模拟水分胁迫条件下水稻的氮素营养特征

在正常及PEG模拟水分胁迫条件下研究水稻对不同质量比例(100／0，75／25，50／50，25／75和0／100)铵态氮/硝态氮处理的响应特征。结果表明，两种培养条件下，水稻均在NH4^ -N和NO3^--N混合营养时生长更好，氮素养分吸收更多；正常培养的水稻幼苗在NH4% -N／NO3^--N为75／25时生长最好，而模拟水分胁迫培养则以25／75处理生长最好；模拟水分胁迫处理显著促进水稻对NO3^--N的吸收并抑制NH4^ -N的吸收；正常培养条件下，NH4^ -N／NO3^-N为75／25时水稻幼苗可获得最高的水分生产效率，而模拟水分胁迫培养的幼苗水分生产效率随NO3^-N施用比例增加而提高。

Nitrogen nutrition characteristics of rice in simulating water stress condition

A solution cultivation experiment,with/without PEG,was conducted under different ration of NH 4 -N and NO 3--N(100/0,75/25,50/50,25/75 and 0/100)to evaluate the effects of mixed nitrogen nutrition on growth and water use efficiency of rice cultivated in simulating water stress condition.The results obtained were as follows.The rice crop could grow better and take up more nitrogen under a mixed provision of ammonium and nitrate than under single provision of either ammonium or nitrate both in normal and simulating water stress solution cultures.The best growth of rice seedling was found in the NH 4 -N/ NO 3--N ratio of 75/25 in normal solution culture while it was in the NH 4 -N/ NO 3--N ratio of 25/75 in simulating water stress solution culture.It seems that simulating water stress increased the uptake of nitrate and decreased that of ammonium by the rice.The highest water use efficiency(WUE)by the rice could be obtained in the NH 4 -N/ NO 3--N ratio of 75/25 in normal solution culture whereas WUE was increased with the increase of percentage of nitrate in total N supply in simulating water stress solution culture.