观光木的花器官发生

Floral organogenesis of Tsoongiodendron odorum Chun

摘要:

在扫描电镜下观察了观光木 (Tsoongiodendron odorum Chun) 的花器官发生发育。观光木的花原基最初为近圆形，随着顶端分生组织的活动，花原基边缘处出现浅凹，形成第一轮花被片原基，此时，花原基呈三角形排列，后两轮花被片原基依次发生，与前一轮互生；在内轮花被片发生的后期，最初几枚雄蕊原基几乎同时出现，呈螺旋状向顶发生，最后排列成三角圆锥状；雄蕊原基发育后期，心皮原基开始发育，形状与发育初期的雄蕊原基相似，随后心皮原基进行侧向生长，在近轴面出现浅凹，进而发育为凹槽，形成腹缝线，最后腹缝线完全愈合。腹缝线愈合现象表明观光木具有进化特征，与含笑属的亲缘关系较近。

Abstract:

The floral organogenesis of Tsoongiodendron odorum Chun was observed under scanning electron microscope (SEM). The floral primordium is initially circular, along with the edge of which slight concaves occur. The outmost whorl of tepal primordia arises as a result of apical meristem division and the floral primordium then is in the shape of triangle. Two further whorls of tepal primordia arise in spiral acropetal sequence and are alternately arranged. When the innermost whorl of tepal primordia is at the late developmental stage, the foremost stamen primordia arise almost simultaneously in spiral acropetal succession and all of the stamen primordia are ultimately arranged in a triangle-cone form. Late in stamen primordium development, carpel primordia arise as same as the young stamen primordia and grow laterally. Grooves are present on the adaxial side of each carpel and develop into ventral sutures gradually closing up. Concrescence of ventral sutures indicates that T. odorum with advanced characteristics is close to Michelia L..