Reproductive ecology in Mexican Annonaceae: What do we know?

PDF HTML阅读 XML下载 导出引用 引用提醒 蝶形花亚科植物花部适应机制与传粉系统 DOI: 10.5846/stxb201301180120 作者: 作者单位: 兰州大学 草地农业生态系统国家重点实验室,兰州大学 草地农业生态系统国家重点实验室,兰州大学 草地农业生态系统国家重点实验室,兰州大学 草地农业生态系统国家重点实验室,兰州大学 草地农业生态系统国家重点实验室,兰州大学 草地农业生态系统国家重点实验室,兰州大学 草地农业生态系统国家重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（31270558）；兰州大学中央高校基本科研业务费专项资金（lzujbky-2013-86） Floral morphology and its relationship with pollination systems in Papilionoideae Author: Affiliation: State Key Laboratory of Grassland Agro-Ecosystem,School of Pastoral Agriculture Science and Technology,Lanzhou University,State Key Laboratory of Grassland Agro-Ecosystem,School of Pastoral Agriculture Science and Technology,Lanzhou University,State Key Laboratory of Grassland Agro-Ecosystem,School of Pastoral Agriculture Science and Technology,Lanzhou University,State Key Laboratory of Grassland Agro-Ecosystem,School of Pastoral Agriculture Science and Technology,Lanzhou University,State Key Laboratory of Grassland Agro-Ecosystem,School of Pastoral Agriculture Science and Technology,Lanzhou University,State Key Laboratory of Grassland Agro-Ecosystem,School of Pastoral Agriculture Science and Technology,Lanzhou University,State Key Laboratory of Grassland Agro-Ecosystem,School of Pastoral Agriculture Science and Technology,Lanzhou University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:蝶形花亚科（Papilionoideae）植物种类丰富、繁育系统多样，与其传粉者关系密切，主要表现在花部适应与传粉系统的形成。蝶形花形态复杂，为完全花，花萼、花瓣5基数，花萼呈箭头状，相邻花瓣螺旋轮生，旗瓣较大位于最外边，两片翼瓣紧贴旗瓣着生并包裹两片合生的龙骨瓣，龙骨瓣内包裹着雌、雄蕊，雌蕊位于正中央，雄蕊轮生，构成二体雄蕊（多数9+1，少数5+5）。对蝶形花亚科植物的花部特征、传粉功能群、酬物与传粉系统构建进行了回顾，重点论述了蝶形花形态和化学组成与传粉系统的进化关系以及花粉呈现机制。其中，泛化的传粉系统以蜂媒传粉为主，同时存在鸟媒传粉、蝙蝠传粉和松鼠传粉等方式，花部结构和传粉者的相互选择和相互适应推动了传粉系统的演化。花粉释放是体现蝶形花植物与其传粉功能群相互作用的重要方面，二者协同进化形成了以下4种花粉呈现机制：弹花机制、活塞机制、瓣膜机制和毛刷机制。蝶形花的花部特征与传粉功能群的相互作用形成相应的传粉系统，而传粉系统是执行传粉功能的重要集合体，各个构件的相互协调和适应保证了蝶形花亚科植物传粉过程的顺利完成。 Abstract:The formation of the diverse pollination systems in Papilionoideae is greatly dependent on the relationships between species richness and their functional groups of pollinators. The floral morphology in Papilionoideae plants is complex. The flowers of most taxa of Papilionoideae have a full complement of organs: pentamerous alternating whorls of sepals, petals, two stamen whorls and a single carpel. The floret has a median sagittal sepal, a bigger vexillum on the outside, and two wings close to the vexillum that parcel two keels of contention. The ten stamens are usually united into two groups (mainly 9+1, few 5+5), called diadelphous stamens. In this paper, we reviewed floral syndrome, functional groups of pollinators, rewards and pollination system in Papilionoideae. Particularly, floral morphology and chemical compositions and their relationships with evolution of pollination systems and mechanism of pollen release were discussed. Pollination system in Papilionoideae plants is mainly bee pollination, with avian pollination, squirrel pollination and bat pollination also present. The pollination system is usually an evolutionary outcome of selection and adaptation between floral morphology and pollinators. The mechanism of pollen release is one of the most important characters that exemplify such interactions between Papilionoideae plants and their pollinators. There are four pollen release mechanisms in Papilionoideae, explosive mechanism, piston mechanism, valvular mechanism and brush mechanism. The selection and adaptation between floral syndrome and the functional groups of pollinators established the pollination system, in which the coordination and adaptation among the components are essential for successful pollination. 参考文献 相似文献 引证文献

