三粒小麦额外雌蕊的分化

Differentiation of Additional Pistils in A Trigrain Wheat

用扫描电镜和石蜡切片方法观察了三粒小麦花和3个雌蕊的分化.看到花分化的前期和普通小麦完全相同,但在形成雄蕊原基、雌蕊原基及浆片之后,并不就此终止分化,而是由浆片腋部的亚下皮层细胞进行平周分裂形成两个额外的副雌蕊,其发生类似芽的起源,副雌蕊也是小花中最晚分化的结构.从起源上看,副雌蕊不仅有别于由小花顶端分生组织转化而成的主雌蕊,高且也不是心皮化的结果.副雌蕊虽最晚发生,但在花柱形成后却发育迅速,得以在开花时达到成熟,和主雌蕊一样具有正常的可育性.

The differentiation process of florets and the three pistils of a trigrainwheat is investigated with a scanning electronic microscope and paraffinsection method.It is observed that the differentiation process of florets ina trigrain wheat is just the same as in common wheat,but after the formationof lodicules and primordia of stamen and pistil,floret differentiation doesnot stop and other two additional pistils are gradually formed by periclinaldivision of sub-hypodermal cell in the axil of lodicules.The productivemanner of the additional pistils which differentiate at the latest in floret,is analogous to that of a bud.According to their origin,the additional pistils are not only differentfrom the primary pistil,which comes from meristem tissue at the top of thefloret,but also without carpellody in constitution.Though the additionalpistils occur late,they develop quickly after style-formation so that theyachieve maturity and get normal fertility as the primary pistil does duringthe blooming.