An Examination of the Function of Male Flowers in an Andromonoecious Shrub Capparis spinosa  

作　　者：Tao Zhang Dun-Yan Tan 

机构地区：[1]Xinjiang Key Laboratory of Grassland Resources and Ecology, College of Grassland and Environment Sciences, Xinjiang Agricultural University, Orümqi 830052, China [2]Xinjiang Institute of Materia Medica, Orümqi 830002, China

出　　处：《Journal of Integrative Plant Biology》2009年第3期316-324,共9页植物学报（英文版）

基　　金：Supported by the Projects on the Research and Development of High Technology of Xinjiang Uygur Autonomous Region (200810102), China, the Construction of Scientific and Technological Platforms Project from the Chinese Ministry of Science and Technology (2005DKA21006 and 2005DKA21403);the National Natural Science Foundation of China (90302004).

摘　　要：The pollen donor and pollinator attractor hypotheses are explanations for the functions of the male flowers of andromonoecious plants. We tested these two hypotheses in the andromonoecious shrub Capparis spinosa L. （Capparaceae） and confirmed that pollen production and cumulative volume and sugar concentration of nectar do not differ between male and perfect flowers. However, male flowers produced larger anthers, larger pollen grains and smaller ovaries than perfect flowers. Observations on pollinators indicated that two major pollinators （Xylocopa valga Gerst and Proxylocopa sinensis Wu） did not discriminate between flower morphs and that they transferred pollen grains a similar distance. However, there were more seeds per fruit following hand pollination with pollen from male flowers than from perfect flowers. Individuals of C. spinosa with a larger floral display （i.e. bearing more flowers） received more pollen grains on the stigma of perfect flowers. Female reproductive success probably is not limited by pollen. These results indicate that male flowers of C. spinosa save resources for female function and that they primarily serve to attract pollinators as pollen donors.The pollen donor and pollinator attractor hypotheses are explanations for the functions of the male flowers of andromonoecious plants. We tested these two hypotheses in the andromonoecious shrub Capparis spinosa L. （Capparaceae） and confirmed that pollen production and cumulative volume and sugar concentration of nectar do not differ between male and perfect flowers. However, male flowers produced larger anthers, larger pollen grains and smaller ovaries than perfect flowers. Observations on pollinators indicated that two major pollinators （Xylocopa valga Gerst and Proxylocopa sinensis Wu） did not discriminate between flower morphs and that they transferred pollen grains a similar distance. However, there were more seeds per fruit following hand pollination with pollen from male flowers than from perfect flowers. Individuals of C. spinosa with a larger floral display （i.e. bearing more flowers） received more pollen grains on the stigma of perfect flowers. Female reproductive success probably is not limited by pollen. These results indicate that male flowers of C. spinosa save resources for female function and that they primarily serve to attract pollinators as pollen donors.

关 键 词：ANDROMONOECY Capparis spinosa pollen donor pollinator attractors reproductive success. 

分 类 号：S651[农业科学—果树学] S793.9[农业科学—园艺学]