Plant-pollinator interactions range from obligatory specialists to facultative generalists, and floral morphology and pollination system may not match completely. The floral biology, reproductive system and floral visitors of a species of the tribe Rhipsalideae were investigated with a focus on the consistency between the pollination system and the floral phenotype. Rhipsalis neves-armondii is an obligate xenogamous species, due to self-sterility. Its flowers are white, small and diurnal, and radially symmetrical. These features, along with their small amount of nectar, characterize the flowers as phenotypic generalists. The most frequent pollinators were a solitary oligolectic species of Andrenidae (Rhophitulus solani), two species of Meliponinae (Trigona spinipes and T. braueri) and Apis mellifera. Despite the generalist floral phenotype, the pollination system is functionally specialized, since only small bees performed effective visits. Flowers of R. neves-armondii may represent a case of cryptic floral specialization in which attributes other than morphology act as filters, restricting them to a single functional group of pollinators. Moreover, the four most frequent species of pollinators cover a spectrum ranging from solitary oligolectic to social polylectic bees, including an exotic species. These results illustrate the distinct dimensions of specialization-generalization that may occur in the pollination process of a single species.

The study of insect reproductive ecology is essential to determine species distributions and fate under changing environments. Species adapted to harsh environments are good examples to investigate the reproductive mechanisms that allow them to cope with the challenging conditions. We here focus on studying for the first time the reproductive ecology of a cold-adapted Drosophila obscura (Diptera: Drosophilidae) strain collected in Finland (subarctic climate region). We tested several reproductive traits such as fertility and fecundity to observe the onset of reproduction and gauge when sexual maturity is reached in both males and females. We combined these measures with an analysis of changes of their reproductive organs shortly after eclosion. We found that males matured several days before females and that this process was underpinned by female egg maturation and male accessory gland growth, while sperm was already present in two-day old males. This delayed maturation is not observed to the same extent in other closely related species and might be a signature of exposure to harsh environments. Whether this delay is an adaptation to cope with variation in resource availability or prolonged unfavorable temperatures is though not clear. Finally, our study adds to the set of reproductive mechanisms used by cold adapted species and the information presented here contributes to understanding the breadth of Drosophila reproductive ecology.

We used cladistic analysis of chloroplast gene sequences (ndhF and rpl16) to test biogeographic hypotheses in the woody genus Gleditsia. Previous morphological comparisons suggested the presence of two eastern Asian-eastern North American species pairs among the 13 known species, as well as other intra- and inter-continental disjunctions. Results from phylogenetic analyses, interpreted in light of the amount of sequence divergence observed, led to the following conclusions. First, there is a fundamental division of the genus into three clades, only one of which contains both Asian and North American species. Second, the widespread and polymorphic Asian species, G. japonica, is sister to the two North American species, G. triacanthos and G. aquatica, which themselves are closely related inter se, but are both polymorphic and paraphyletic. Third, the lone South American Gleditsia species, G. amorphoides, forms a clade with two eastern Asian species. Gleditsia thus appears to have only one Asian-North American disjunction and no intercontinental species pairs. Low sequence divergence between G. amorphoides and its closest Asian relatives implicates long-distance dispersal in the origin of this unusual disjunction. Sequence divergence between Asian and North American Gleditsia is much lower than between Asian and North American species of its closest relative, Gymnocladus. Estimates of Asian-North American divergence times for Gymnocladus are in general accordance with fossil data, but estimates for Gleditsia suggest recent divergences that conflict with ages of known North American Gleditsia fossils.

