片断化生境中滇桐传粉生物学和繁育系统

通过野外观察和人工授粉试验方法,对云南省文山州西畴县法斗分布区片断化生境中濒危植物滇桐(Craigia yunnanensis)的传粉生物学特征和繁育系统进行研究.结果表明:滇桐每个聚伞花序有2～9朵两性花,单花花期为3～4d,单花雌雄蕊在时空上有一定的隔离;杂交指数(OCI) ＞4,花粉-胚珠比(P/O)为1381±53;有效传粉昆虫为大头丽蝇(Chrysomyia megacephala);同株异花授粉结实率低;滇桐的繁育系统属于异交为主,部分自交亲和,传粉过程需要传粉者;自然状态下滇桐的座果率(56.67％±3.85％)和结籽率(6.26％±0.75％)均较低,而异株异花授粉均可显著提高座果率及结籽率(P＜0.01),这与当前片断化生境中传粉昆虫少、效率低下等有关,表明生境片断化正在影响滇桐植株的早期生殖成功.     

濒危植物南川升麻传粉生物学的研究

南川升麻（ＣｉｍｉｃｉｆｕｇａｎａｎｃｈｕａｎｅｎｓｉｓＨｓｉｓｏ）的繁育系统以异交为主,传粉昆虫主要为蝇类,盛花时的访花频率平均每花每天１１次,雄蕊脱落后约０６次;单穗升麻（Ｃ．ｓｉｍｐｌｅｘＷｏｒｍｓｋ）以虫媒为主,风也可以帮助其花粉在近距离传播。单穗升麻的传粉昆虫有蝇类和蜂类,盛花时的访花频率蝇类为１．４次,蜂类为１．２次。南川升麻和单穗升麻都是靠大的花序和气味来吸引传粉昆虫,报酬是退化雄蕊基部分泌的蜜液。自然条件下南川升麻每个柱头上平均有４枚花粉,结籽率平均为６４％,而单穗升麻每个柱头上平均有１７枚花粉,结籽率平均为４５９％。南川升麻有性生殖中传粉的限制是其致濒的重要因素之一。     

蛛网萼开花物候、花部特征及繁育系统研究

为探讨蛛网萼(Platycrater arguta)传粉生物学特性,该研究以江西上饶广丰铜钹山国家级自然保护区、江西阳际峰国家级自然保护区蛛网萼为材料,采用野外观察和人工授粉等方法,对蛛网萼开花物候、花部形态及繁育系统进行了研究。结果表明:(1)蛛网萼为伞形花序,种群花期一般在6月中下旬至8月中旬,单花花期为2~3 d,花序花期持续10 d。两个保护区由于年均温度与光照的不同,花期进程有显著不同。(2)蛛网萼可孕花与不孕花从绿色变为白色时对访花昆虫有吸引作用,不孕花能够增加昆虫的访花频率。(3)蛛网萼花粉胚珠比(P/O)为2 520~3 100,杂交指数即是3或4。(4)繁育体系属于以异交为主,部分自交亲和,需要传粉者;熊蜂(Bombus sp.)、四条蜂(Apis florea)和油茶地蜂(Andrena cammelia)是蛛网萼的有效传粉昆虫。(5)套袋和人工授粉结果显示,蛛网萼为兼性自交和异交授粉,异株异花授粉能显著提高坐果率及结籽率,这主要与生境中有效传粉昆虫种类、数量少,花粉传递效率低,种群间基因流交流降低以及柱头自花及同株异花传粉等有关,从而表明在蛛网萼现有生境中植株的早期生殖成功受到影响。蛛网萼种群分布范围扩张以有性繁殖为主,无性繁殖作为重要补充及繁殖保障。     

华南云实传粉生态学

在广东鼎湖山,华南云实(Laesalpinia crista L.)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2～4 d,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.     

珍稀濒危植物猬实的开花特性与传粉生物学研究

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.     

