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1.
Medicago sativa L. is an important cash crop in the arid region of northwest China. Pollinator activity is an essential aspect of pollination success, but the relationships between pollinator visitation rate and seed set still need further study of M. sativa. We investigated the following characteristics of M. sativa in natural and managed populations: floral traits, pollinator activity, and breeding system. Our results indicated the management could affect the number of flowers produced; however, there was no detectable effect on the seed set per flower. We found the percentage of seeds among pollinated flowers in the managed population was significantly higher than that in the natural population. Moreover, the increase in the proportion of pollinated flowers could significantly increase seed set per flower, and pollinator visitation rate was the important limiting factor for seed set in both populations. Andrena lebedevi Popov was found to be the most frequent pollinator in both populations. Outcrossing was dominant in the breeding system and insect pollination played an important role in outcrossing. Our study suggested that proper management (artificial selection) could promote pollination success of M. sativa. 相似文献
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To predict the effect of global warming on plant reproductive success, seed-sets of spring ephemerals were compared between a year of extremely warm spring (2002) and normal years at cool-temperate deciduous forests in northern Japan. The spring of 2002 was the warmest in the last 40years and most spring-ephemeral plants bloomed 7–17days earlier than usual. The seed-set of bumblebee-pollinated Corydalis ambigua drastically decreased in 2002 in every population. The small bee-pollinated Gagea lutea also significantly decreased in 2002. However, the seed-sets of two fly pollinated species, Adonis ramosa and Anemone flaccida, were not influenced by early flowering. These results indicat that the effect of global warming on seed production of spring ephemerals differs between species depending on the type of pollinators, and that bee-pollinated species can have serious impacts on reproductive success as a result of climate change. 相似文献
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对迁地保护的珍稀濒危植物猬实的开花动态、花粉活力、柱头可授性、访花昆虫种类、访花频率、花粉与胚珠比(P/O)、异交指数(OCI)进行观测.结果表明：猬实的单花期约为7 d,种群花期约为14 d,花冠展开后2~3 h,花粉活力达到最高,约为90％,3 d后花粉基本不具活力.在整个单花期,柱头一直具可授性,花冠展开后第2天可授性最强.花粉与胚珠比(P/O)为(398．1±63．7),异交指数(OCI)为3,表明猬实是以异交为主,自交亲和的繁育系统,有时需要传粉者完成传粉过程.猬实的访花昆虫有10余种,以膜翅目蜜蜂科和隧蜂科昆虫为主,另外还有少量双翅目食蚜蝇科昆虫,偶见鳞翅目的柑橘凤蝶和长喙天蛾,其中以蜜蜂科蜜蜂属昆虫传粉效率最高.迁地保护的猬实未见结籽,其原因还有待于进一步研究. 相似文献
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MARIANA TADEY JORGE C. TADEY NATALIA TADEY 《Botanical journal of the Linnean Society. Linnean Society of London》2009,161(2):190-201
Research into plant breeding systems enables the evaluation of whether seed production depends on pollination agents and gene flow mechanisms within and among populations. This aids, in turn, the estimation of the appropriate population sizes needed to maintain both genetic and species' diversity. Little is known about plant reproductive biology in the Monte Desert (Patagonia, Argentina), a habitat threatened by desertification as a result of human impact. The mating systems, flowering phenologies and pollinator networks were studied in five representative plant species of the Monte Desert. The mating systems studied ranged from anemophilous pollen dispersion in the dioecious Atriplex lampa, to a gradient of dependence on pollinators, from the less dependent (facultative self‐compatible) Gutierrezia solbrigii and two Larrea spp. (L. divaricata and L. cuneifolia) to the most dependent Grindelia chiloensis (self‐incompatible). Flowering phenology was restricted to spring and coincided with pollinator abundance. Solitary bees were the main pollinator group, but beetles, flies and butterflies were also important. The four insect‐pollinated species were moderately generalist, but they maintained their own pollinator assemblage. Coleopterans depended more on Grindelia chiloensis and dipterans on Gutierrezia solbrigii. Lepidopterans frequently visited Gutierrezia solbrigii and Larrea divaricata, whereas hymenopterans visited both Larrea spp. more frequently. The studied plant species are ecologically important, not only as resources for a wide range of pollinator species but also for other insects. The Monte Desert is a very disturbance‐sensitive environment and, as these plant species hardly show vegetative regeneration, sexual reproduction is essential for their survival. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161 , 190–201. 相似文献
