鸢尾属植物的传粉者吸引及异交策略

已知鸢尾属(Iris)植物约有280种且花部特征多变,具有较高的科研和观赏价值。尽管该属植物具备一定的克隆和自交繁殖能力,但传粉者介导的异交仍在其物种和遗传多样性的维持中发挥重要作用,然而目前仍缺乏对该属植物传粉者吸引及异交策略的系统性总结。本文首先简述了鸢尾属植物的传粉者种类及其适应动物传粉的花部构造,以明确其动物传粉概况。在此基础上,详细论述了该属植物如何通过视觉和嗅觉信号呈现花粉、花蜜和热量报酬供给等策略,实现对传粉者的有效吸引。在传粉者访问前后,鸢尾属植物还可通过合理的花展示、单花内雌雄功能的时空隔离以及传粉后的调控以实现最大程度的异交。此外,影响其传粉者吸引及异交的第三方生物和非生物因素,如食花者和资源配置,也应受到重视。今后随着相关研究的深入和技术手段的革新,研究者应针对鸢尾属植物传粉的热点或有争议的问题,采用花信号定量测定及异交率分子检测等先进技术,通过大范围的对比研究,深入揭示鸢尾属植物与传粉者的互作模式及其繁殖策略。     

国产鸢尾属尼泊尔鸢尾亚属的研究

研究报道了国产鸢尾属尼泊尔鸢尾亚属植物,确认国产该亚属植物为三种一变种。     

鸢尾属植物的引种栽培

从１９６２年开始,我们就对鸢尾属植物进行引种栽培实验,结果表明：鸢尾属植物多数种在西安地区自然条件下,能正常生长发育。鸢尾属植物具有花姿奇特,花色艳丽,花期甚长等优点,是绿化、美化、香化城市,装饰花坛、花径、花带、路旁及草坪的优良材料。本文对我园引种鸢尾属植物的形态特征、生物学与生态学特性、栽培技术及其在园林绿化中的利用意见进行了初步报道。     

有花植物与传粉动物

绝大多数被子植物及少数裸子植物需要昆虫或动物传粉才能完成受精。除人们所广泛熟悉的蜂类、蝶蛾类是重要的传粉者以外,还有许多其它无脊椎动物和脊椎动物起着积极的传粉作用。传粉动物与植物之间的密切关系是生物之间互惠互益、协同适应的典范。一、无脊推动物传粉的植物 1.适于甲虫传粉的植物甲虫传粉是热带植物的特征,就象蜜蜂传粉是温带植物的特征。甲虫是昆虫中最古老的类型,     

鸢尾属植物的组织培养与栽培研究进展

鸢尾属植物花色艳丽,花型多具特色,具有较高的观赏性,是园林绿化中常见的一类花卉,也是世界著名的宿根花卉之一。鸢尾属植物在盆栽观赏、切花生产、医药食品、园林绿化等领域均占有重要地位,可以产生良好的经济效益、环境效益、生态效益和社会效益。但鸢尾属植物繁殖方式主要为分株繁殖,增殖缓慢。为解决这类问题,并对鸢尾属资源开发与保护提供理论基础,本研究对近年来国内外鸢尾属植物的组织培养与栽培的进展与成果进行了综述。本综述对鸢尾属植物育种的研究方向进行了探讨与展望,旨在为鸢尾属植物的培育方法提供一定的科学依据。     

