摘要
雌雄同株榕树Ficus具有显著的雌花花柱异长现象并在花序腔内形成子房的不同层次的空间结构。在每个子房层里的每一朵雌花都可能产生一个种子或是一个小蜂后代。研究针对雌雄同株的子房分层现象,对榕亚属的垂叶榕F.benjaminasubgenusUrostigma从雌花期到雄花期进行了跟踪调查。该种榕树雌花期的花序果可接收多于一只传粉小蜂E.koningsbergeri,说明小蜂间存在产卵竞争。雄花期产蜂雌花的子房层分布显示,在雌花期传粉小蜂间有产卵竞争的情况下,它们多将卵产在中间层的子房中。这一现象说明,小蜂间为竞争产卵位置使其有增加在外层子房中产卵的趋势。同时,对雄花期产种子的雌花子房分布调查表明,产种子的雌花花柱显著长于产蜂的雌花,即明显向子房外层分布方向增加。另外,还发现在少数果中只有种子产生。与正常即产种子又产小蜂的花序果相比,在短花柱雌花的子房中产生的种子明显增加,这些种子多集中于中层子房花中。雄花期调查结果还表明,最终种子的产出显著大于传粉小蜂后代的产出,表现出明显的种子产出优势。产蜂与产种子的子房的空间分层分布与榕树雄花期的种子和小蜂产出之间的差异均表明,榕树的雌花子房分层现象是调节榕树与传粉小蜂利益冲突的关键因素。榕树具有明显的种子优势可能也与雌花的子房分层有关。
In monoecious figs, ovaries of female flowers are stratificated with different style lengths. Each female flower can produce either a seed or a wasp offspring. According to this, Ficus benjamina subgenera Urostigma was investigated at different flower phase. Results showed that there was more than one foundress in the receptive syconium at B phase which had successfully oviposited and pollinated, which indicated strong competition among pollinating wasps. Frequency of styles of female flowers producing pollinating wasps showed that, when with foundress competition, pollinating wasps preferred to oviposit in the midst layer of ovaries. Different style lengths between flowers near to the wall and near to the cavity indicated that competition made pollinating wasps deposit more of their eggs in ovaries near to the wall. Styles of female flowers producing seeds were significantly longer than that of flowers producing pollinating wasps. Seeds could be produced in different layers of ovaries but mostly be produced in ovaries near to the fig wall. In our observations, there are some figs producing only seeds without any wasps. Seeds in these'only_seed_figs'were mostly produced in shorter_styled flowers. Besides, production of seeds at D phase was significantly more than that of wasps, which showed an obvious advantage of figs (and/or seeds). According to the difference between styles of flowers producing seeds and wasps and between the production of seeds and wasps, heterostyly may be the crucial factor regulating the conflict of interest between figs and their pollinating wasps.
出处
《中山大学学报（自然科学版）》
CAS
CSCD
北大核心
2005年第B06期271-274,共4页
Acta Scientiarum Naturalium Universitatis Sunyatseni
基金
中国科学院知识创新工程重要方向性基金资助项目(KSCX2-SW-105)
关键词
垂叶榕
传粉小蜂
雌花子房分层
繁殖利益冲突
Ficus benjamina
pollinating wasp
stratification of ovaries
conflict of interest
