【作者】 于维华；

【导师】 陈鹏；

【作者基本信息】 扬州大学 ， 植物学， 2004， 硕士

【摘要】 连续两年选择银杏(Ginkgo biloba L.)的三个核用主栽品种佛指、洞庭皇和龙眼为试验材料，从盛花后15 d开始定期取样，分别测定分析种实的发育进程及其相关的解剖结构、超微结构和成分变化，并对中种皮的PCD进行了分析研究，结果表明： (1)银杏发育过程中，种实纵、横径和单粒重在盛花后60 d内，生长速率较快，盛花后80 d至种实成熟生长趋于平缓。纵、横径的主要生长天数为56～58 d，单粒重的主要生长天数多于纵、横径4～9 d。三个品种的纵、横径主要生长天数基本相同，但龙眼发育进程最快，进入旺盛生长期较早，同时进入盛末期也最早，且单粒重主要生长天数比佛指和洞庭皇少3～5 d。 (2)种实含水量在盛花后不断增加，45～60 d达最大值，后开始下降；可溶性糖含量在盛花后45 d左右出现第一个高峰，后出现下降，盛花后80 d至种实成熟又显著升高；淀粉含量在盛花后一直上升，其中洞庭皇和龙眼的淀粉含量在盛花后100 d有所降低；蛋白质含量在种实发育过程中始终呈下降趋势，盛花后15 d含量最高，达到20.16％，第30～60 d缓慢降低，第60～80 d急剧下降，此后至种实成熟趋于稳定；钙含量在种实发育过程中逐渐下降，与蛋白质的变化规律相似，三个品种中平均钙含量从大到小依次为佛指、龙眼和洞庭皇。 (3)银杏种实盛花后30 d出现第一个呼吸高峰，第30～60 d呼吸强度急剧下降，此后至成熟，呼吸强度变化相对稳定。在种实发育过程中，外种皮、中种皮和内种皮细胞排列及形状的差异逐渐明显。随着细胞增大，单位面积内细胞数目减少，其中佛指尤为最明显。种实发育的Ⅰ-Ⅳ期细胞形状由椭圆形变为近圆形，到Ⅳ期长宽比值显著增大，细胞变为长卵圆形。其中内种皮的长宽比值变化高于同时期的外种皮和中种皮。三个品种中，龙眼种实中种皮分化最早，Ⅱ期结构就已明显，Ⅳ期其已木质化。 (4)银杏中种皮形成过程中，细胞发育进程不一，细胞核形状多样，在Ⅳ期前5 d细胞核开始趋向细胞壁，核内有核仁，各种细胞器结构完整。随着中种皮细胞的生长，Ⅳ期佛指和洞庭皇的中种皮细胞壁染色为深蓝色，核仁消失，细胞核浓缩，扬州人学硕士学位论文细胞器开始解体。W期后sd核膜消失，核崩解成碎片趋向细胞壁，细胞器进一步解体。经提取种实的DNA作琼脂糖凝胶电泳，三个品种在W期都出现了明显的条带，而前三个时期则不明显，说明银杏中种皮的形成过程是细胞程序性死亡(尸CD)。(5)银杳中种皮由若干层管胞组成，管胞上有不同程度的穿孔破裂，其破裂的形状、大小和数量依品种而异，并随着种实的日趋成熟，管胞穿孔的数目和面积增加。品种间管胞直径经测定为龙眼>佛指>洞庭字.。更多还原

【Abstract】 Fozhi, Dongtinghuang and Longyan, three important seed-purpose cultivars of Ginkgo biloba L., were selected to sample on schedule 15 d after full blossom for measuring and analyzing the seed development and the related changes of anatomical, ultra-structure and components in following two years, and PCD of mesosperm were also studied. The results were as follows:(1) During development of Ginkgo biloba ,the length ,diameter and weight of seed, increased faster within 60 d after full blossom, which growth rate tended to slow from 80 d after full blossom to ripeness. The main growth days of length and diameter were 56~58 d, and those of single seed weight were 4~9 d more than length and diameter. The main growth days of length and diameter were similar among the three cultivars, but Longyan developed fast, which entered blooming earliest and stop growth earliest, too.Its main growth days of weight were 3~5 d less than those of Fozhi and Dongtinghuang cultivars.(2) The relative components in seed varied during development, water content increased and reached to the maximum on 45~60th d after full blossom, then decreased after that; content of soluble sugar had a top on 45 d after full blossom and raised obviously from 80 d after full blossom to ripeness; starch content increased after full blossom and had a decrease for Dongtinghuang and Longyan on the 100th d; protein content decreased during seed development and reached to the highest level , 20.16%,on 15 d after full blossom, then fell slow on 30-60 d and decreased sharply on 60~100 d, the growth showed stable till harvest; change rules of both calcium and protein were resemble , which inclined to decline during development. The average calcium content from highest to slowest was Fozhi, Longyan , Dongtinghuang in order.(3) The respiratory intensity (RI) of seed had a maximum on 30 d after full blossom, RI fell rapidly from 30 to 60 d and changed little after then till maturity. Difference of cell arrangement and shape of episperm, mesosperm and endopleura became obvious during seed development. Cell size increased, number in unit area decreased. The reduce of Fozhi was in evidence. Cell shape changed from ellipse to round, the ratio of length to width increased obviously and cell changed to long ellipse. Ratio of length to width of endopleura was higher than that of episperm and mesosperm. Among the three cultivars, Longyan differentiated earliest, which structure was apparent at phase II and mesosperm lignified at phase IV.(4) The cells development of seed varied during mesosperm formation in Ginkgo biloba. Karyon shape diversified and began to move to the cell wall 5 d before phase IV,at that time nucleolus existed in the cell and organelle kept intact. Mesosperm cells wall of Fozhi and Dongtinghuang was dyed to blackblue at phase IV. Nucleolus disappeared and karyon condensed,organelle began disaggregation.On 5 d after phase IV,karyotheca disappeared, karyon broke down and the fragment moved to the cell wall. Organelle disaggregated further. DNA ladder was found on phase IV by agar gel electrophoresis after seed DNA was extracted, while the ladder couldn’t be seen in phase I to phase III. All these showed the formation of mesosperm of Ginkgo biloba was programmed cell death(PCD).(5) The mesosperm of seed was made up of layers of tracheids , which had different kinds of holes on it, and the changes of shape, size and number of holes were dependent on the cultivars. With the ripening of seed, the number and area of break of tracheids was increasing. The diameter of tracheids was Longyan) Fozhi >Dongtinghuang in order.更多还原