Summary The evolution of self‐pollination has long been considered an adaptive strategy to cope with low or variable pollinator service; however, alternative reproductive strategies, such as generalized pollination (>1 pollinator functional group), may also ensure plant reproductive success in environments with inadequate pollinator visitation. Island–mainland systems provide ideal settings to assess the interaction between pollination and breeding systems in response to pollinator visitation because islands are often pollinator‐depauperate. This study compared 28 insular and 26 mainland species of Caribbean Gesneriaceae to test the hypothesis that low diversity and possibly low pollinator service on islands would lead to a greater frequency of generalized plant–pollinator interactions and/or a higher potential for autonomous self‐pollination in insular than in mainland species. We also assessed the hypothesis that epiphytic species should have greater autofertility than species occurring in other habitats. Pollinator observations conducted in the field from 2004 to 2014 revealed bat, bee, butterfly, hummingbird, moth, and generalized pollination systems. Functional specialization in pollination systems was high in insular (71% of the species) and mainland sites (all species), but generalized and bat‐pollinated species were more common on islands. Overall, pollinator visitation rates did not differ between island and mainland; however, for hummingbird‐pollinated species, visitation rate was on average three times higher in mainland than island species. Autofertility indices (fruit set of bagged/outcross flowers) ranged from 0 to 1 and did not differ between island and mainland species. Species growing on rocks (rupiculous) and trees (epiphytic) had on average higher autofertility than terrestrial species. Synthesis. This study revealed that alternative reproductive strategies are used in pollinator‐depauperate environments. Pollinator visitation is lower in insular hummingbird‐pollinated species (the ancestral pollination system of insular Gesneriaceae); therefore, generalized pollination may be considered a reproductive assurance mechanism evolved primarily on island environments. Contrary to the long‐standing tenet, however, autonomous self‐pollination was similar in island and mainland Gesneriaceae suggesting that: (i) generalized pollination provides a viable alternative to selfing in pollinator‐depauperate environments, (ii) autofertility as a reproductive assurance mechanism may be frequent in plant species from mainland regions in environments with unpredictable pollinator visitation and resource availability.

Ocotea porosa has been extensively exploited over the past few decades because of the quality of its wood. Today, populations are reduced and the species is now included in the Red List of threatened species by the International Union for Nature Conservation. For conservation and management purposes, it is extremely important that we understand its reproductive ecology. Floral morphology was described based on field and scanning electron microscopic examination. The reproductive system was determined through experimentally controlled pollination along with observations of pollen tube growth. Pollinators were identified through field observations. Flowers of O. porosa are small, shallow, inconspicuous, asynchronous and grouped in inflorescences. This species presented self‐compatibility, but did not reproduce through apomixy and spontaneous self‐pollination was very rare (5%). Despite being monoclinal, flowers were protogynic, and the gynoecium was receptive after the first day of anthesis when the anthers were closed. Spontaneous self‐pollination was avoided by the extrorse position of the anthers of the internal stamens. Frankliniella gardeniae (Thysanoptera) was the only pollinating species observed and, after visiting several asynchronous flowers in the same inflorescence, favors geitonogamy. Together the small distance supposedly achieved by thrips in flight and the small population density of O. porosa can reduce the chances of cross‐pollination in this species. If so, conservation measures must include preservation of the current population and possibly planting to increase population density. This would reduce the distance between individuals and increase genetic variability. Thrips as pollinators must be included in conservation planning for O. porosa .

Reproductive biology is an important topic that is well explored in many vertebrates, but information about frogs’ reproductive mechanisms could be improved. Therefore, this review aims to provide organized and specific information on frog reproduction. First, we developed schemes that illustrate the general information regarding reproductive biological mechanisms in frogs in a specific way. Then, we described the physiological, histological, and morphological mechanisms of each organ of the reproductive system of male and female frogs. Finally, this manuscript may contribute to a broader understanding of anuran reproductive biology. Since, understanding frogs’ reproductive system permits one to make a comparison with reproduction with other anurans.

The campo rupestre is a Neotropical OCBIL (old, climatically buffered infertile landscape), a grassy-shrub vegetation with high species richness and endemism, characterized by rocky outcrops surrounded by grasslands distributed in South American ancient mountaintops. We tested one OCBIL prediction: the prevalence of long-distance pollinators ensuring cross-pollination across the archipelago-like landscapes of the campo rupestre. We described the pollination systems and tested whether their frequency differed across vegetation types and elevation, focusing on long-distance systems. We performed non-systematic and systematic surveys of plants and plant-pollinator interactions across the elevation gradient and vegetation types. We also reviewed the literature on campo rupestre pollination and applied an accuracy criterion to infer 11 pollination systems. The bee system was split into large bee (long-distance) and small bee (shorter distances) to test the prevalence of long-distance pollination systems. We surveyed 413 pollinator species, mostly bees (220) and flies (69). Among the 636 plant species studied, the bee pollination system was dominant (56%), followed by wind and hummingbird. Wind, small-bee and fly pollination systems increased with elevation, and small-bee and wind pollination systems prevailed in grasslands. Large-bee and hummingbird long-distance pollination systems remained unchanged with elevation and were more frequent in the highly isolated rocky outcrops corroborating the OCBIL theory.