珍稀濒危植物瑶山苣苔开花生物学及繁育系统研究

对仅分布于广西金秀老山自然保护区的国家Ⅰ级保护植物瑶山苣苔进行了开花生物学和繁育系统研究.结果显示:(1)瑶山苣苔花期从8月底至11月初,开花无固定时间.单花开放过程可分为萌动、露白、盛开、凋落4个阶段,且花朵具明显的增大再生长现象.(2)单花、花序、单株水平上的开花物候都表现出开花不同步性,单花花期约5~14 d,单花序花期约11~20 d,单株花期约8~20 d.花粉活力在散粉后6 d内相对较高,但花粉在野外通常于散粉3 d内被昆虫啃食完.(3)柱头在花药散粉时明显高于花药,便于接受异花花粉,柱头在散粉后第4天具可授性,可持续5~6 d.(4)瑶山苣苔杂交指数(OCI)为5,花粉-胚珠比(P/O)为379.64±145.61,繁育系统为兼性异交,自交亲和,传粉过程需要传粉媒介.研究表明,不稳定的传粉环境可能是该物种至濒的主要生殖生物学原因,自发自交"是其在开花期间对不稳定传粉环境的一种适应.     

中国特有种——沙芥繁育系统和传粉生物学研究

运用定位观察、杂交指数、花粉-胚珠比、套袋试验和重力玻片法等方法,对沙芥自然居群和人工栽培种群的开花日动态、繁育系统和传粉习性进行了研究.结果显示:沙芥在自然居群和人工栽培种群开花日高峰分别在19:00和15:00～18:00.沙芥繁育系统为异花授粉植物.沙芥传粉媒介中风的飘移能力非常微弱;沙芥自然居群的访花昆虫有19种,分属于6个目;人工栽培种群的访花昆虫有11种,分属于6个目.意大利蜜蜂、熊蜂、黑带食蚜蝇和拟蜂食蚜蝇是两个居群共有的主要传粉昆虫,在自然居群熊蜂每天的访花频率呈双峰曲线,其中访花最高峰与开花日高峰基本重叠.     

短柄五加开花及传粉生物学研究

本文对短柄五加（Ｅｌｅｕｔｈｅｒｏｃｏｃｃｕｓｂｒａｃｈｙｐｕｓ）的花期物候、开花式样、访花昆虫种类、访花行为及访花频率进行了观察,对花粉活力、柱头可授性、花粉胚珠比以及传粉效果和繁育系统做了检测。初步结果表明,短柄五加以根茎进行无性繁殖,１个居群为１个无性系。虽自交亲和,但昆虫的访花活动可显著提高座果率。昆虫传粉主要在无性系内异花间进行,属于广义的自花传粉。传粉者为多种不同的昆虫,包括马蜂和胡蜂在内的蜂类、蝇类和甲虫。其花期物候、花粉活力、柱头可授期和蜜汁分泌期等特征使其能够适应环境,从而获得较高的座果率。平均座果率为６５％,饱满种子率为４５．５％。自然条件下未发现实生苗,广义的自花传粉导致的种子质量低下可能是其原因,也是限制短柄五加分布范围的重要因素。     

濒危药用植物云南黄连传粉生态学研究

云南黄连为中药材黄连的原植物之一,为国家二级濒危保护植物。通过对云南黄连的开花物候、花部特征、繁育系统及传粉方式进行观察研究,以探讨云南黄连濒危机制,为其种质资源保护及人工抚育奠定基础。结果表明:(1)云南黄连的花期从12月份起至第二年的3月份,花期长达4个月,花序开花可持续45～60d,同一花序上不同花的开花时间相隔1～3d,单花花期可持续40～45d。(2)云南黄连为多歧聚伞花序,苞片包被花芽,花两性,雄蕊和心皮多数。(3)云南黄连的花粉-胚珠比(P/O)为9 000左右,杂交指数(OCI)值为4或5,为自交亲和但需要传粉者完成传粉的兼性异交型繁育系统,并存在无融合生殖现象。     

