润楠雄配子体发育的超微结构研究 Ⅲ.营养细胞和生殖细胞的形成

对润楠(Machilus pingii Cheng ex Yang)花粉生殖细胞和营养细胞的形成进行了观察.结果如下:(1)随着小孢子核向(?)方向迁移,胞质的线粒体和前质体显著增多;由于大液泡的存在,细胞器偏向核的一侧分布.(2)小孢子有丝分裂末期,胞质中出现较多的高尔基体和微管.(3)生殖细胞(?)抵达花粉内壁后,生殖细胞和营养细胞的胞质中出现大量与壁平行排列的粗面内质网.随着生殖细胞壁的加厚, 生殖细胞的局部与营养细胞核相贴近,贴近区域的生殖细胞质中出现交织成网的内质网.(4)游离的生殖细胞具,胞质中仅有少量细胞器;营养细(?)中储存有大量的淀粉粒.从观察结果推测:影响润楠生殖细胞在花粉内进一步分裂的因素可能有三种:一是生殖细胞壁留存的时间;二是营养细胞和生殖细胞本身的代谢状况;三是营养细胞核对生殖细胞的作用.

FINE-STRUCTURAI STUDY ON THE DEVELOPMENT OF MALE GAMETOPHYTE IN MACHILUS PINGII CHENG EX YANG (LAURACEAE)III. THE FORMATION OF GENERATIVE AND VEGETATIVE CELLS

The Present PaPer deals Wrth the formatron of the generative and vegetative cells of male gametophyte in Machilus pingii Cheng ex Yang. The main results are summarized as follows: (1) As the microspore nucleus is displaced from the centre toward one side of the cell, the cell organelles show marked Polarisation.Most of the mitochondria and plastids arc found around the microspore nucleus.(2) There is a dramatic increase in the number of dictyosomes and microtubules in the further development.(3) After the fan-shaped celt plats gives rise to the pollen intine, numerous well developed rERs in both generative cell wall. As development proceeds, the part of the generative cell gets in touch with the vegetative cell nucleus. In ths region, the endoplasmic rsticulum of teh generative cell appsars a network system.(4) When the generative cell becomes round and free in ths cytoplasm of the vegetative cell, the generative cell has a few organelles and vegetative cell has numerous starch grains. The variation of the vegetative cell organelles and the generative and the factors to influence further division of the generative cell are discussed.