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Yoshiaki Kameyama Manami Watanabe Hideki Kurosawa Takuya Nishimori Daisuke Matsue Masaaki Takyu 《Ecology and evolution》2015,5(22):5352-5363
Flowering phenology of alpine plants is strongly determined by the timing of snowmelt, and the conditions of pollination of widely distributed plants vary greatly during their flowering season. We examined the reproductive success of the distylous alpine herb, Primula modesta, along the snowmelt gradient under natural conditions, and compared it with the result of artificial pollination experiments. In addition, the compositions and visit frequencies of pollinators to the flower of P. modesta were examined during the flowering period. The pin and thrum plants of P. modesta growing at the same site have an equal ability to produce seeds if a sufficient amount of legitimate pollen grains are deposited on the stigma surface. However, under natural conditions, their seed‐set success was often (even if not always) restricted by pollen limitation, and the functional gender of the pin and thrum plants biased to the female and male, respectively, associated with their growing sites. These variations were not ascribed to resource limitation nor biased morph ratio but to the seasonal changes in pollination situations, a replacement of pollinator types from long‐ to short‐tongued pollinators resulted in unidirectional pollen transfer from long stamens (thrum plants) to long styles (pin plants). The functional gender specialization may enhance the evolution of dioecy from heterostyly, but the severe pollen limitation may cause the breakdown of heterostyly into homostyly. To consider the evolutionary pathway of heterostylous plants, an accumulation of the empirical data is required demonstrating how phenological synchrony between plants and pollinators is decided and to what degree this relationship is stable over years, along with estimates of selection and gene flow in individual plants. 相似文献
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野外定点观测了夏蜡梅在3个群体的开花物候进程,分别计算了结实率和结籽率,并分析了始花日和开花同步性等开花物候指数对其传粉成功的影响,还进一步从个体水平分析了开花时间对传粉成功的影响.结果如下:夏蜡梅的花期在5月上旬到6月下旬,开花物候参数在不同群体间存在较明显的差异,而各群体的开花进程均呈明显的\"单峰型\",且开花同步性高,为\"大量开花模式\".群体内各开花物候参数与传粉成功相关性不明显;群体间开花物候参数中的始花日和开花中值日与结实率呈极显著的负相关,终花日与结实率和结籽率分别呈极显著和显著的负相关.个体水平不同开花时间对结实率有着显著影响(F=15.960,df=3,P＜0.01),而对结籽率影响不大(F=2.358,df=3,P=0.073).相同海拔高度小生境不同对夏蜡梅的传粉成功影响不大,但不同海拔高度对夏蜡梅的传粉成功影响显著.作为一种濒危物种,夏蜡梅这种\"集中开花模式\"可以吸引更多的传粉昆虫,有助于其获得更多的传粉成功,但增加了其花粉在个体内及邻近个体间的传递,不利于花粉在群体间的扩散,而导致了一定程度的自交和近交衰退,这可能是夏蜡梅群体遗传变异性低、遗传分化明显及濒危的一个原因. 相似文献
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在广东鼎湖山,华南云实(LaesalpiniacristaL.)始花期从2月或3月开始,开花后约1周达到盛花期,盛花期持续2~4d,花期可持续到4月底。华南云实基本繁育系统为雌蕊先熟、自交不亲和的异花受精。华南云实传粉方式为风虫媒。其主要传粉者为膜翅目昆虫,该种是云实属植物中首次报道的可行风媒传粉的种类。描述并探讨了华南云实花的结构与其主要传粉者木蜂之间的互动适应,并讨论了传粉生物学实验中的一些处理方法对华南云实开花过程的影响。 相似文献
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开花物候是物种间相互作用的重要生活史特征和适合度因子,在全球气候变化的背景下而备受关注.为探讨开花时间如何存种内和种间水平上影响植物的传粉和生殖成功,我们连续3年(2003-2005)对不同花期和伴生种存在情况下的鹤首马先蒿(Pedicularis gruina)的传粉者访花忠实度、受粉率、坐果率、单果种子产量和果实被啃食频率进行了比较研究.结果表明鹤首马先蒿的坐果率主要受其传粉环境的影响:在没有伴生种时,不同时期鹤首马先蒿的坐果率没有显著差异,34-38％的花可以坐果;在有伴生种存在时既可以显著提高其坐果率,也可显著降低其坐果率,这取决于传粉者类型以及伴生种密穗马先蒿(P.densispica)花期的差异.密穗马先蒿具有花蜜和花粉双重报酬,在群落中可以作为主体物种吸引传粉者并间接促进与其伴生的鹤首马先蒿的传粉和生殖成功.同样无蜜的管花马先蒿(P.siphonantha)和鹤首马先蒿伴生,则是通过提高群落水平对传粉者的吸引力进而直接促进鹤首马先蒿的传粉和生殖成功.此外,研究结果也表明开花时间对坐果率没有显著影响,但是显著影响单果种子产量和果实被啃食的频率.在相同的传粉条件下早花期植株单果种子产量显著高于晚花期的种子产量,同时早花期的果实被啃食的频率显著增加. 相似文献
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Climate change has led to phenological shifts in flowering plants and insect pollinators, causing concern that these shifts will disrupt plant-pollinator mutualisms. We experimentally investigated how shifts in flowering onset affect pollinator visitation for 14 native perennial plant species, six of which have exhibited shifts to earlier flowering over the last 70 years and eight of which have not. We manipulated flowering onset in greenhouses and then observed pollinator visitation in the field. Five of six species with historically advanced flowering received more visits when flowering was experimentally advanced, whereas seven of eight species with historically unchanged flowering received fewer visits when flowering earlier. This pattern suggests that species unconstrained by pollinators have advanced their flowering, whereas species constrained by pollinators have not. In contrast to current concern about phenological mismatches disrupting plant-pollinator mutualisms, mismatches at the onset of flowering are not occurring for most of our study species. 相似文献