毛菍传粉生物学研究

为探讨毛菍(Melastoma sanguineum Sims.)传粉生物学特性,对海南霸王岭国家级自然保护区林缘、林内和林隙3个生境内毛菍的花期、花部形态、访花昆虫等进行观察,同时对其繁育系统相关指标进行了测定。结果表明：毛菍无花蜜分泌;花瓣对访花昆虫有吸引作用;访花昆虫主要有蜂类、食蚜蝇类和丽金龟类;主要传粉昆虫有木蜂、熊蜂,其中木蜂传粉活动最为活跃,为最有效传粉昆虫。毛菍具典型的异型雄蕊,长、短雄蕊在传粉过程中具有明确的功能分化,推测这是毛菍保证传粉成功的策略。毛菍为自交亲和的异交种,需要昆虫传粉;人工自交和异交均具有较高的坐果率;不存在无融合生殖、主动自花授粉和滞后自交的生殖保障现象;其繁育系统是兼性自交。昼夜温差较小和相对湿度较高的林内和林隙生境有利于延长群体花期;光照充足、温度相对较高的林缘生境,花朵发育较快,柱头可授性的时间稍早。花粉、传粉者和环境条件是制约毛菍野外传粉效率的主要因素。     

Pollination by flies, bees, and beetles of Nuphar ozarkana and N. advena (Nymphaeaceae)

Nuphar comprises 13 species of aquatic perennials distributed in the temperate Northern Hemisphere. The European species N. lutea and N. pumila in Norway, the Netherlands, and Germany are pollinated by bees and flies, including apparent Nuphar specialists. This contrasts with reports of predominant beetle pollination in American N. advena and N. polysepala. We studied pollination in N. ozarkana in Missouri and N. advena in Texas to assess whether (1) there is evidence of pollinator shifts associated with floral-morphological differences between Old World and New World species as hypothesized by Padgett, Les, and Crow (American Journal of Botany 86: 1316-1324. 1999) and (2) whether beetle pollination characterizes American species of Nuphar. Ninety-seven and 67% of flower visits in the two species were by sweat bees, especially Lasioglossum (Evylaeus) nelumbonis. Syrphid fly species visiting both species were Paragus sp., Chalcosyrphus metallicus, and Toxomerus geminatus. The long-horned leaf beetle Donacia piscatrix was common on leaves and stems of N. ozarkana but rarely visited flowers. Fifteen percent of visits to N. advena flowers were by D. piscatrix and D. texana. The beetles' role as pollinators was investigated experimentally by placing floating mesh cages that excluded flies and bees over N. advena buds about to open and adding beetles. Beetles visited 40% of the flowers in cages, and flowers that received visits had 69% seed set, likely due to beetle-mediated geitonogamy of 1st-d flowers. Experimentally outcrossed 1st-d flowers had 62% seed set, and open-pollinated flowers 76%; 2nd-d selfed or outcrossed flowers had low seed sets (9 and 12%, respectively). Flowers are strongly protogynous and do not self spontaneously. Flowers shielded from pollinators set no seeds. A comparison of pollinator spectra in the two Old World and three New World Nuphar species studied so far suggests that the relative contribution of flies, bees, and beetles to pollen transfer in any one population depends more on these insects' relative abundances (and in the case of Donacia, presence) and alternative food sources than on stamen length differences between Old World and New World pond-lilies.     

