【作者】 陈娟；

【导师】 王忠；

【作者基本信息】 扬州大学 ， 植物学， 2003， 硕士

【摘要】 本文测定了粒重差异较大的四个水稻品种在灌浆过程中颖果鲜干重、脱氢酶活性、呼吸速率、ATP含量、抗氧化酶(CAT、SOD和POD)活性和可溶性蛋白质含量等随花后天数的变化，并重点研究了果皮的结构和生理功能，得到如下主要结果： (1)颖果鲜干重在花后呈“S”形曲线增加，颖果鲜干重的增加速率与颖果的含水率及生理活性有关系，颖果的含水率和生理活性高，则鲜干重增加快；维持生理活性的时间长，则鲜干重增加的时间长。 (2)在发育完善的子房壁的中层细胞的细胞质中分布着许多淀粉体和叶绿体；叶绿体中含有叶绿素，并且含有光合碳同化的关键酶——Rubisco；在果皮呈现绿色时具有光合放氧的功能；子房壁在发育初期积累了用于果皮细胞生长的淀粉。 (3)大粒品种与小粒品种相比，在颖果发育过程中含水率降低的速率小，维持灌浆的时间长；颖果中脱氢酶的活性、呼吸活性和ATP含量高，维持活性的时间长；颖果中与细胞衰老有关的酶SOD、CAT活性高，POD活性低，维持酶活性的时间长；颖果合成蛋白质的时间长；大粒粳稻与小粒籼稻相比，大粒粳稻颖果在发育初期子房壁中大量积累用于细胞生长的淀粉，且子房壁细胞生长期长，达到花后15 d时，果皮显著增大，而小粒籼稻子房壁中淀粉积累量少，细胞生长量小，果皮细胞在花后第10 d就开始收缩；大粒粳稻果皮中叶绿素含量，果皮光合活性、Rubisco含量等也高于小粒籼稻；推测大粒品种之所以大的原因在于一方面其库活性高，抗衰老能力强，从而维持了较强的灌浆势和较长时间的灌浆活性；另一方面其库容大，接纳同化物的空间大。 (4)在供试的四个品种中，粳稻与籼稻相比，粳稻颖果前期灌浆较慢，但后期灌浆速率超过籼稻，且能维持较长的灌浆时间；脱氢酶活性、呼吸活性和ATP含量前期比籼稻低，但后期高；SOD、CAT活性较高，POD活性较低；果皮中叶绿素含量，果皮光合活性、Rubisco含量等也较高；推测粳稻之所以灌浆时间长，与其抗衰老能力强，从而维持颖果中果皮和胚乳细胞的活力，保证灌浆物质的接纳有一定的关系。更多还原

【Abstract】 Four rice varietics, whose grain weight were remarkably differnt, were taken as plant material in this experiment. And the changes of fresh/dry weight, dehydrogenase activities, respiratory rate, ATP content, activities of CAT, SOD,POD, content of soluble protein and so forth within days after flowering of their caryopsis, the changes of ultrastructure, chlorophyll content, pholosynthetic oxygen-evolving activities, and Rubisco content of the pericarp of big grain japonica and small grain indica were highlighted, and the main results were as follows:(1) fresh and dry weight of caryopsis shows a increase in the form of "S", and its increase rale was coherent with its water content and its physiological activities, high water content and high physiological activity will lead to high increase in fresh anil dry weight; and a long time to maintain its physiological activities, and Ihe fresh and dry weightwill increase in a longer time.(2) many starch grain and chloroplast in the middle layer cell of the well developed ovary wall; chloroplast is composed of chlorophyll and the key enzyme of photosynthesis Rubisco. The pericarp has the ability of photosynthesis andoxygen evolving, and many starch used for the growth of pericarp cell was accumulated in ovary wall at early stage of development.(3) comparison between the varieties of big grain and small grain, Big grain caryopsis has stronger milking potential, slower water loss, and a longer period of maintaining milking; while small grain caryopsis has weak milking potential, fast water loss, and a shorter period of maintaining milking; Activities of dehydrogenese, respiralory activities of big grain caryopsis were greater than those of small grain caryopsis, and it has longer period of maintaining activities than the small graincaryopsis; Activities of SOD and CAT, which has sonic relationship with cell senescence, were higher than those of small grain varieties, but POD activities were smaller than thai of small grain varieties, and it has a longer period of maintaining the activities ol enzymes the lime for the big grain caryopsis to synthesize protein was longer than small grain varieties; Compared with big grain japoniea and small grain indica, large amount of starch were accumulated at ovary wall during early period of development, the ovary wall cell has a longer growth period, pericarp enlarge significantly 15 days after flowering, and small amount of starch accumulate in ovary wall of small grain indica, the cell has a small growth amount, the pericarp cell begin to contract after flowering; the chlorophyll content, the photosynthetic acitivities and content of chylorophyll of big grain japonica pericarp were all smaller than small grain indica; thus it can be concluded that reason for the big sizc of the big grain lies in that the sink has a higher activities and stronger ability of anti-senescence , thus a stronger milking potential and a longer period of milking activities were maintained; on the other hand, il has a bigger volume to accept assimilate,(4). compared between joponica and indiea, japonica has slower milking rate at early stage, but has a bigger milking rate than indica at late stage, and can maintain a longer milking period; japonica has a lower respiratory rate and ATP content at early stage, but has higher physiological activities at late stage than those of indica; Activities ol SOD and CAT during all the period of japonica were higher than those of indica; chlorophyll content, photosynthetic activities and Rubisco content of japonica pericarp were higher than those of indica; it could be concluded that the reason for the longer period of milking were because that it has a stronger ability of anti-senescence , thus the activity of caryopsis pericarp and endosperm cell were maintain, and the acceptance of milking material were ensured.更多还原