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The genus Cymbidium comprises three subgenera with ca. 50 species. Interactions between pollinators and plants have been studied in the two subgenera Cymbidium and Cyperorchis, but only a few studies in the subgenus Jensoa have been reported. Here we report on the reproductive characteristics of C. goeringii (in sub-genus Jensoa) in three populations in the southwest of Hunan Province, China, during the winter from December 2005 to March 2006. Floral phenological and morphological features, behavior of visitors, the breeding system, and fruit sets under natural conditions were studied. The flowers of C. goeringii were strongly fragrant, but did not present any rewards to the visitors. The flowering period of C. goeringii in the studied populations lasted about 40 days, and most flowers (about 60%) opened within 30 days. Flowers opened immediately when temperature increased obviously and reached to about 16 ℃. The flowering time of the pollinated flowers, unpollinated flow-ers and the flowers with pollinarium removed were similar. Two bees of Apidae, Apis cerana cerana (honeybee) and Anthophora melanognatha, were observed visiting flowers of C. goeringii, but only the honeybees performed as pollinators. The honeybees mostly visited the orchid flowers at 10:00–17:00 on sunny days with temperature above 10 ℃. A total of only thirteen visits were observed during 20 days of observation, indicating pollinators were rare. Honeybees directly landed on the upper surface of the labellum and inserted their heads into the flowers between column and labellum, while the hind legs trod on the surface of the curved downward mid-lobe of label-lum. When a honeybee landed on the labellum of a flower, the labellum moved up and down slightly. After the honeybee entered the flower further, its head might touch the foot of the column. At this time, the body of the honeybee was parallel with the upper surface of the labellum. Then the honeybee used its front legs to scratch on the callus ridges on the upper surface of the labellum, and its hind legs hooked the edges of the side lobe of label-lum, trying to exit forcibly from the flower. During exiting process, sometimes the honeybee’s body was arched owing to tension. In this case, the surface of the scutellum came into close contact with the viscidium and then pollinaria, together with the anther cap, were removed. When this honeybee visited next flower, the pollinaria would be adhered to the stigma when it arched its body during the exiting process. Three plant species flowered synchronously with C. goeringii in the studied areas, but their flowers were different with C. goeringii in color or shape. Because C. goeringii is rewardless to pollinators, the flowers probably attract visitors by olfactory stimu-lus. Breeding system experiments showed no spontaneous autogamy and pollination success relying on pollinators in C. goeringii. Artificial pollination resulted in 90% fruit set by induced autogamy, 100% by pollinating within clone, and 100% by xenogamous pollination, respectively. These results indicate that C. goeringii is highly self-compatible and the fruit production is pollen limited. Because pollinators are essential for fruit set of C. goeringii in natural habitats, protection of wild honeybee populations or apiculture is likely a simple but effective strategy to maintain the orchid populations. 相似文献
