫媒植物.(4)繁育系统检测结果为部分自交亲和异交,需要传粉者活动才能完成授粉过程.     

Phenotypic variation of baobab (<Emphasis Type="Italic">Adansonia digitata</Emphasis> L.) fruit traits in Mali

We analyzed the phenotypic variation of baobab (Adansonia digitata L.) fruits from Mali to define the domestication potential of this species. 269 trees, selected from 10 provenances distributed along a rainfall gradient, were characterized. Five fruits were sampled from each tree. Total individual fruit weight was partitioned into shell, pulp, and seed weight. Ratios were calculated between pulp + seed and total weight, and between pulp and seed weight. For all the measured fruit traits, we detected significant differences between provenances, as well as between trees from the same provenance. Assuming that the measured traits are under genetic control, the latter facts indicate that there are considerable opportunities for tree selection on a local scale. However, candidate plus trees with specific properties, e.g., extremely high pulp or seed weight, were found only in some locations. Mean pulp yield per fruit might be considerably increased by selecting the 5% trees with the highest pulp weight (mean: 45 ± 1 g, best 5%: >100 g). The same might be true for seed production (mean: 71 ± 2 g, best 5%: >150 g). Also the ratio between pulp and seed weight can be an important fruit characteristic for selection: in fruits with a low ratio, relatively more pulp sticks to the seeds when separating the two fruit parts by grinding, and thus more pulp will be lost for further processing. We identified several trees with a high pulp weight combined with a high ratio between pulp and seed weight. It is concluded that there is considerable phenotypic variability in traits of baobab fruit in Mali, offering opportunities for cultivar selection.     

Domestication potential of Marula (<Emphasis Type="Italic">Sclerocarya birrea</Emphasis> subsp. <Emphasis Type="Italic">caffra</Emphasis>) in South Africa and Namibia: 3. Multiple trait selection

An understanding of the inter-relationships between the traits characterising tree-to-tree variation in fruits and kernels is fundamental to the development of selected cultivars based on multiple trait selection. Using data from previously characterised marula (Sclerocarya birrea) trees in Bushbuckridge, South Africa and North Central Region of Namibia, this study examines the relationships between the different traits (fruit pulp, flesh/juice mass, and nut shell and kernel mass) as a means to determine the opportunities to develop cultivars. Strong and highly significant relationships were found between fruit mass and pulp mass in trees from South Africa and Namibia, indicating that size is a good predictor of fruit pulp production. However, fruit size is not a good predictor of nut or kernel production, as there were weak relationships between fruit and nut and/or kernel mass, which varied between sites and landuses. Generally, the relationships between fruit mass and kernel mass were weaker than between fruit mass and nut mass. Relationships between kernel mass and shell mass were generally weak. The lack of strong relationships between fruit and kernel mass does, however, imply that there are opportunities to identify trees with either big fruits/small nuts for pulp production, or trees with large kernels in relatively small fruits for kernel oil production. However, within fruits from the same tree, nuts could contain 0–4 kernels, indicating that even in trees with an inherent propensity for large kernels, improved pollination may be required to maximise kernel mass through an increase in kernel number. Finally, the relationships between percentage kernel oil content and the measured morphological traits were also very weak. The conclusions of these results are that there is merit in identifying different combinations of traits for the selection of trees producing either pulp or kernels. Consequently, fruit and kernel ‘ideotypes’ are presented as guides to the selection of elite trees for cultivar development. These results have important implications for the domestication of the species as a producer of fruits or kernels for food/beverages or cosmetic oils.     

保护地栽植矮甜李授粉方法选择试验

日光节能温室内种植的矮甜李选择授粉方法是获得高产的关键。通过人工点授、自然授粉、室内放蜂、液体授粉 4种方法的对比 ,总结出 4种授粉方法的坐果率为人工点授 (3 1 .0 7% ) >室内放蜂 (2 1 % ) >液体授粉 (9.5 3 % ) >自然授粉 (0 .1 6% ) ,从试验结果看出 ,保护地种植矮甜李必须进行辅助授粉 ,否则无产量。从经济、快捷、简便的角度出发 ,以室内放蜂为最佳授粉方法 ,放蜂量为 1 0 0 0头 /棚。     

苹果授粉特性研究进展

苹果是异花授粉树种，授粉是影响其果实品质的重要因素。花粉形态、生活力等直接影响授粉效果；雌蕊的生长发育对受精有着重要的影响；柱头有效授粉期的长短决定授粉品种的选择；光照、气温、空气湿度、风以及传粉方法都对授粉效果有着重要的影响。授粉程度影响果实形状和大小，授粉品种的性状影响果实的果形指数等品质性状。     

竹类植物花粉的生活力和自然授粉

对12种开花竹类植物花粉的败育、生活力和自然授粉进行了观察和试验研究，花药和花粉在离体后生活力保存时间较短，尤其是离体花粉的生活力在1－2h会丧失贻尽，适宜竹花粉萌发的培养液的10％蔗糖液，若再加入5ppm硼酸能明显提高花粉发芽率。篌竹和斑苦 花分别属于花药合并粘连和无花粉的二类雄性不育型，其余10个竹种的花粉中均有三种类型的败育花粉，低温、干旱等不育环境使竹花粉发育受阻，不育花粉率增高，竹花的自然授粉不良，在盛花的竹株上接受不到花粉的竹花占33．3％，在部分开花的竹株上花粉自然授粉率公10％。     

Effects of selective logging on the mating system and pollen dispersal of Hymenaea courbaril L. (Leguminosae) in the Eastern Brazilian Amazon as revealed by microsatellite analysis

Using nine microsatellite loci, we studied the effects of selective logging on genetic diversity, mating system and pollen dispersal in a population of the tree species Hymenaea courbaril, located in a 546 ha plot in the Tapajós National Forest, Pará State, Brazil. We analyzed 250 offspring (nursery reared seedlings) collected after a logging episode from 14 open-pollinated seed trees. These were compared to 367 seedlings from 20 open-pollinated seed trees previously collected from the pre-logging primary forest. The genetic diversity was significantly lower in the post-logging seed cohort. In contrast to the pre-logging population, significant levels of selfing were detected in the post-logging population (t_m = 0.962, P < 0.05). However, correlated matings were reduced and the effective number of pollen donors almost doubled after harvesting (3.8 against 7.2). Logging also reduced pollen immigration into the plot (from 55% to 38%) and we found no significant correlation between the size of the pollen donors and the number of seeds fathered. Inside the plot, pollen dispersal distance was shorter before logging than after (827 and 952 m, respectively) and the reproductive pollination neighbor area (A_ep) was larger (average of 178 ha). The individual and average variance effective population size within families (ranged from 1.80 to 3.21, average of 2.47) was lower than expected in panmictic populations (N_e = 4). The results indicate that while logging greatly reduced the levels of genetic diversity after logging, it also increased genetic recombination within the population and constrained crossing among related individuals. The results show that low-density tropical tree species such as H. courbaril, when harvested in moderate levels may be resilient to a reduction in the reproductive population and may maintain similar levels of outcrossing and pollen dispersal after logging.