山茶科濒危植物猪血木的花器官发生

利用扫描电镜首次观察了山茶科极濒危植物猪血木(Euryodendron excelsum)的花器官发生过程。猪血木的花为两性完全花,萼片和花瓣均为2/5螺旋向心发生,单轮排列,且有逆时针和顺时针两种方式。雄蕊的形成是先形成一个环形分生组织,然后在环形分生组织上以2/5螺旋产生5束雄蕊原基,每一束雄蕊原基的第一雄蕊原基都是在对萼的位置产生,其它的雄蕊原基在其两侧产生。3心皮顺序发生,愈合成3室单子房,柱头平截不裂。猪血木与山茶亚科的花器官发生明显不同。

Early Floral Development of Endangered Euryodendron excelsum (Ternstroemioideae : Theaceae)

The floral development of a critically endangered plant Euryodendron excelsum from Ternstroemioideae (Theaceae) has been observed under scanning electron microscope (SEM) for the first time. The flower of E.excelsum is bisexual and teleianthous. Five sepal primordia are initiated 2/5 spirally and arranged in one whorl when mature, and so are petals. Sepals and petals are initiated in the same order either clockwise or counterclockwise in the same flower. The androecial part is a ring primordium in the beginning. The first five stamen primordia are initiated on this ring primordium at antisepalous positions and then other stamen primordia appear on two sides of each of the first five primordia. Finally a total of 25 stamen primordia are initiated from the ring primordium and arranged in one whorl but could be grouped into 5 fascicles. Three sequentially initiated carpels compose an ovary which has an axile-central placenta with three locules and a truncate and indehiscent stigma. The floral development of E.excelsum is distinctly different from plants in Theoideae.