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Many plant species reward their pollinators, whereas some species, particularly among orchids, do not. Similarity of floral cues between co‐flowering species influences how rapidly pollinators learn to avoid deceptive plants. This learning process, which affects the reproductive success of deceptive plants, may additionally depend on relative timing of flowering of sympatric rewarding and deceptive species. We tested the combined effects of corolla colour similarity and flowering order of rewarding and deceptive artificial inflorescences on visitation by naïve bumblebees. When deceptive inflorescences were offered after rewarding inflorescences, bumblebees visited them four times more often if both species were similar compared with when they were dissimilar. Pollinator visitation rate to deceptive inflorescences offered before rewarding inflorescences was intermediate and independent of similarity. Thus, early‐flowering deceptive species avoid the costs of dissimilarity with rewarding species. This mechanism may favour adaptive evolution of flowering phenology in deceptive species and explain why temperate deceptive orchids usually flower earlier than rewarding ones. 相似文献
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Jin B Wang L Wang J Teng NJ He XD Mu XJ Wang YL 《Plant biology (Stuttgart, Germany)》2010,12(6):853-862
The formation and ecological roles of sterile flowers in flowering plants are interesting issues in floral biology and evolution. Here, we investigated the morphological and anatomical characteristics of both fertile and sterile flowers of Viburnum macrocephalum f. keteleeri, a self-incompatible and insect-pollinated shrub, during different developmental stages of flowers. In addition, pollinator visitation rates and fruit set were determined in intact inflorescences and those with sterile flowers removed. The results indicate that sterile and fertile flowers were developmentally similar during early developmental stages, and that development of the flower types diverged about 15 days before flowering. In addition, pollinator visitation rates, number of pollen grains on stigmas and fruit set were significantly higher in inflorescences with sterile flowers than those without sterile flowers. The results suggest that sterile flowers of this species evolved from fertile flowers under long-term selective pressure, and play a crucial role in enhancing reproductive success through effectively attracting pollinators to the plant and thus enhancing fruit set. 相似文献
16.
《Plant Ecology & Diversity》2013,6(2-3):97-104
Background: The arrangement of flowers on inflorescences is important for determining the movement of pollinators within the inflorescence and, consequently, the overall mating success and fruit set of a plant.Aims: Spiranthes spiralis is an orchid that has a spiralled inflorescence. The species has two chiral forms that show opposite coiling directions (clockwise and anti-clockwise). We tested if this arrangement of inflorescence influences pollinator attraction and behaviour.Methods: We surveyed two natural populations, analysed the reproductive compatibility of the two morphs and estimated pollination success in natural and experimental populations.Results: We found that the two morphs were not isolated by pre- or post-mating barriers, occurred with a similar proportion in natural populations and showed similar levels of pollination success both in natural and artificial populations. However, we found a different pattern of pollination success along the inflorescences. In the two morphs, lower flowers experienced a higher pollination rate and this rate decreased along the inflorescence faster in anti-clockwise than in clockwise individuals.Conclusions: This finding suggests that pollinators visit the flowers sequentially from the lower part of the inflorescences and leave the anti-clockwise individuals more rapidly than the clockwise ones. However, this pollinator behaviour is not detrimental for the pollination success of either of the two morphs. 相似文献
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陕西羽叶报春为中国珍稀濒危植物,研究其开花物候、传粉者及访花行为、花粉活力、柱头可授性、繁育系统,以明确陕西羽叶报春的传粉特性及制濒机制。以勉县陕西羽叶报春野生居群为研究对象,通过野外观察和人工授粉实验首次对陕西羽叶报春的传粉生物学进行研究。结果表明:(1)陕西羽叶报春种群花期为2-4月中旬,单花花期一般为14~17 d;单花开花进程中花部形态有6个明显发育变化:全部被萼片包裹、花苞伸出并为深粉色、花朵打开为淡粉色、花冠为白色、花朵枯萎、花冠脱落花萼宿存。(2)陕西羽叶报春为异花授粉植物,蜜蜂属为其主要传粉者。(3)柱头在花粉未开裂前就具有可授性,可授性逐渐增强;花药在花瓣打开后的第3天才开始开裂、散粉,在第4天活力最高,为98.18%,此后逐渐减弱。(4)繁育系统检测显示,长、短柱型花的花粉/胚珠比分别为902.26和831.48,杂交指数为4;套袋实验显示,陕西羽叶报春异型交配可育,同型交配不可育。由此表明,陕西羽叶报春的繁育系统为异交型,自交不亲和,需要传粉者。综上所述,陕西羽叶报春传粉者种类少、自交不亲和、胚珠败育现象可能是导致陕西羽叶报春濒危的重要原因。 相似文献
