水筛的花器官发生

Floral Organogenesis of Blyxa japonica (Hydrocharitaceae)

摘要:

利用扫描电镜首次对水筛[Blyxa japonica（Miq.）.Maxim.ex Asch.et Cürk.]花器官的发生进行了观察。结果显示:萼片原基以轮状方式向心发生;花瓣原基轮状近同时发生,与萼片原基交替排列:雄蕊原基以对萼的形式轮状发生,与花瓣原基交替排列:花柱原基在整个花的发育过程中发生较晚,以对瓣的形式轮状发生,与雄蕊原基交替排列。与同科其它属的花比较,水筛的花为两性,辐射对称,胚珠多数,体现了较原始的特征。花各部数目均为3,进化程度居于中间水平。该属化各部轮状发生,子房下位,心皮合生,体现了本科在泽泻亚纲中花部结构进化的特征。

Abstract:

Floral development of Blyxa japonica (Miq)Maxim, ex Asch. et Gürk(Hydorcharitaceae) has been observed under scanning electron microscope (SEM). The sepal primordia first initiate on radii verticillately. A whorl of alternisepalous petal primordia forms nearly simultaneously. Three antisepalous stamen primordia initiate verticillately, alternating with petal primordia. At the base of petal primordia, three antipetalous gynoecial primordia appear verticillately. Compared with other genera in the family, the flower of Blyxa japonica shows many primitive characteristics，such as bisexual，actinomorphic an d numerous ovules，whereas the number of floral organs is fixed as 3 shows its interm ediate evolutionary leve1． Floral organongensis initiating verticillately and inferior ovary indicate advanced characteristics of Hydrocharitaceae in Alismatidae.