糜子绒毡层及雄配子体的超微结构

单核花粉时期，细胞质中含有粗糙内质网、线粒体、质体等；小泡时期、细胞质中含丰富的粗糙内质网，且小泡聚合成大液泡，有丝分裂前的小泡子外壁已发育，内壁开始沉积。小孢子第１次有丝分裂完成后、在营养核与生殖核之间有１弧形细胞壁。初期的生殖细胞和营养细胞的细胞质中、细胞器是没有差别的，当生殖细胞发育至游离的裸细胞时，生殖细胞中质体不发育或退化，相反，营养细胞中的质体和线粒体在数量和大小上增加、在质体中积累淀粉。精细胞由椭圆形最后变为具尾延长的细胞，细胞质集中到尾部。绒毡层为腺质。单核花粉初期，绒毡层细胞质中富含粗糙内质网、质体、小泡、线粒体及高尔基体；最后，绒毡层细胞开始退化、绒毡层解体后，退化的细胞质流入花药腔中、内含乌氏体、脂滴等。

Ultrastructure of Tapetum and Male Gametophyte in Panicum miliaceum

In the stage of uninuclear microspore,there are rough endoplasmic reticulums,mi-tochondron and plastids in the cytoplasm.In the vaculoes stage of uninuclear microspore,there areabundent rough endoplasmic reticulums in the cytoplasm.Small vacuoles begin to fuse to large vac-uole.Before the mitosis of the uninuclear microspore,the exine begins to develop and the intine beginsto sediment.After the mitosis of the microspore cell wall appears between the generative and vegetative nucle-us. In early developmental stage of male gametophyte, the organelles in the cytoplasms of the genera-tive cell and the vegetative cell are simiar.When the generative cell became naked and free in the cytoplasm of the vegetative cell, the or-ganelles in the cytoplasm of the generative cell had little changes besides the degeneration of plastid. Inthe vegetative cytoplasm the mitochondria and plastids increased dramdatically both in number andsize. Rapid deposition of starch in the plastids of the cytoplasm of the vegetative cell accured.In early stage the shape of sperm cell is ellipfical.Finally it forms an elongated cell with a tail-like structure. The distribution of cytoplasm gradually concentrated at one end of the sperm cell.The tapetum is secretory type. In early developmental stage of uninuclear microspore,there arein rough endoplasmic reticulum. platsidsane mitochondria,Small vacuoles and dictyosomes appear inthe cytoplasm of tapetum.Finally the tapetum degenereted completelly,The cytoplasm with lipidbodies,Ubish bodies and orbicules flows into the anther lumen