采用常规石蜡切片法对光皮树〔Swida wilsoniana ( Wanger.) Soják.〕花芽分化过程中的解剖学特征进行了研究,并对花芽的外部形态也进行了观察。 结果表明,光皮树的顶芽和腋芽都可以进行花芽分化;花芽分化在 2 月下旬开始,4 月底基本完成;整个花芽分化过程可划分为 5 个时期:花芽未分化期、花序分化期、花萼分化期、花瓣分化期和雌雄蕊分化期,其中花序分化期还可分为分化前期和分化后期。 在花芽分化过程中,光皮树的花芽形态逐渐增大、饱满,径向和纵向伸长,并在花瓣分化期形成塔形聚伞状花序。 花芽纵切面的解剖结构显示,在花芽分化过程中,花芽内的生长锥逐渐增大并向上隆起;在花萼分化期生长锥的边缘产生 4 个萼片原基;在花瓣分化期花萼原基内侧分化出花瓣原基,并与花萼原基交互而生;雌雄蕊分化期在花瓣原基的内侧分化出雄蕊原基,同时在生长锥中心形成雌蕊的心皮原基。 经过一系列的生长分化过程最终形成光皮树的花萼、花瓣及雌蕊和雄蕊。

 

The anatomical characteristics of Swida wilsoniana ( Wanger.) Soják. flower bud during differentiation process were studied by paraffin method, and the external morphology of flower bud was also observed. The results show that both terminal bud and axillary bud of S. wilsoniana can differentiate into flower bud. The differentiation starts at late February and ends around the end of April. The whole differentiation process may be divided into five stages, including flower bud undifferentiation stage, inflorescence differentiation stage, calyx differentiation stage, petal differentiation stage, pistil and stamen differentiation stage, in which the inflorescence differentiation stage can be divided into prophase and anaphase. In the flower bud differentiation process, the flower buds of S. wilsoniana gradually grow larger, and extend longitudinally and radially. Pyramidal cymes are initiated in petal differentiation stage. According to the longitudinal section of flower bud, in flower bud differentiation process, growing tip in the bud grows bigger and protrudes upward. Four calyx primordia arise around the growing tip in calyx differentiation stage. Petal primordia are initiated inside calyx primordia and alternately spaced with calyx primerdia in petal differentiation stage. Stamen primordia appear inside petal primordia in pistil and stamen differentiation stage and meanwhile carpel primordia of pistil are initiated in the center of growing tip. These primordia develop into calyx, petal, pistil and stamen after growth and differentiation.