鸢尾属植物的化学成分及其生物活性

鸢尾科鸢尾属植物的主要化学成分是黄酮类化合物,这类化合物具有广泛的生物活性。本文对近年来该属植物的分布,化学成分的分类及生物活性进行了综述。     

自交与异交象牙参属植物的蜜腺结构及其生物学意义

蜜腺是有花植物与传粉昆虫构建互惠关系的关键花部结构,解析不同繁殖特性物种间蜜腺结构的差异可为理解有花植物繁殖特性的演化提供理论依据。以传粉系统高度特化、异交实现有性生殖的早花象牙参（Roscoea cautleoides）和缺乏有效传粉者、主动自交实现有性生殖的无柄象牙参（R. schneideriana）为材料,通过野外测量2个物种蜜腺特性、超景深显微镜观察和石蜡切片染色,探究早花象牙参与无柄象牙参在蜜腺分布位置、外部形态及内部结构的异同。结果表明：2个物种均具有结构蜜腺,从外部形态来看,早花象牙参蜜腺体积较大、分泌糖浓度较高的花蜜,而无柄象牙参蜜腺体积较小、无花蜜分泌;从内部结构来看,早花象牙参蜜腺结构特化、各个组成部分有明显的区分,而无柄象牙参蜜腺出现一定程度的退化。该研究结果为揭示早花象牙参与无柄象牙参在花部特征、传粉机制及繁育系统的差异以及无柄象牙参蜜腺无花蜜分泌的可能机理提供了重要的形态学依据,也为深入地探讨植物与传粉动物间的协同进化关系以及理解蜜腺多样性的起源与维持机制奠定了科学基础。     

同域分布柽柳属两种植物的传粉生物学研究

以同域分布于新疆南部的早春开花植物短穗柽柳(Tamarix laxa Willd)和紫杆柽柳(T.androssowii Litw)为材料,对它们的开花式样、花部特征、花报酬特点、传粉特性及交配方式进行比较研究。结果表明,2种植物居群和个体水平的花期及单花寿命间存在显著差异;紫杆柽柳的居群花期比短穗柽柳短,而短穗柽柳个体花期和单花寿命比紫杆柽柳长。2种柽柳的花瓣、雌雄蕊长度、花粉胚珠数及花粉/胚珠比值(P/O)间也存在显著差异。二者的花瓣、雌雄蕊均能分泌香味,访花频率与花蜜量均存在正相关。主要传粉者在短穗柽柳上的访花频率和沉积花粉效率高于紫杆柽柳,且存在显著差异。2种植物通过自花和异花授粉均可结实,属于混合交配系统;二者的自交不亲和指数及花粉限制程度间存在显著差异;紫杆柽柳的自交亲和性高于短穗柽柳,而短穗柽柳的花粉限制指数高于紫杆柽柳。因此,2种柽柳的开花式样、花部特征及花报酬的差异,是它们在传粉者受限的早春环境中为吸引更多的访花昆虫、提高雌性繁殖率所形成的繁殖对策。     

国产13种鸢尾属植物的核型研究

对中国产13种鸢尾属Iris植物进行了核型研究。其中中甸鸢尾I.subdichotoma、长葶鸢尾I.delavayi、大锐果鸢尾I.cuniculiformis为中国特有。大锐果鸢尾的染色体数目及核型为首次报道,核型公式为2n=22=4m 6sm 12st(2SAT)。长管鸢尾I.dolichosiphon的核型为首次报道,核型公式为2n=22=4m 12sm 6st。中甸鸢尾的染色体数目为新报道,核型公式为2n=42=20m 22sm。矮紫苞鸢尾I.ruthenicavar.nana的染色体数目为新报道,3个居群的染色体数目均为2n=42,核型公式分别为中甸居群2n=42=30m 12sm(2SAT),丽江甘海子居群2n=42=28m 14sm(2SAT),中甸尼西居群2n=42=36m 6sm(4SAT)。结合以往的细胞学研究结果,显示尼泊尔鸢尾亚属subgen.Nepalensis是一个染色体数目变化较大的类群,其中的中甸鸢尾可能是联系野鸢尾属Pardanthopsis与尼泊尔鸢尾亚属的重要类群。已报道的紫苞鸢尾I.ruthenica染色体数目为2n=84,与我们所研究的变种矮紫苞鸢尾(2n=42)呈倍性关系,通过与相邻类群的分析比较,认为紫苞鸢尾应是由二倍体类群演化而来。还对鸢尾属内染色体数目的变化和核型进化的趋势进行了探讨。     

