【作者】 金鑫鑫；

【导师】 陈鹏；

【作者基本信息】 扬州大学 ， 果树学， 2010， 硕士

【摘要】 银杏（Ginkgo biloba L.）是世界珍贵的孑遗植物,具重要的研究与开发利用价值。银杏种实药膳兼用已发展成为我国重要的支柱产业。本研究选择银杏核用主栽品种‘佛指’为试材,对传粉期胚珠设置三种不同的处理:花粉授粉处理、套袋不授粉处理、GA₃处理。用整体解剖法观察了银杏胚乳游离核分裂、分布及数目的统计,用半薄切片、石蜡切片等技术和方法系统观察和分析了银杏胚珠发育和胚乳细胞形成的机制,一方面对于研究银杏在裸子植物系统分类中的地位具有极为重要的意义,另一方面对于研究银杏种实的调控提供理论依据和技术支撑。主要研究结果如下:1、授粉后21 d银杏胚珠发育正常,胚珠横径增长5.7282 mm,胚珠纵径增长6.5972 mm;未授粉处理后21 d银杏胚珠停止生长并脱落,胚珠横径仅增长0.1014 mm,胚珠纵径仅增长0.4011 mm;GA₃处理后21 d银杏胚珠停止生长并脱落,胚珠横径仅增长0.1025 mm,胚珠纵径仅增长0.3111 mm。2、授粉后20 d珠被最大厚度达958.8622μm,珠心顶端组织和海绵组织缓慢退化;未授粉和GA₃处理后20 d珠被组织开始解体,珠被最大厚度分别为375.3811μm、381.2312μm,珠心顶端组织和海绵组退化干瘪,且退化速度为:海绵组织>珠心顶端组织>珠被。3、授粉后5 d珠被外侧正在形成分泌腔;授粉后15 d珠被外侧细胞不断增大,珠被内侧薄壁细胞层数不断增加;授粉后20 d分泌腔分化成熟。未授粉处理和GA₃处理后15 d,珠被内外侧的细胞出现皱缩,至授粉后20 d,珠被内外侧开始解体,且珠被内侧解体早于珠被外侧。4、授粉后5 d,珠心顶端组织由大量排列紧密的薄壁细胞组成,细胞核小且位于细胞一端;授粉后10-15 d,薄壁细胞沿胚珠的纵轴方向伸长,细胞核变大且位于细胞的中央;授粉后20 d,珠心顶端细胞分化减慢,薄壁细胞细胞核变小。未授粉和GA₃处理后10 d,珠心组织开始退化,细胞壁皱缩呈不规则状,细胞核出现解体;处理后15-20 d,珠心组织干瘪,珠被内部形成大空腔。5、授粉后3-5 d海绵组织由5-6层细胞紧密排列而成,内层细胞染色较浅,外层细胞中细胞质浓,染色深;授粉后10 d,海绵组织的排列开始疏松,细胞呈近方形;授粉后15-20 d海绵组织开始退化;授粉后25 d海绵组织细胞退化为1-2层。未授粉和GA₃处理后3-6 d,海绵组织由5-6层细胞紧密排列而成;处理后10 d,海绵组织开始疏松;处理后15-17 d,海绵组织退化为1-2层;处理后20 d,海绵组织退化为一层死细胞。6、银杏胚乳发育的核期时间较长,约为授粉后5-30 d,游离核以有丝分裂为主,也伴随着无丝分裂的进行。以授粉后5-20 d游离核数目增加最快,以后游离核数目增加缓慢。同时,随着游离核的不断分裂,游离核膜状球体逐渐由椭圆形渐变为圆球形。授粉后5-7 d游离核呈球形,数目较少且多分布于细胞质中央;授粉后9-13 d游离核数目不断增加,同时游离核在膜上分布趋于均匀;授粉后15-20 d游离核数目增加且向四周移动。未授粉处理和GA₃处理的雌配子体游离核在处理后3-6 d游离核数目较少且多分布于细胞质中央;处理后10 d游离核数目不断增多;处理后15-17 d游离核停止分裂且原有分裂的游离核退化消失,仅剩下退化的海绵组织围成的空心。7、游离核持续分裂到约4000-5000个时即进入细胞化期,银杏胚乳细胞化的时间约为授粉后30-65 d。授粉后30 d,首先在核周围形成一层开放细胞,靠近中央大液泡一侧无细胞壁,周边的细胞向心游离生长;授粉后45 d,胚乳细胞层数由1层逐渐增加到2-3层,大部分的细胞处于空洞,很少观察到淀粉体的分布;授粉后55 d胚乳细胞层数快速增殖至6-7层;至授粉后60 d所占空腔被胚乳细胞完全填满,胚乳细胞停止分裂,细胞化完成。本研究结果对于指导银杏种实的优质生产提供理论依据和技术支撑。更多还原