Heterostyly and gene-flow in Menyanthes trifoliata L. (Menyanthaceae)

NIC LUGHADHA, E. M. & PARNELL, J. A. N., 1989. Heterostyly and gene-flow in Menyanthes trifoliata L. (Menyanthaceae). Menyanthes trifoliata is shown to be a self-incompatible heterostylous species with a suite of associated pollen and gynoecium dimorphisms. These features may promote legitimate pollination. Analysis of a natural population showed substantial pollen inviability, a preponderance of illegitimate pollen on stigmas and a possible asymmetry of pollen flow. Mean pollen travel was estimated as 2.6 m by counting legitimate grains on stigmas whose distance from the nearest source of legitimate pollen was known. Direct field and laboratory measurement indicated mean seed travel of <0.2m. The density of flowering spikes varied greatly within the studied colony of Menyanthes , with a mean of 0.93 m^-2. Using suitable corrections the genetically effective density was estimated as between 0.04 and 4.4 m^-2. Crossing experiments indicated that Menyanthes is fully outcrossed (r=1). The neighbourhood area was estimated as 10–15 m² while neighbourhood size ranged from less than one to sixty-five. Some published neighbourhood estimates are revised with the results for Menyanthes being at the lower end of the range. If the genetically effective density were estimated more accurately, neighbourhood estimates would likely be lower still. It is concluded that what is generally referred to as a population of Menyanthes , may actually represent many evolutionary units.     

白刺属4种植物传粉特性的实验研究

根据对乌兰布和沙漠地区白刺属4种植物在花期进行的人工控制性授粉实验及室内外调查分析,系统研究了唐古特白刺、西伯利亚白刺、大白刺和泡泡刺4种白刺属植物的传粉特性。结果表明:不同白刺属植物兼具杂交亲和与自交亲和的能力,更倾向于异交结实。繁育系统属于自交、异交相混合的兼性异交交配系统,存在风媒传粉的可能性,不能进行无融合生殖。白刺属植物的这些传粉特性表现出对干旱荒漠地区恶劣环境的较强生态适应性。     

Crane flies and microlepidoptera also function as pollinators in Epidendrum (Orchidaceae: Laeliinae): the reproductive biology of E. avicula

Crane flies and microlepidoptera have been recorded as pollinators in unrelated orchid groups, but these insects have never been recorded in Epidendroideae, the most species‐rich orchid subfamily, which includes one of the most diverse genera among Orchidaceae, Epidendrum. Based on data on phenology, floral morpho‐anatomy, pollinators, pollination mechanisms and breeding system, the reproductive biology of E. avicula was studied in south‐eastern Brazil. Epidendrum avicula possess osmophores that produce a citric fragrance at night. The flowers attract Tipulidae flies and several families of microlepidoptera that drink the nectar produced in a tube formed by the adnation of the labellum and column. As is common in Epidendrum, after removing the pollinarium, both crane flies and micro‐moths get trapped by the proboscis, which frightens the insects and inhibits any possible intent to immediately visit another flower. The behavior of the pollinators on flowers, plus the retention of the anther cap by the pollinarium, results in a reduction in the occurrence of geitonogamy. Because E. avicula is self‐incompatible, the consequence of pollinator behavior and the floral mechanisms tend to reduce the pollen loss. As far as we know, this is the first study to report the reproductive biology of a species of Epidendroideae pollinated by crane flies and microlepidoptera. Based on more recent concepts of plant–pollinator interactions, although E. avicula is pollinated by several species belonging to two distinct orders, suggesting an unspecialized pollination system is involved, nectar‐seeking microlepidoptera and Tipulidae flies can be recognized as a single functional group.     

Pollination biology of Lilium japonicum var. abeanum and var. japonicum: evidence of adaptation to the different availability of diurnal and nocturnal pollinators