Evolutionary breakdown from rigorous outbreeding to self-fertilization frequently occurs in angiosperms. Since the pollinators are not necessary, self-compatible populations often reduce investment in floral display characteristics and pollination reward. Primula forbesii is a biennial herb with distribution restricted to southwest China; it was initially a self-incompatible distylous species, but after 20 years of artificial domestication, homostyly appeared. This change in style provides an ideal material to explore the time required for plant mating systems to adapt to new environmental changes and test whether flower attraction has reduced following transitions to selfing. We did a survey in wild populations of P. forbesii where its seeds were originally collected 20 years ago and recorded the floral morph frequencies and morphologies. The floral morphologies, self-incompatibility, floral scent, and pollinator visitation between distyly and homostyly were compared in greenhouse. Floral morph frequencies of wild populations did not change, while the cultivated population was inclined to L-morph and produced homostyly. Evidence from stigma papillae and pollen size supports the hypothesis that the homostyly possibly originated from mutations of large effect genes in distylous linkage region. Transitions to self-compatible homostyly are accompanied by smaller corolla size, lower amounts of terpenoids, especially linalool and higher amounts of fatty acid derivatives. The main pollinators in the greenhouse were short-tongued Apis cerana. However, homostyly had reduced visiting frequency. The mating system of P. forbesii changed rapidly in just about 20 years of domestication, and our findings confirm the hypothesis that the transition to selfing is accompanied by decreased flower attraction.

Govocitos is a multi-platform application designed to integrate all processes to estimate the fecundity of fish, a fundamental issue for the management of sustainable fisheries. Govocitos incorporates supervised and unsupervised algorithms to extract oocytes and their features in digitized histological images. Oocytes are classified automatically into the classes used traditionally in studies of reproductive ecology. A database gives support to allow for reproducible data management and to share results among different laboratories. The output of Govocitos has been evaluated through extensive validation procedures and found to be precise and accurate. Govocitos is open source software running on Linux and Windows platforms.

Fertility and fecundity are related terms: fecundity refers to the biological capacity or potential for reproduction, while fertility refers to the actual production of live offspring. Biological fecundity is a necessary precondition for fertility, but a wide array of influences of environment and of individual behavior modify that potential and shape achieved fertility. Human populations vary greatly in both the level and timing of fertility. Much of this variation can be understood in terms of pathways linking patterns of behavior and environmental conditions to reproductive physiology, especially ovarian function, through the study of reproductive ecology. Evolutionary theory, especially life‐history theory, provides a basis for an integrated understanding of the biological aspects of reproduction and their relationship to the social and biophysical environments.

To understand the relationships between floral morphologies and the reproductive strategies of plants, the contributions of multiple pollinators to plant reproductive success need to be examined. To outline recent advances on this topic, we review studies of five bumblebee‐pollinated plants in Japan. These plant species are pollinated by one to three bumblebee species differing in proboscis length: Bombus consobrinus, Bombus diversus and Bombus honshuensis. These pollination systems allow us to compare the reproductive strategies of plants pollinated by single and multiple bumblebee species. First, we address the effects of morphological correspondence between flowers and pollinators on the reproductive success of plants. In plants with narrow tubular flowers, Isodon umbrosus and Clematis stans, pollination effectiveness depended on the morphological correspondence between floral tube length and pollinator mouthparts. These flowers are subject to varied directions and intensities of selection by multiple bumblebee species, resulting in the maintenance of large variation in floral morphology within and between populations, and even within individuals. In contrast, pollination effectiveness in plants having flowers with a wide entrance, Melampyrum roseum and Hosta sieboldiana, did not differ among bumblebee species because of good correspondence between floral morphology and bumblebee body size, resulting in small morphological variations among flowers. Thus, generalized pollination systems with multiple pollinator species favor floral traits that enable the use of various pollinators. Second, we address the quantity and quality of the pollination service in bumblebee‐pollinated plants. Isodon umbrosus, with its generalized pollination system, suffered from pollen limitation because of low pollination quality. In contrast, Isodon effusus, which has a specialized pollination system, suffered from pollen limitation because of low pollination quantity. Isodon umbrosus produced large numbers of short tubular flowers to improve pollination quantity, whereas I. effusus produced small numbers of long tubular flowers to improve pollination quality, resulting in a clear trade‐off between the size and number of flowers within plants. In M. roseum, which has a generalized pollination system, three bumblebee species achieved sufficient pollination, but seed production was limited by an increased rate of self‐pollination. This is because this species invests more resources in cross‐pollinated seeds by selective abortion of selfed seeds. Our results demonstrate that the strategy of generalized plants is to improve pollination quantity, whereas the strategy of specialized plants is to improve pollination quality.

