【作者】 梁文裕；

【导师】 陈伟； 吕柳新；

【作者基本信息】 福建农林大学 ， 植物学， 2003， 硕士

【摘要】 龙眼胚胎的发育状况与果实的品质、坐果率利产量密切相关，因此，研究龙眼胚胎发育时期生物大分子、多胺及特异蛋白等的变化对于阐明龙眼胚胎发育的规律有着重要的理论意义，同时也对龙眼品种的选育、果核大小的调控、食用品质的改善及产量的提高有着重要的生产指导意义。 1 龙眼胚胎发育过程中生物大分子的变化动态 龙眼胚胎的发育状况与胚珠内核酸、蛋白质和淀粉含量的变化密切相关。试验结果表明：每克鲜重胚珠核酸含量在花后10-17d达到最大值，以后逐渐降低，至45d左右达最低值后又平稳回升，是一种两阶段增长模式；以每胚珠鲜重计，DNA含量随胚珠的发育而逐渐增加。RNA的含量变化总体趋势与DNA相似，但DNA含量的变化先于RNA，说明基因转录过程中RNA的变化处于DNA的变化之后。以每克鲜重计，蛋白质的含量变化与核酸的变化类似，以每胚珠鲜重计，蛋白质的积累基本上与RNA的积累平行地进行，说明RNA与蛋白质在翻译水平上是相辅相成的。胚珠内淀粉含量的变化趋势与DNA、RNA、蛋白质略有不同，以每克鲜重计，淀粉的含量变化表现为四段斜率不同的直线式变化，以每胚珠鲜重计则随着胚珠的发育而不断增加，其中52d后增速剧增，表明随着胚胎的发育，储藏物质中淀粉含量大大增加了。 2 龙眼胚胎发育与多胺的变化 研究了龙眼胚胎发育与多胺含量的关系，结果表明：正常发育的胚珠中多胺含量在胚胎发育的各个时期均高于败育胚珠。多胺含量在花后10d为最高，其中Put约占多胺总含量的65％，以后各发育阶段多胺含量逐渐下降，其中31d-38d下降幅度明显。正常胚珠的Spm含量远高于败育胚珠，而Spd除第10d外，也是正常胚珠大于败育胚珠。(Spd+Spm)／(Put)和(Spm)／(PAs)比值变化与龙眼胚珠的发育有直接的关系，两者比值高有利于胚胎发育，反之则不利于胚胎的发育。多胺合成高峰先于核酸和蛋白质，多胺可能通过与核酸的相互作用参与核酸和蛋白质的合成和调节。福建农林大学硕士学位论文 3龙眼胚胎发育时期的特异性蛋白质 应用双向电泳技术分析研究了龙眼胚胎发育时期蛋白质组分的变化。结果表明:大多数蛋白质组分在各发育阶段是相似的，但各发育时期其蛋白质组分也有变化。其中38d存在27.IkD pI7.5，17.5kDpls.2等2个只在该期存在的特异蛋白，45d存在11.4kDpI7.6，13.2kDpxg.9等2个特异蛋白，52d存在22.6kD pI7.2，18.6kD pIS.3，23.5kDpI3.6，18.3 kDpllo.1等4个特异蛋白。3ld胚胎电泳图谱中的蛋白质点数相对较多，表明蛋白质的旺盛合成与积累在3ld胚期，这与测量的蛋白含量的结果基本相似。龙眼胚胎发育过程中特异蛋白的出现或消失，对胚胎的分化发育具有重要作用。更多还原

【Abstract】 The developing condition of longan embryo is closely related to its taste quality, fruit set and production. It is not only of great theoretical importance for explaining regularity of longan embryo development , but also of important practical significance for selecting longan varieties, controlling fruit seeds, improving fruit quality and increasing longan production to study the changes of biomacromolecules, polyamines and specific proteins during longan embyo developing period.1. Changes of biomacromolecules in the process of the longan embryo developmentThe changes of nucleic acid , protein and starch content had an important effect on embryo developing condition in longan. On the basis of fresh weight, the experiment showed that maxium content of nucleic acid in ovules per gram could be reached around 10 to 17 days after anthesis , and decreased gradually until its minimal content could be reached around 45 days after anthesis , after that it began to level off. It was a two periods increasing form . DNA content would be gradually increased with the development of ovules.The changing trend of RNA content resembles that of DNA , but changes of DNA content came after RNA . It indicated that RNA changes followed DNA in the process of gene transcription. Change of protein was paralles with that of nucleic acid per ovule. Accumulation of protein basically paralles that of RNA, it showed that the changes of RNA and protein companied each other on the level of translation. Changing tend of starch content per ovules was slightly different from that of DNA, RNA and protein, the graph for the changes in starch content in ovules showed a broken line of four segments each with a different slop per gram , while the content of starch would increased gradually, especially, its later the process is greatly around 55 days after anthesis . Thus showed that the content in storing substance was greatly increased with the embryo development.2. Relationship between longan’s embryo development and changes of polyaminesThe thesis also studied the relationship between longan embryo development and contents of polyamines . Experiments showed that the contents of polyamines in normal ovules were higher than those in abortive ones during the whole embryogenetic process. The highest levels were reached on 10 days after anthesis. Put among it accounted for about 65% of total contents of polyamines, after this, the contents of polyamines declined gradually. However, the contents of polyamines declined brightly from 31 to 38 days after anthesis . The contents of Spin in normal ovules were very higher than those in abnormal ovules, while Spd was higher in normal ovules than in abnormal vules except for 10 days after anthesis .The studies also showed that low ratios of (Spd+Spm)/Put and Spm/PAs might hindered embryo development. Polyamines contents hit the peak befor the contents of nucleic acid and protein reached maxium, which suggested that polyamines might affect embryo development by regulating the synthesis of biomacromolecules.3. Studies on longan’s specific proteins in the embryo development stagesIEF-SDS-PAGE technique was applied to comparing and analyzing the changes of protein component during longan embryos differentiation and development.The results showed that major components of proteins were generally similar in different developing periods, however, some changes also took place . This experiment discovered 8 new specific proteins in different stages of the embryo development . They were 27.1kD pI7.5,17.5kD pI8.2 on 38 DAA; 11.4kD pI7.6, 13.2kD pI9.9 on 45 DAA; 22.6kD pI7.2, 18.6kD pI8.3, 23.5kD pI3.6,18.3 kD pI 10.1 on 52 DAA. The number of protein points were comparatively higher on 31 DAA gel map , which indicated that rich synthesis and accumulation of proteins appeared in the 31 DAA stage, these findings coincided with the results of the protein contents determination. The appearance or disappearance of the specific proteins might play an important role in longan embryo differentiation更多还原