Floral traits such as color and size are highly diversified in lilies, but their adaptive significance remains uncertain. In the present study, we compared pollination processes between Lilium japonicum var. abeanum and var. japonicum to clarify how the two varieties are adapted to different pollinators. Lilium japonicum var. japonicum is known to be pollinated by moths, and we hypothesized from its flower traits that var. abeanum is pollinated by diurnal insects. Using waterproof digital cameras set to a recording interval of 10–30 s, we recorded flower visitors for 7–9 flowers of var. japonicum and 4–6 flowers of var. abeanum over 24‐h periods. We also recorded the number of versatile (T‐shaped) and rigid (I‐shaped) anthers per flower. For var. abeanum, we observed flowers at 05.00 and 17.00 hours to determine flower opening time and measured the intensity of floral scent using a metal‐oxide semi‐conductor odor sensor. Both diurnal and nocturnal insects visited flowers of the two varieties, but visitation of diurnal insects was more frequent in var. abeanum. Anthers of var. abeanum are usually rigid, as in many bee‐pollinated flowers, whereas those of var. japonicum are mostly versatile. Although flowers of var. japonicum are known to open in the evening, 32% of the flowers of var. abeanum started to flower during the day. Lilium japonicum var. abeanum emitted scent at night, with a maximum intensity at 20.00 hours, just as in var. japonicum. These findings suggest that the floral traits of the two varieties are adapted to the different relative availabilities of nocturnal versus diurnal pollinators. The flower of var. abeanum is more adapted to diurnal pollinators, but retains adaptations to nocturnal pollinators, particularly with regard to its scent.     

Structure and Dynamics of Natural Populations of Polyploid Trilliums. V. Predominant Self-pollination in Trillium apetalon-T. smallii Association

Abstract Predominant self-pollination was confirmed in mixed populations of Trillium apetalon (4x = 20, SSUU) and T. smallii (6x = 30, K₁K₁SSUU). In pollination tests conducted on both species from the Muroran (Mr) population, many good seeds were obtained from bagged flowers as well as open-pollinated intact flowers. In striking contrast, fruits from castrated open-pollinated flowers failed to give any good seeds. In T. smallii in the Usu (Us) population, the same results were obtained for bagged and open-pollinated intact flowers. On the other hand, fruits from castrated open-pollinated flowers yielded only a few good seeds. Although both species were experimentally cross-compatible in both directions, no interspecific hybrids have so far been found in nature. It may be possible that both species are isolated by predominant self-pollinatioin even though their flowering seasons coincide.     

Pollination of endangered Cuban cycad Microcycas calocoma (Miq.) A.DC.

Observations indicate that natural regeneration in the field of the cycad Microcycas calocoma (Miq.) A.DC. is extremely low, and has been so since early this century. It appears that populations of its insect pollinator are practically extinct, but some pollinator activity appears to be present in the largest population of Microcycas. Recommendations for identification and captive breeding of die pollinator are suggested as a complementary conservation strategy to a Microcycas propagation programme already established at the Cuban National Botanical Garden.     

Beyond the pollination syndrome: nectar ecology and the role of diurnal and nocturnal pollinators in the reproductive success of Inga sessilis (Fabaceae)

Inga species present brush‐type flower morphology allowing them to be visited by distinct groups of pollinators. Nectar features in relation to the main pollinators have seldom been studied in this genus. To test the hypothesis of floral adaptation to both diurnal and nocturnal pollinators, we studied the pollination ecology of Inga sessilis, with emphasis on the nectar secretion patterns, effects of sequential removals on nectar production, sugar composition and the role of diurnal and nocturnal pollinators in its reproductive success. Inga sessilis is self‐incompatible and pollinated by hummingbirds, hawkmoths and bats. Fruit set under natural conditions is very low despite the fact that most stigmas receive polyads with sufficient pollen to fertilise all ovules in a flower. Nectar secretion starts in the bud stage and flowers continually secreting nectar for a period of 8 h. Flowers actively reabsorbed the nectar a few hours before senescence. Sugar production increased after nectar removal, especially when flowers were drained during the night. Nectar sugar composition changed over flower life span, from sucrose‐dominant (just after flower opening, when hummingbirds were the main visitors) to hexose‐rich (throughout the night, when bats and hawkmoths were the main visitors). Diurnal pollinators contributed less than nocturnal ones to fruit production, but the former were more constant and reliable visitors through time. Our results indicate I. sessilis has floral adaptations, beyond the morphology, that encompass both diurnal and nocturnal pollinator requirements, suggesting a complementary and mixed pollination system.