不同氮效率粳稻生育后期产量形成的生理基础

摘要

The objective of this study was to identify the difference of photosynthesis in Japonica rice of Jiangsu under different nitrogen applications;7 rice genotypes including three middle Japonica rice( Wuyujing 3,Nanjing 45,02102) and five late Japonica rice(Wuyunjing 7,Nanjing 44,Nanjing 46,Nanjing 5055) in the pot experiments were chosen to measure their photosynthesis characteristics ,NR,GS,GOGAT,GDH and antioxidant enzyme activi-ties of flag leaves at the flowering stage under different nitrogen applications (150 .0 kg/ha:LN、300 .0 kg/ha:MN, 450 .0 kg/ha:HN ) and their yield component were investigated after harvest .The results showed that the grain weight per plant of Nanjing 45 were 118 .47%,129 .11%,132 .58%,respectively of those in the control Wuyujing 3 under LN,MN and HN,while those of Nanjing 44 were 1.79%,25.10%and 29.79%,respectively higher than the control Wuyunjing 7 in corresponding treatments .With the amount of nitrogen increases ,rice plants increase the a-bility to use high light intensity and alleviate the decrease of the maximum net photosynthetic rate ( Pnmax ) of flag leaves at the 21 d after flowering;Under high concentrations of CO 2 ,the rice varieties increased P nmax by improving their apparent carboxylation efficiency ( ACE) under MN condition .From the perspective of antioxidant capacity ,the increase of superoxide dismutase ( SOD ) was one of the important antioxidant enzymes .Analysis results show that the photosynthetic capacity at 7 d after flowering was more related to the weight of grains .On the other hand , the photosynthetic ability and the antioxidant capacity of at 35 d after flowering were more related to their seed-setting rate.The super rice varieties such as Nanjing 44 and Nanjing 45 are more suitable for the cultivation in medium ni-trogen conditions by inducing the NR and the antioxidant capacity of different time after flowering ,which they resul-ted in the high photosynthetic capability to obtain the high yield .Selection the rice varieties with high ability of pho-tosynthesis would be an important strategy both for high yield and to decrease the N application in future .It would be helpful to increase the yield and reduce the N application by breeding the rice variety with high photosynthetic a -bility in future .%为明确不同施氮量下高产粳稻在产量形成的关键时期光合生理特性的差异，在盆栽条件下，选取3个中粳（武育粳3号、南粳45、02102）和4个晚粳（武运粳7号、南粳44、南粳46、南粳5055），在开花后不同天数，研究了不同施氮量下（150．0 kg/hm2：LN、300．0 kg/hm2：MN、450．0 kg/hm2：HN ）剑叶光合作用对光强和二氧化碳（CO2）响应曲线，氮代谢关键酶如硝酸还原酶（NR）、谷氨酰胺合成酶（GS）、谷氨酸合酶（GOGAT）谷氨酸脱氢酶（GDH），抗氧化酶和非酶系统的抗氧化能力以及耐光氧化表现等，并在收获期考察其产量构成因子。结果表明：超级稻中粳南粳45和晚粳南粳44在LN、MN和HN的单株产量分别比对照武育粳3号和武运粳7号有所提高；随着施氮量的增加，水稻对高光强的利用能力增强，并可缓解开花后35 d剑叶的最大净光合速率（ Maximum net photosynthetic rate ，Pnmax ）的下降；而供试材料在LN或者MN下，在高CO2浓度下可通过提高表观羧化效率（ Apparent carboxylation efficiency ，ACE），达到与HN的Pnmax ，提高CO2浓度有利于减氮；开花前期氮代谢相关酶活性诱导增加，后期超氧化物歧化酶（ Superoxide dismutase，SOD）的活性诱导增加以缓解后期光氧化，其中超级稻南粳44和南粳45在不同的氮素处理下，均具有中等耐光氧化和耐荫的特性。相关性分析表明，花后7 d的叶片的光合能力与千粒质量有关，而花后35 d，功能叶片的抗氧化能力则影响其结实率。可见，超级粳稻南粳44和南粳45在中等氮素下，可通过开花前期诱导NR和开花后期抗氧化能力增强，最大限度地发挥其叶片的光合功能，从而表现稳产高产。今后兼顾选择具有高光合特性的水稻品种，将是实现水稻高产和减氮统一的有效途径。