无核白葡萄的无核果形成的组织形态学研究

A MORPHOLOGICAL STUDY OF SEEDLESS FRUIT FORMATION IN THE GRAPE CULTIVAR 'WUHEIBAI'

To clarify the seedless berry formation mechanism of the grape cul-tivar 'Wuheibai' , pre- and post- flowering morphology of the ovule and the embryo sac were histologically compared between 'Wuheibai' and the seeded cultivar 'Campbell Early'. The results are summarzed as follows. 1.'Wuheibai' was proved to be capable of both autonomic and stimulative parthenocarpy. 2. 'Wuheibai' showed normal pollen fertility. 3. A high percentage of ovules showed abnormalities in the development of inner integument, micropylc and embryo sac in the full bloom stage. 4. 'Wuheibai' was slightly inferior to 'Campbell Early' in pollen tube elongation but pollen tube penetration occurred in 60% of all ovules as obscrred in the former. 5. Abnormal division occurred in the endosperm nucleus at high incidence in the early stages after flowering, and most zygotes remained undivided, and then degenerated. Only a few zygotes showed several divisions, after which they stopped dividing and eventually degenerated to vestiges. These finding suggested that 'Wuheibai' produces seedless berries because it is incapable of forming normal seeds.