外来传粉者对本地植物-传粉者相互作用的影响

随着虫媒作物对传粉服务的需求日益增加,导致人工养殖的外来传粉者在全球范围内数量激增并大面积扩散,对本地植物-传粉者之间的互利关系造成极大影响,严重威胁当地生物多样性和生态系统稳定性。该文综述了外来传粉者对本地植物、本地传粉者以及传粉网络3个方面的影响。(1)外来传粉者与本地传粉者在形态特征和访花行为上的差异,使其对本地植物而言往往是低效或者无效的传粉者,从而对植物的繁殖成功造成负面影响;但是在传粉限制环境中,外来传粉者也可能起到重要的补充授粉作用。外来传粉者特定的访花偏好和对本地传粉者访花行为的影响会改变植物的花粉流和基因流,从而使植物种群的遗传结构发生变化。此外,外来传粉者会对植物的资源分配策略和花部结构发育施加新的选择压力,进而引导花部特征的适应性演变。(2)外来传粉者与本地传粉者会形成资源竞争或捕食关系,还可能干扰本地传粉者的生殖过程或造成病原体传播,从而对本地传粉者的物种多样性和丰富度构成极大威胁。(3)由于大多数外来传粉者都是泛化传粉者,促使它们能够很快整合到新生境的传粉网络中,与本地植物形成大量新的连接,往往使整个传粉网络的泛化水平和嵌套化程度升高,最终对传粉网络的稳定性产生深远影响。目前,我国针对外来传粉者的研究主要侧重于农业授粉应用,今后,应该更加重视外来传粉者进入自然生态系统后对本地开花植物、传粉者以及两者之间互作网络的结构和功能的影响机制研究,需要全面考虑物种、群落和生态系统3个不同的层次,同时扩展研究的地理尺度和时间尺度,在研究中注意结合新技术和新方法,并考虑全球变暖和农业集约化等趋势的影响。在外来传粉者在我国的分布区持续扩大的现状下,为保护本地植物和传粉者物种多样性,维持自然生态系统的原真性和稳定性,需要:(1)做好外来传粉者的引种规划和防控管理工作;(2)建立本地传粉者自然保护区,确定优先保护物种和优先保护区域;(3)大力开发和保护本地传粉者为农作物提供授粉服务,避免引入外来传粉者而导致生态危害。     

Pollen:ovule ratio and its relationship with other floral traits in Papilionoideae (Leguminosae): an evaluation with Argentine species

The pollen:ovule ratio (P/O) has traditionally been used as a rough estimator of plant breeding systems. It has been shown that plant breeding systems are associated with particular floral traits. In this study, we determined the P/O in 21 Leguminosae species from Argentina and explored relationships between P/O and taxonomic position, flower size, floral rewards, pollen presentation and pollination mechanisms. According to the results, 15 out of the 21 species classified were obligate xenogamous, although some of them have been recorded as facultative xenogamous in previous studies. There was a significant effect of taxonomic position (genus), reward type and pollination mechanism on P/O. Species offering only nectar as a floral reward (which were species with a brush mechanism) had a significantly lower P/O than species offering pollen or pollen and nectar. Species with the brush pollination mechanism had the lowest P/O, while species with valvular and pump mechanism had the highest P/O. However, pollen presentation (primary and secondary) and flower size did not have a significant effect on P/O. Our results demonstrate that P/O variability is determined by taxonomic position and pollination mechanism in this plant group.     