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以陕西镇坪化龙山地区的东亚七筋姑自然居群为对象,通过重力玻片法、套袋法和人工授粉对其进行连续的传粉生物学观察和研究,以明确其散粉规律和繁育系统.结果表明,东亚七筋姑的花期在五月中下旬,单花花期2～3 d,整个花序的花期随花序大小的不同而异,一般为3～7 d;东亚七筋姑为虫媒传粉,其访花昆虫大多为小型昆虫,主要种类有小型甲虫、蚁类和蝇类等;东亚七筋姑自花传粉是可育的,存在异花传粉,不存在无融合生殖,自然条件下结籽率为58%,人工异株异花授粉结籽率为82%.可见,东亚七筋姑的繁育系统为兼性异交类型,需要传粉者. 相似文献
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DIEGO MEDAN ANA C. D'AMBROGIO 《Botanical journal of the Linnean Society. Linnean Society of London》1998,126(3):191-206
Various aspects of the reproductive biology of the andromonoecious shrub Trevoa quinquenervia Gill. & Hook, were studied in a population located in central Chile. Flowering extends from mid August to the end of December. The small, white, entomophilous flowers are incompletely protandrous and last c. 5 days. A weak, pleasant odour along with nectar and pollen attracts 17 diurnal insect species, seven of which are probable pollinators: these include Diptera (Syrphidae and Bombyliidae), Hymenoptera (Apidae and Colletidae) and Coleoptera (Melyridae). Besides perfect flowers T. quinquenervia individuals possess c. 10% staminate flowers, which are lighter, seem to be shorter-lived, and show a smaller gynoecium with abnormal ovules. Reproduction is exclusively sexual and apparently xenogamous, with pollen transfer depending on insect vectors. Although flower morphology and individual flower phenology do not fully prevent self-pollination (and geitonogamy can easily take place) the level of autogamy is low. Therefore, some self-incompatibility mechanism seems operative in this species. Fruit set of open-pollinated flowers is 6.6%, and ripe fruits contain on average 0.66 viable seeds. Predispersal (maternal) reproductive success (percent ovules becoming viable seeds) is 1.45%. For medium to full-sized individuals this corresponds to c. 2600 to 8600 potential offspring per year. Beyond the production of male flowers, four other aspects of the species' reproductive biology seem directed to enhance pollen export, partly implying increased male allocation: (a) a high pollen:ovule ratio, (b) protection of anthers against pollen-robbing by means of the cucullate petals, (c) secondary pollen presentation in a hairy barrier located above the nectary, and (d) a reduction in female allocation achieved by the regular abortion of two out of the three ovules in each ovary, thus producing a mostly one-seeded fruit provided with a thin, energy-poor pericarp. It is proposed that the advantages of enhanced pollen flow for a self-incompatible organism, which is moreover structured in isolated populations, might explain the increased male effort, including the joint evolution of andromonoecy and one-seededness. 相似文献
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Gidi Ne'eman Andreas Jürgens Linda Newstrom‐Lloyd Simon G. Potts Amots Dafni 《Biological reviews of the Cambridge Philosophical Society》2010,85(3):435-451
Measuring pollinator performance has become increasingly important with emerging needs for risk assessment in conservation and sustainable agriculture that require multi‐year and multi‐site comparisons across studies. However, comparing pollinator performance across studies is difficult because of the diversity of concepts and disparate methods in use. Our review of the literature shows many unresolved ambiguities. Two different assessment concepts predominate: the first estimates stigmatic pollen deposition and the underlying pollinator behaviour parameters, while the second estimates the pollinator's contribution to plant reproductive success, for example in terms of seed set. Both concepts include a number of parameters combined in diverse ways and named under a diversity of synonyms and homonyms. However, these concepts are overlapping because pollen deposition success is the most frequently used proxy for assessing the pollinator's contribution to plant reproductive success. We analyse the diverse concepts and methods in the context of a new proposed conceptual framework with a modular approach based on pollen deposition, visit frequency, and contribution to seed set relative to the plant's maximum female reproductive potential. A system of equations is proposed to optimize the balance between idealised theoretical concepts and practical operational methods. Our framework permits comparisons over a range of floral phenotypes, and spatial and temporal scales, because scaling up is based on the same fundamental unit of analysis, the single visit. 相似文献