Abstract:Microsporogenesis development of male sterile of Lavandula pinnata grown in South China was observed by light and electron microscopy. The results showed that the male flowers of L. pinnata had four stamens, each bears four microsporangia. Development of anther wall belonged to Dicotyledonous Type, and the anther wall was composed of an epidermis, endothecium, middle layer(s) and glandular tapetum. The cytokinesis following meiosis was simultaneous, producing tetrahedral and decussational tetrads. The development of the microspore could be divided into sporogenous stage, meiosis stage, and the early and late stage of the microspore. Binucleate pollen stage and mature pollen stage were not observed. Sterile pollens occured in the mononuclear pollen stage, the cytoplasm degenerated and disappeared developing abnormal pollen grains. Microsporogenesis were normal before the mononuclear pollen stage. The sterile characteristics showed tapetal cells degenerated too early and mictochondria was abnormal during the tetrad stage, there were abnormal spaces between callus wall and mother microspores wall, and the granules appeared in the anther wall cells unconventionally.