【Abstract】 Ginkgo biloba L., a lonely surviving precious plant in the world, has an important value of research and development. It’s seed stone has been used as a medicated alimentation and has been developed into an important industry in our country.‘G. Fozhi’, an important seed-purpose cultivar of Ginkgo, was used as a material to take the below treatments: pollination on ovules, unpollination and GA₃ treatment. The divisive method, distribution and the statistic of number of free nucleus of Ginkgo were accomplished by the method of total dissection. The mechanisms of ovule development and the formation of endosperm cells were systematically observed and analyzed by the techniques and methods of semi-thin section and paraffin section. On the one hand, it has great importance for the study of the position of Ginkgo biloba in the taxonomy of gymnosperms, on the other hand, it provides theory and technical support for the study of the regulation of ginkgo seed. The main results are briefly summarized as follows:1. Ovules of Ginkgo developed normally within 21 days after pollination. The diameter of ovule increased by 5.7282 mm, and its length increased by 6.5972 mm; But the unpollinated ones stopped growing and fell off by then, its diameter only increased by 0.1014 mm, the length of it increased by 0.1021 mm; The ovules which were treated by stopped growing and fell off by then either, the diameter of ovule increased by 0.1025 mm, its length increased by 0.3111 mm.2. After 25 days by pollination, the maximum thickness of the integuments of ovules reached 958.8622μm, the peak of nucellar tissue and spongy tissue degraded slowly. The integuments of ovules which were not pollinated or GA₃ treated began to disintegrate at 25 days after pollination, their respective maximum thickness is 375.3811μm and 381.2312μm. The peak of nucellar tissue and spongy tissue degraded and shriveled. The rates of degradation are: spongy tissue> peak of nucellar tissue > integument.3. After 5 days by pollination, the outer integument began to form secretory cavity; 15 days after pollination, the outer cells of the integument increased constantly, and the parenchyma cells inside the beads were growing; 20 days after the pollination, the secretory cavity was completely differentiated. 15 days after unpollination and GA₃ treatment, cells of the outer integument and inner integument began to shrink; And 20 days after the treatments, cells of the outer and inner integument began to dissolve, and the inner ones dissoved earlier than the outer ones.4. After 5 days by pollination, the peak of the nucellar tissue were made up of a large number of close parenchyma cells, the nucleus of the cell was small and it was located in one end; 10-15 days after pollination, the parenchyma cells elongated along the longitudinal axis of the nucleus, the nucleus of the cell became large and it was located in the center of the cell; 20 days after the pollination, the differentiation of the cells of the peak in nucellar tissue slowed down, the volume of the parenchyma cells no longer increased and the nucleus became smaller and smaller. After 10 days by unpollination and GA₃ treatment, the nucellar tissue began to degenerate, the cell wall shrinked and became irregular-shaped. The nucleus of the cell occurs disintegration. 10-15 days after the treatments, the remaining part of the nucellus shriveled and the inner integument formed large internal cavity.5. After 3-5 days by pollination, the spongy tissue was arranged in close by 5-6 layers, the inner cells stained shallowly, the cytoplasm of the outer cells was dense and stained deeply; 10 days after pollination, the array of the spongy tissue cells became loose and the shape was nearly square; 5 days later, the inner spongy tissue began to degenerate; 25 days after pollination, the spongy tissue degenerated to 1-2 layers. 3-6 days after unpollination and GA₃ treatment, the spongy tissue was arranged in close by 5-6 layers; 10 days after the treatments, the spongy tissue became loose; 15-17 days after the treatments, the spongy tissue degenerated to 1-2 layers; The spongy tissue degenerated to one layer of dead cell 20days after the treatments.6. The development of female gametophyte experienced free nucleus stages from 5 to 30 days after pollination. Free nucleus splitted mainly in mitosis, but also associated with the amitosis after pollination. The number of the free nucleus grew the fastest 5-20 days after pollination, later, the number of the free nucleus increased slowly. Meanwhile, with the constant division of free nucleus, membranous oval gradually changed from ball to spherical. 5-7 days after pollination, free nucleus became less; 9-13 days after pollination, the number of the free nucleus increased constantly, at the same time, the free nucleus distributed uniform on the membrane; 20 days after pollination, free nucleus were pushed around. 3-6 days after unpollination and GA₃ treatment, free nucleus were less and mostly distributed in the central of cytoplasm; 10 days after the treatments, the number of the free nucleus increased constantly; 5-7 days later, free nucleus stopped dividing and original divided free nucleus disintegrated and disappeared.7. When it had formed about 4,000-5,000 nucleus, it was cellularization period. This period was about 30-65 days after pollination. 30 days after pollination, one layer of opening cells was formed which had no cell wall at the side near central cavum in the periphery. 45 days after pollination, the endosperm cell layers gradually increased from 1 layer to 2-3 layers, most of the cells were in a hollow, the distribution of amyloid was rarely observed; After 55 days by pollination, endosperm cell layers increased to 6-7 layers quickly; Cells around grew centripetal and dissociative, till cavum was filled with endosperm cells and the cellularization was finished after 60 days by pollination.The results of the study provides theoretical basis and technical support for the guiding of the high-seed-quality production of Ginkgo biloba.更多还原