OBJECTIVETo study the characteristics of male sterility of Bupleurum chinense and further explore the developmental period and reason of abortion for the male sterile plants.

METHODThe morphological characteristics of B. chinense male sterile and normal plants were investigated and compared. The anther development process and pollen viability of two types of plants were examined by microscopic assay.

RESULT AND CONCLUSIONThe shapes and sizes of anther and filament were different between the male sterile and the normal plants. For the male sterile plant's, the filament size was no more than 1/2 of that of normal plants and the anthers were shriveled, failed to dehisce and pollinate naturally, and the pollen grains in the anthers had no vitality. Other morphological characteristics were similar between two types of plants. The main reason leading to male sterility of B. chinense was the abnormal development of tapetum cells with two circumstances. The one is that the tapetum cells degraded early during the period of microsporocyte phase to tetrad phase and the other is that the tapetum cells proliferated with delayed degradation in the tetrad to uninucleate phase.