不同施氮下优质稻植株花后碳氮物质流转与籽粒生长的相关性

以桂华占、八桂香为材料,在高氮(NH,High nitrogen)、中氮(NM,Middle nitrogen)、低氮(NL,Low nitrogen)三个施氮水平下,研究了优质稻花后碳氮物质积累、运转与籽粒生长特征及其相互的关系。结果表明:①在不同施氮水平下,干物质转运效率为53.60%～62.23%,氮素转运效率为12.33%～37.95%,茎鞘和叶片干物质转运对籽粒干物质积累的贡献率为12.33%～37.95%,茎鞘和叶片氮素转运对籽粒氮素积累贡献率为47.93%～117.2%。②施氮水平影响桂华占和八桂香花后碳氮流转及籽粒的生长。高氮条件下增加叶片碳氮同化物的转运,不利于茎鞘碳氮同化物向籽粒转运。增施氮肥在一定程度上提高了地上总氮和籽粒氮的积累量,提高了籽粒氮收获指数,蛋白质含量上升。低氮处理虽能促进茎鞘碳氮同化物的转运率,但籽粒收获指数明显变低。③不同施氮水平下,桂华占和八桂香花后碳氮流转与籽粒的生长间存在密切的相关,花后茎叶干物质运转速度和转运率都与籽粒起始灌浆势呈正相关;籽粒最大灌浆速率与叶干物质运转速度和转运率呈正相关;叶片中总氮转运率与籽粒蛋白质产量呈正相关。花后茎叶氮素积累量的减少,伴随着籽粒氮素积累量的增加和籽粒蛋白质含量的升高是同步的;茎鞘花后同化物碳氮比与籽粒蛋白质含量及产量呈正相关,与籽粒直链淀粉含量及淀粉、蛋白质比呈负相关。不同施氮水平下氮素转运效率和贡献率表现出一定差异,这种差异与水稻植株自身对氮生理利用效率密切相关。

Relationship between Post-anthesis Carbon and Nitrogen Remobilization and Grain Growth of High Quality Indica Rice under Different Nitrogen Levels

Field experiments were conducted in a randomized complete block design with three nitrogen fertilize rate(NH,High nitrogen:210 kgN.ha-1;NM,Middle nitrogen: 150 kg N.ha-1;NL,Low nitrogen: 90 kg N.ha-1) and two indica high quality rice genotypes(Baguixiang and Guihuazhan) to investigate dry matter accumulation and translocation and grain growth after flowering in 2007 and 2009.Results showed that:(i)Dry matter translocation efficiencies ranged from 53.60 % to 62.23 % and nitrogen translocation efficiencies were from 12.33 % to 37.95 %,and dry matter rate contribution of culm and sheath and leaf blade to grain were from 12.33 % to 37.95 %,and nitrogen rate contribution of culm and sheath and leaf blade to grain were 47.93 % to 117.2 % under different nitrogen levels.(ii) Nitrogen application levels made influence on carbon and nitrogen remobilization and grain growth after flowering of high quality indica of Baguixiang and Guihuazhan.Carbon & nitrogen remobilization in culm,sheath,leaf blade were higher under high nitrogen fertilizer application than middle and low N level,while it was not easy to remobilize carbon and nitrogen in culm and sheath to grain,and reduced translocation efficiencies of starch of culm and sheath.Carbon and nitrogen accumulation,weight of panicle,protein content and nitrogen harvest index of grain increased with more nitrogen fertilization.Although low-nitrogen can promote translocation efficiencies of the assimilation of carbon and nitrogen in culm and sheath,but the grain harvest index was significantly lower.(iii) Under different nitrogen levels,grain growth was closely correlated with carbon and nitrogen remobilization.Initial grain filling potential was correlated with dry matter remobilization rate and efficiency of culm and sheath.Maximum grain filling rate was correlated with leaf dry matter remobilization rate and efficiency after flowering.This correlation displayed was positive correlation between the total nitrogen transportation rate of leaf blade and the grain protein yield with more nitrogen application.Grain protein and starch content and accumulation of high-quality rice were more correlated with the translocation rate of total nitrogen in leaves with increasing nitrogen application.The stem and leaf nitrogen accumulation reduced along with the increase in grain nitrogen accumulation and grain protein content increased in synchronization.The C/N ratio of carbon and nitrogen assimilation of culm and sheath after anthesis was positively correlated with protein content and yield and negative correlated with amylose content and ratio of starch and protein.It can be concluded that differences among each N level in nitrogen translocation efficiencies and nitrogen rate contribution depended on the nitrogen utilization and partition agronomic characteristics.