茌梨的胚胎发育和开花结实的相关性研究

茌梨的花药以造孢组织越冬。第二年春,花芽萌动时形成小孢子母细胞。小孢子的发生为同时型。成熟花粉粒为2细胞型。4月初,珠心顶端第三层细胞中的造孢细胞发育为大孢子母细胞,属厚珠心型。胚囊发育属蓼型。胚发育始于4月下旬,受精卵进行横分裂,后经棒状原胚、球形原胚、心形胚和鱼雷形胚,至7月中旬幼胚逐渐成熟。胚的发育属藜型。胚乳发生为核型。茌梨大小孢子的发生和雌雄配子体的形成与花芽、花外形标志之间,有较稳定的相关性。胚和胚乳的发育与果实的生长有一定的相关性。

STUDIES ON THE RELATIVITY BETWEEN CHI PEAR(PYRUS BRETSCHNEIDERI)EMBRYO DEVELOPMENT AND ITS FLOWERING,FRUITING

The anthers of Chi pear overwinter in sporogenous tissue and form microsporocytes at the early or middle March.The microsporogenesis belongs to the simultaneous type.The mature pollen grain is a two-celled structure.The megasporocyte which belongs to the crassinucellate type is formed among the cells of the third layer at the top of nucellus during the end of March or at the early April.The development of embryo sac conforms to Polygonum type.In the Apirl,the fertilized egg starts its cross-division after the dormancy period and undergoes the following stages,such as the clavate proembryo,the global proembryo,the heart-shaped embryo and torpedo-shaped embryo stage.In the middle of July,the young embryo gets ripe gradu- ally.The embryo development of Chi pear belongs to Chenopodiad type while the endosperm development of Chi pear belongs to Nuclear type.In Chi pear,there are stable relations in its microsporogenesis,megasporogenesis,its male,female gametophytes formation and its flower bud,flower morphological character.There is also a certain interrelation of development be- tween the fruit,the embryo and the endosperm.