橡胶树花药和小孢子发生与发育过程的观察

OBSERVATION ON THE DEVELOPMENT OF ANTHER AND MICROSPORE IN HEVEA BRASILIENSIS

应用石蜡切片法,观察橡胶树的实生树和RRIM600、CT-1品系的花药壁以及小孢子的发生和发育过程,得到如下结果:1.实生树的花药壁通常由四层细胞组成,发育形式为双子叶型。药室内壁细胞在发育后期进行径向条纹加厚,至花药开裂时仍保留着原生质体。中层由一层或不规则的两层细胞组成,在小孢子单核期消失。绒毡层细胞具单核或双核,属分泌型,至花粉发育到三细胞时消失。小孢子母细胞减数分裂为同时型。成熟花粉粒具三个细胞。精细胞椭圆形,在光镜下不能区分出细胞质鞘和核仁。所观察的实生树雄花,多数发育正常,很少有空秕的花粉。2·RRIM600品系的花药和小孢子发生与发育和实生树相似,但至后期只有少数花粉发育正常,多数成为大小不等的败育花粉;此外也有一些败有的雄花。3.GT-1的花药在小孢子母细胞减数分裂时,绒毡层细胞的体积开始异常增大并液泡化,小孢子在四分体内解体或分离后成为空秕花粉。

The development of anther and microspore in Hevea seedling and in Hevea clones RRIM 600 and GT-1 were observed, and the results are as follows: 1. Anther wall of seedling tree consists of four layers of cells and its formation is of dicotyledonous type. In later development stages some fibrous thickenings appear on the walls of endothecium cells,in which the protoplast remains until anther dehiscence. The middle layer consists of one layer of cells or two layers of irregular cells and disappears in monokaryon stage. Tapetal cells being of secretory type have one or two nuclei and disappear in 3-celled stage. Meiosis of microspore mother cell is of simultaneous type. The mature pollen comprises three cells, among them the sperm cells are spherical in shape and the cy-toplasmic sheath and nucleolus are unable to be recognized under light microscope. 2. In RRIM600 the development of microspore is similar to that in the seedling tree, but in the later stage most of them become aborted pollens with different sizes and only a few grow normally; besides, some flowers degenerate entirely. 3. For GT-1, in the meiosis stage of microspore mother cell, the tapetal cells become peculiarly enlarged and vacuoled, as the result, the microspores disintegrate inside the tetrad or segregate into empty pollens.