黄金梨胚珠、花粉发育及花粉败育过程的显微观察

观察了黄金梨的胚珠、胚囊、花粉发生发育过程中细胞形态变化特征。结果表明:黄金梨的胚珠、胚囊、花粉发育是在春季萌芽到开花过程中完成的。在开花前28d花芽萌动初期,胚珠原基出现,花药囊内为小孢子母细胞;花前21d胚珠原基分化出内外珠被,四分体开始出现;花前14d四分体出现率最高;开花时胚囊形成,花粉败育并形成空花药囊。造成黄金梨花粉败育的原因是小孢子母细胞减数分裂后形成的四分体及四分体分离后形成的早期花粉细胞无细胞核,早期花粉细胞液化不能形成较厚硬的外壁而解体。

Microscopic observation of the developmental process of ovule and pollen sterility of Whangkeumbae pear cultivar

The developmental process of ovule, embryo sac and pollen, the pollen sterility and the changes of their cytological morphology of Whangkeumbae pear cultivar (Pyrus pyrifolia Nakai) were observed and studied. Results showed that: the development of ovule, embryo and pollen were completed in the period from bud burst to the full blossom stage in spring. The primordium of ovule and mother cell of microspore both appeared 28 days before full blossom; and 21 days before full blossom the inner and outer integument of the primordium differentiated, meanwhile tetrad appeared. Most of the tetrad appeared 14 days before full blossom. At full blossom stage the embryo sac shaped up, pollen aborted and anther became empty. The cause that led pollen to be sterile of Whangkeumbae pear cultivar was that there was no nucleus in the cell of tetrad and the early pollen dissociated from the tetrad, and degenerated due to vacuolization of pollen cell and lack of thick exine.