蓖麻的花部發育

Abstract

藉由掃描式電子顯微鏡檢及光學顯微鏡檢研究大戟科的植物蓖麻的花部發育，發現其花序是由二出聚繖花序為一小單位，排列成一穗狀花序。花部發育的初期是相同的，當花萼形成後，雌、雄花的發育開始出現差異，雌花的雌蕊始原發育成具有三癒合心皮、三花柱和六柱頭的雌蕊，雄花的雄蕊始原發育成多數的雄蕊及多分枝的花絲。雌花發育的初期在花萼及雌蕊間出現一些特殊的構造，其中有些是似雄蕊的，其隨著雌花的發育而發育，並且具有不同的形式及數目。似雄蕊構造的花粉形式和正常雄蕊的花粉均為三溝孔，但其直徑較小，且經花粉活性測試其不具活性。

In Taiwan, Ricinus communis L. is a cultivated and naturalized plant of Euphorbiaceae, with a complex inflorescence. This monoecious plant has female flowers on the upper part of the inflorescence and male flowers on the lower. The spike of the inflorescence consists of dichasia. The early development of both female and male flowers are similar, however they differentiate after initiation of gynoecium and androecium primordia. We observed some unusual structures within the female flowers in this monoecious plant. These tiny structures initiate and grow around the base of ovary and they are variable in shape and size. Some stamen-like structures were recognizable when the gynoecium differentiated into stigma, style and ovary. These staminodes were examined and compared with the stamens in male flowers by using electron microscopy and light micorscopy.