Pollination and breeding systems of woody plant species in tropical dry evergreen forests, southern India

The physical locations of 5S and 18S-25S rDNA sequences in 15 diploid Hordeum species with the I genome were examined by double-target in situ hybridization with pTa71 (18S-25S rDNA) and pTa794 (5S rDNA) clones as probes. All the three Asian species had a species-specific rDNA pattern. In 12 American species studied, eight different rDNA types were found. The type reported previously in H. chilense (the 'chilense' type) was observed in eight American species. The chilense type had double 5S rDNA sites - two sites on one chromosome arm separated by a short distance - and two pairs of major 18S-25S rDNA sites on two pairs of satellite chromosomes. The other seven types found in American species were similar to the chilense type and could be derived from the chilense type through deletion, reduction or addition of a rDNA site. Intraspecific polymorphisms were observed in three American species. The overall similarity in rDNA patterns among American species indicates the close relationships between North and South American species and their derivation from a single ancestral source. The differences in the distribution patterns of 5S and 18S-25S rDNA between Asian and American species suggest differentiation between the I genomes of Asian and American species. The 5S and 18S-25S rDNA sites are useful chromosome markers for delimiting Asian species, but have limited value as a taxonomic character in American species. On the basis of rDNA patterns, karyotype evolution and phylogeny of the I-genome diploid species are discussed.

 The Annonaceae is a large, early-divergent family of angiosperms. Although the majority is pollinated by small beetles, there is a great diversity of floral morphologies. Evolutionary shifts of pollination mechanisms have occasionally been reported in disparate lineages including shifts to pollination by large beetles, flies, thrips, bees and cockroaches. It was previously hypothesized that floral morphological changes in different lineages are adaptive and correspond to evolutionary shifts of pollination mechanisms. This hypothesis is tested here by comparing selected species that have substantial morphological differences with their close relatives. \n\n Comprehensive studies of the floral biology of four Annonaceae species, Dasymaschalon trichophorum, Desmos chinensis, Pseuduvaria mulgraveana and Uvaria cordata, are presented. All are beetle-pollinated. Dasymaschalon trichophorum, D. chinensis and U. cordata were inferred to be self-compatible based on inter-simple sequence repeat marker data as there was evidence of significant gene flow and a low level of genetic differentiation between populations. This was corroborated for D. chinensis and U. cordata by experimental controlled pollination tests for geitonogamy, in which both were shown to set fruit.\n\n Similar floral phenological and pollination ecological results were obtained for D. chinensis and D. trichophorum despite significant differences in floral architecture, as the former has six petals (typical of most other Annonaceae species), whilst the latter only has three. The results suggested that the substantial change in floral morphology in these two closely-related genera is probably non-adaptive as there is no change in pollination system. It is hypothesised that the morphological change is likely due to the disruption of homeotic gene expression during floral organ development. \n\n Studies of floral phenology and pollination ecology of Uvaria cordata revealed that it has a 3-day flowering rhythm and is pollinated by small beetles. The pollination ecology is unexpectedly similar to other species with typical beetle-pollination syndromes, although it lacks a pollination chamber and has pale-colored petals. It is suggested that species that lack a pollination chamber are more likely to be pollinated by guilds other than beetles or thrips as a floral chamber increases pollinator specificity. Several morphological and phenological characters are also presumably correlated with the evolution of generalist pollination to increase the pollination efficiency and assure fruit production, including torus shape, petal orientation, stigma shape, petal color, carpel and/or ovule number and the overlap of pistillate and staminate phases. \n\n Pseuduvaria is unusual in the Annonaceae as the majority of species possess unisexual flowers. Most species were previously interpreted as having staminate and structurally pistillate flowers, with infertile staminodes in the latter. The ‘pistillate’ flowers of P. mulgraveana are shown to produce viable pollen, however, contradicting this hypothesis. It is therefore recommended that floral unisexuality in the genus be reassessed by testing more species from different clades. \n\n Different strategies to promote xenogamy in the Annonaceae are reviewed, including protogyny, herkogamy, intra- and inter-individual phenological synchrony and dioecy. Three different mechanisms were recognized to achieve dioecy, including incomplete pollen development in hermaphroditic flowers, delayed anther dehiscence in hermaphroditic flowers and loss of androecium or gynoecium (with Pseuduvaria used as a paradigm).