【作者】 王贵民；

【导师】 陈国祥；

【作者基本信息】 南京师范大学 ， 植物学， 2004， 硕士

【摘要】 本实验以全展后的两优培九剑叶为主要研究材料，以全展后的汕优63剑叶为对照，主要研究了在不同衰老期的功能叶片的光合功能特性、抗氧化特性及叶绿体超微结构的变化。结果表明： 1 在剑叶的全展早期，叶绿素含量、可溶性蛋白含量、光合速率、PSⅠ和PSⅡ的活性、叶绿体放氧活性皆呈上升趋势，但叶绿体中ATP的含量下降；膜透性、MDA含量、超氧阴离子含量变化不明显或变化不大、保护酶系统中SOD、POD的活性不断提高、CAT活性稍下降；抗性物质中GSH含量上升，但ASA和脯氨酸的含量下降；叶绿体的体积较小、呈梭形，叶绿体的基粒片层排列紧密。表明在这一时期杂交水稻剑叶的功能不断完善。两优培九和汕优63差异不显著。 2 在水稻剑叶衰老过程中，保护酶系统与抗氧化物质两大系统共同作用，清除体内活性氧自由基，阻止了膜脂过氧化物MDA的大量产生，维护细胞膜系统完整性。其中SOD、POD、谷肮甘肽-抗坏血酸氧化还原系统发挥主要的保护作用，CAT在杂交水稻的衰老过程中，发挥的作用有限。 3 杂交剑叶全展中后期间，与汕优63相比较，两优培九在剑叶的功能持续期，可溶性蛋白含量，PS还原能力，PSⅡ放氧活性，光合速率，光合高值期，叶绿体基粒片层结构排列方式等方面占优势，是其高产的部分原因；两优培九在保护酶活性、抗氧化物质含量上占优势，是抗衰老能力强的主要原因；另外，两优培九的保护酶活性和抗氧化剂含量上占有一定优势，在衰老过程中活性氧自由基的产生和积累较少，细胞和叶绿体的膜结构较完整，又能提高杂交稻的光合作用，籽粒发育获得较多养分，最终在产量上占优势。 4 水稻剑叶全展后期，叶绿体被膜破坏，片层分离，叶绿体的基粒排列疏松，垛叠解体；保护酶系统与抗氧化物质清除氧自由基作用不明显，活性氧自由基大量积累，膜系统受到严重破坏，电子传递与光合磷酸化解偶联，光合作用、呼吸代谢等一系列生理生化反应发生紊乱，叶片完全衰老。更多还原

【Abstract】 Study on Chloroplast Ultrastructure and Photosynthetic Characters of Flag Leaves from High Yield Hybrid Rice During Their SenescenceThe chloroplast ultrastructure, the activities of antioxidases, the photosynthetic characters of the hybide rice flag leaves were studied during senescence. The results showed as follews:During early stage of the full-expanded flag leaves, the photosynthetic rates of flag leaves were high and steady; the electron transport activities of thylakoid membranes were increasing; the activity of antioxidase were also increasing, except CAT,; but the contents of ATP, MDA, O2- , the membrane permeabity all showed a declining trend. The like-shuttle chloroplast was small, with tightly stacking lamellae of grana. These results indicated that photosynthetic funfion was under a gradually maturing period, withouth symptoms of senescence. Meanwhile, there was no difference in these parameters between high yeild hybrid rice "Liangyouopeijiu" and "Shanyou63".During the middle stage of the full-expanded flag leaves, the net photosynthetic rate was decreasing; The Active Photosynthetic Duration (APD) of was about 35 days for "Liangyouopeijiu", 28 days for "Liangyou63", respectively. The protein, GSH, ASA and protrine content of full-expanded flag leaves, ATP content of chloroplast were decreasing, too; The activities of POD, SOD dropped after reached maximum, the activity of CAT went on dropping; The chloroplast expanded, the chloroplast grana was contorting, loosing, some of chloroplast grana decomposited. The antioxidases of "Liangyoupeijiu" were more active than those of"Shanyou63" in this period , the net photosynthetic rate of "Liangyoupeijiu" was higher than that of "Shanyou63".During late stage of the full-expanded flag leaves, the membrane of chloroplast was destroyed, a lot of chloroplast grana decomposited, the connection of chloroplast grana wasn’t tight. The resistences of leaves were getting weaker, the photosynthe-sitic rate was getting lower, almost all the chloroplast showed marked symptoms of in senescence.更多还原