人心果雄配子体发育的研究

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

人心果花药由表皮(1层)、药室内壁(1层)、中层(4层)、绒毡层(1层)和造孢子细胞组成,药壁发育双子叶型,花药四室。雄配子体发育经由小孢子母细胞减数分裂形成四分体,该四分体胞质分裂为同时型,四分体排列为四面体型,小孢子再经有丝分裂形成2-细胞花粉,成熟花粉为2-核花粉。花药壁层的变化是表皮在单核小孢子产生期消失,中层在四分体时消失,药室内壁在单核小孢子期径向延长成柱状纤维层;绒毡层在四分体期开始解体,为单核腺质绒毡层。花粉活力测定表明95.02％有活力;人工萌发实验表明花粉萌发率很低;同时观察花粉在柱头上自然萌发。

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.