Floral traits and pollination systems in the Caatinga, a Brazilian tropical dry forest

BACKGROUND AND AIMS: Pollination is a critical stage in plant reproduction and thus in the maintenance and evolution of species and communities. The Caatinga is the fourth largest ecosystem in Brazil, but despite its great extent and its importance few studies providing ecological information are available, with a notable lack of work focusing on pollination biology. Here, general data are presented regarding the frequency of pollination systems within Caatinga communities, with the aim of characterizing patterns related to floral attributes in order to make possible comparisons with data for plant communities in other tropical areas, and to test ideas about the utility of syndromes. This paper also intends to provide a reference point for further studies on pollination ecology in this threatened ecosystem. METHODS: The floral traits and the pollination systems of 147 species were analysed in three areas of Caatinga vegetation in northeastern Brazil, and compared with world-wide studies focusing on the same subject. For each species, floral attributes were recorded as form, size, colour, rewards and pollination units. The species were grouped into 12 guilds according to the main pollinator vector. Analyses of the frequencies of the floral traits and pollination systems were undertaken. KEY RESULTS: Nectar and pollen were the most common floral resources and insect pollination was the most frequent, occurring in 69.9 % of the studied species. Of the entomophilous species, 61.7 % were considered to be melittophilous (43.1 % of the total). Vertebrate pollination occurred in 28.1 % of the species (ornithophily in 15.0 % and chiropterophily in 13.1 %), and anemophily was recorded in only 2.0 %. CONCLUSIONS: The results indicated that the pollination systems in Caatinga, despite climatic restrictions, are diversified, with a low percentage of generalist flowers, and similar to other tropical dry and wet forest communities, including those with high rainfall levels.     

The significance of flower colour change in eight co-occurring shrub species

Flower colour changes from white or yellow to various shades of red at or near the sites of harvestable pollen in Calytrix glutinosa, Grevillea pilulifera, Isopogon dubius and Petrophile biloba , and over most of the flower in Hypocalymma angustifolium, Verticordia chrysantha and V. huegelii and over the pseudanthium in Darwinia citriodora. All bee, wasp, beetle, fly, butterfly and moth visitors select flowers in the white/yellow phase rather than the red or intermediate phase.
Nectar is produced by five species, harvestable pollen by four species and detectable perfume by three species, all of which features are usually absent from the red phase. The timing of the colour change in all species also corresponds to loss of stigma receptivity, completion of pollination and onset of ovule seed) swelling. Six species also undergo minor morphometric changes which discourage visitation. In all species, colour change is non-inducible by pollinators, taking 2–30 days to complete. In three protandrous species, all available pollen may be removed in the first visit, requiring transport of non-self pollen to rewardless flowers during the 10 h period of the yellow phase.
These species are highly floriferous and occur in dense patches. Since only a small proportion of flowers may be receptive at any one time, it is concluded that retention of flower parts essentially serves to enhance long-distance attraction, while colour change maximizes pollination and foraging efficiency.     

Effects of number of flowers per raceme and number of racemes per plant on bumblebee visits and female reproductive success in <Emphasis Type="Italic">Salvia nipponica</Emphasis> (Labiatae)

We studied the adaptive arrangement of raceme flowers in dense and sparse habitats of Salvia nipponica. We recorded bumblebee visits and collected mature seeds to estimate outcrossing rates from allozyme genotypes. To examine the resource investment in flowering stalks, we measured their length and dry mass. We found that a greater number of open flowers in a raceme enhanced bumblebee visits and successive probings in both density plots. However, greater height of a raceme did not enhance these in plots of either density. In the high-density plot, both a greater mean number of open flowers in a raceme and a greater number of flowering racemes on a plant enhanced bumblebee visits, successive probings, and also enhanced outcrossing rate in spite of an increase in successive probings. Although the number of flowers per raceme had a greater positive effect on seed-to-ovule ratios than did the number of racemes, the number of flowers per raceme may be constrained because a longer flowering stalk needs greater buckling strength. Hence, it may be advantageous for plants in high-density plots to increase both number of flowers per raceme and number of racemes. In the low-density plot, a greater number of flowering racemes on a plant enhanced pollinator visits, but a greater mean number of open flowers in a raceme did not. Hence, it may be advantageous for plants to increase the number of racemes while keeping the numbers of flowers per raceme small. Thus, the adaptive number of flowers per raceme and number of racemes per plant may differ between high- and low-density plots.     

