Studies on male gametophyte development of Manilkata zapota (L) Royon

The anther of Manilkata zapota (L) Royan consists of epidermis (one layer), endothecium (one layer), middle layer (four layers). tapetum (one layer) and aporgenous cells. The anther has four chambers and the anther wall developed into dicotyledonous type. The male gametophyte development was observed as follows: with the meiosis of mother cells in microspore, tetrad is formed of which the cytokinesis is simultaneous type and the arrangement is tetrahedral; the micropores completed the mitosis and generated double-cell pollen; the mature pollen is double-nucleus. The epidermis disappeared at the uninuclear microspore stage, the middle layer disappeared at tetrad stage, and the endothecium extended longitudinally and formed colummar fibrous layer at uninuclear microspore stage. The tapetum cells disappeared at uninuelear microspore stage and the tapetum is single nuclear glandular one. The experimental results of artificial germination of pollens showed that the pollen germination rate was very low. The natural germination of pollens were simultaneously obserserved on stigma.