银杏雌配子体发育过程中淀粉和蛋白质的积累与代谢

Research on Starch and Protein Accumulation and Metabolism During the Development of the Ginkgo biloba Female Gametophyte

以20年生银杏核用品种‘佛指’(Ginkgo biloba L.‘Fozhi’)为试材,通过树脂切片对雌配子体发育过程中淀粉和蛋白质形成与代谢进行显微和超微结构观察。结果表明:(1)雌配子体发育过程中,细胞内淀粉和蛋白质的积累呈现规律性变化。表现为受精作用发生前,套细胞、帐篷柱细胞和颈细胞内迅速积累大量淀粉粒,靠近颈卵器周围胚乳细胞中的淀粉粒逐渐被转移而减少。受精作用发生时,套细胞和帐篷柱细胞内淀粉粒代谢迅速,靠近颈卵器周围的胚乳细胞中淀粉粒全部消失,细胞壁呈现皱缩解体现象,颈细胞的细胞壁开始解体。受精作用完成后,套细胞、帐篷柱细胞、颈细胞和颈卵器周围胚乳组织出现相继解体现象;(2)雌配子体胚乳细胞内的淀粉和蛋白质积累可分为胚乳薄壁细胞增殖期、淀粉粒和蛋白质形成期、淀粉粒和蛋白质快速积累期和淀粉粒和蛋白质缓慢积累期;(3)淀粉体由造粉质体发育而来,每个造粉质体可含一到多个淀粉体,以芽孢或中间缢断的方式增殖。蛋白质体存在P1和P2两种形式,其中P1存在于内部的胚乳细胞中,P2存在于外围的糊粉层中。受精作用发生前套细胞、帐篷柱细胞内充满了大量的淀粉体和蛋白质体等营养物质,并分布有较多的线粒体、内质网和小泡等细胞器。

Twenty-year old Ginkgo biloba L.＇Fozhi＇was used to investigate nutrient metabolism mechanisms during the development of the female gametophyte,using light microscopy and transmission electron microscopy.The results indicated that during development of the female gametophyte,accumulation of nutrients showed a consistent change.Before fertilization,the jacket cells,tentpole,and neck cells rapidly accumulated large amounts of nutrients,while nutrients in endosperm cells around the archegonia were transferred gradually.During fertilization,nutrient metabolism in jacket cells and tentpole strongly increased.Nutrients in the endosperm cells around the archegonia were drastically reduced,and the endosperm cells and neck cells began to disintegrate.Jacket cells,tentpole,neck cells,and the endosperm tissue around archegonia all disintegrated after fertilization.We also found that the accumulation of nutrients in the endosperm underwent four stages：Parenchyma cell proliferation,the formation of nutrients,a rapid increase in nutrient accumulation,and a slight increase in nutrient accumulation.Finally,we found that starch grains developed from amyloplasts that contain one or more amyloid.These starch grains proliferated by budding or by constriction in the middle.Proteins present included P1 in the inner endosperm cell,and P2 in the outer aleurone layer.Before fertilization,the jacket cells and tentpole were highly active,and filled with high amounts of starch and protein,as well as mitochondria,endoplasmic reticulum and vesicles.