The reproductive biology of Stellera chamaejasme (Thymelaeaceae): A self-incompatible weed with specialized flowers

It has profound implications for species invasions and fitness, how weeds achieve reproductive success. We present the first study on the reproductive biology of Stellera chamaejasme, a toxic perennial weed which is abundant in the alpine meadows on the eastern Tibetan Plateau of China since the 1960s. S. chamaejasme has synchronogamy and herkogamous flowers, which last for about 11 days. Flowers can be yellow, white or reddish. Our results suggest that this species is self-incompatible and depends entirely on pollen vectors for seed production. All the pollinators observed were Lepidopteran species; however, the pollinator assemblage was significantly different among populations and likely independent on floral colour. Reproductive success and invasion of the weed might be a complex function of floral traits, breeding system and pollination ecology. Generally, plants with generalized pollination system are more invasive. However, our results suggest that specialized flowers and self-incompatibility in the present case may not prevent invasion of the weed.     

光温外界信号、植株状态与成花决定

植物由营养生长状态转向生殖生长状态（成花转变）是发育过程中的重要一步。经过一段时期营养生长的植株,便自动进入成花感受态,在这种状态下植株才能够对外界信号产生应答反应而启动成花过程。本文主要讨论光周期和温度对成花的作用     

土壤养分对蝴蝶花的花形态可塑性的影响

为了研究土壤养分对蝴蝶花的花形态可塑性的影响,在田间实验中对蝴蝶花进行了高、中、低养分（N、P、K）水平处理。实验表明,随着土壤养分水平的增加,外轮花瓣长和宽、内轮花瓣长和宽、雌蕊长、雄蕊长、花冠直径均逐渐增加。花各组成部分的形态大小间相关性显著（P=0．05）。结合花部形态特征对环境异质性的生态适应意义,对实验结果进行了讨论。     

Specialized pollination by spider-hunting wasps in the African orchid Disa sankeyi

Disa sankeyi Rolfe was found to be pollinated almost exclusively by Hemipepsis wasps (Pompilidae) at sites across its range in the Drakensberg mountains of South Africa. Wasps of both sexes appear to locate the cryptic yellow-green flowers primarily by using scent cues, as they show a classic zigzag flight pattern when approaching inflorescences. The sweet-spicy fragrance emitted by the flowers is strong enough to be discernable by a human from several metres away and consists of a blend of at least 65 volatile compounds, with (E)- cinnamic aldehyde and eugenol as the major constituents. On settling, wasps lick the exposed droplet of nectar that is secreted from the mouth of the reduced floral spur on each flower. Pollinaria become attached to the front feet of the wasps as they grasp flowers adjacent to those on which they are feeding. Pollen transfer to stigmas similarly takes place on flowers adjacent to those that are used as a nectar source. Almost 100% of flowers in the study populations were found to have been pollinated. Specialized pollination by pompilid wasps appears to be a rare phenomenon that has been reported only in southern African plant species. It appears to be associated with cryptic green-yellow flowers and highly accessible nectar. Behavioural assays are required to determine whether the basis of the specialization in this pollination system lies in a particular chemical composition of the floral fragrance.     

小慈姑的开花状态、传粉机制与交配系统

在自然种群中对沼生植物小慈姑（Sagittaria potamogetifolia Merr.）的开花状态和传粉过程作了观测,并用同工酶遗传标记法定量估测了其3个种群中5个样本的异交率。该种为中心媒传粉为主的虫／风 媒兼性传粉机制,访花昆虫的飞行距离多在0-2m范围内,并与花序密度呈不显著的正相关。异交率（－／^／t）为50.0％－92.8％,表明该种为异交为主的混合交配系统（ixed mating system）。对雌雄同株的小慈姑而言,异交率与各种群花期植株密度无关,异交水平取决于种群中开花花序的两个或两个以上的植株所占比例。