中国鹅掌楸雄性生殖单位的二维结构

中国鹅掌楸花粉属二细胞型，观察了６枚在异己－北美鹅掌楸柱头沟中的花粉管。在花粉管进入柱头沟时，管长为花粉直径的４－１０倍期间，生殖细胞分裂形成两精细胞，同一花粉管的两精子在大小、形态上有明显差异、精子两形，两精细胞相互邻接，位于管的先端，两精子被营养细胞内质膜包围，大的精细胞通过细胞延伸乌黑营养核，同时部分地被营养核的裂片所包围，两精子和营养核形成的共同包装即为雄性生殖单位。败育花粉管中，精细胞几

DIMENSIONAL FEATURES OF MALE GERM UNIT IN LIRIODENDRON CHINENSE SARG.

s:The pollen of Liriodendron chinense is of two-cell type.The six pollen tubes located at the stigma chord of alien-L.tulipifera wer observed with electron microscope.When the pollen tube extended to the stigma chord,and the length of the pollen tube was 4-10 times as the diameter of pollen, the generative cell split into two sperms.The two sperms of a given pollen tube were different in size and morphology,namely sperm heteromorphism.Sperm-to-sperm connection was near the pollen tube tip.The sperms were also encompassed by the inner vegetative cell plasma membrane,and one sperm(Svn)was consistently associated with the vegetative nucleus through a sperm cell extension that embraces the vegetative nucleus and was partially surrounded by lobes of the vegetative nucleus.The sperm cell-vegetative nucleus packaging is called Male Germ Unit.When pollen tube degenerated,the sperm cell did not extend and the packaging of sperm cell-vegetative nucleus did not result.