Abstract: The fluorescence parameters of the 1st, 2nd, 3rd and 4th leaves from the top of culms in two rice varieties (Huajing 2 and Wuxiangjing 9) were measured with FMS-2 at different growth stages under three nitrogen levels, and the leaf nitrogen contents were correspondingly determined by destructive sampling and chemical assay. The leaf nitrogen contents and fluorescence parameters changed significantly with nitrogen levels, tending to increase with the nitrogen application rates. The fluorescence parameters exhibited a parabolic shape over the growth progress, initially increased until heading and then decreased to the lowest from heading to maturity stages. The distributions of fluorescence parameters on main culm in all treatments were L1>L2>L3>L4 (L1, L2, L3 and L4 mean the 1st, 2nd, 3rd and 4th leaf from the top). For the same variety, leaf nitrogen contents at different leaf positions were significantly correlated to fluorescence parameters, with better performance in Huajing 2 than in Wuxiangjing 9. With combined rice varieties, leaf nitrogen contents at different leaf positions were linearly related to fluorescence parameters ΦPSⅡ and qP. Different regression equations should be used to estimate leaf nitrogen contents at different leaf positions with ΦPSⅡ and qP. The results indicated that fluorescence parameters ΦPSⅡ and qP could be potentially useful for estimating leaf nitrogen content in rice.

Key words: rice, leaf position, leaf nitrogen content, fluorescence parameter, relationship

摘要： 在3个供氮水平和2个水稻品种(华粳2号和武香粳9号）的田间试验条件下，测试分析了不同处理水稻顶部4张完全展开叶片氮含量及对应的荧光参数。不同供氮水平的水稻叶片氮含量和荧光参数差异明显，均随施氮量的增加呈上升趋势。叶片荧光参数随生育期推迟呈抛物线型变化，以抽穗期为界先上升后下降，直到成熟期降为最低。叶片荧光参数随不同叶位的变化规律为：顶1叶>顶2叶>顶3叶>顶4叶。同一水稻品种各叶位叶片氮含量分别与荧光参数呈极显著相关，且华粳2号的相关性高于武香粳9号。综合水稻品种的不同叶位，叶片氮含量与荧光参数ΦPSⅡ、qP均呈良好的线性相关。基于ΦPSⅡ和qP宜采用不同的回归方程来反演不同叶位叶片氮含量。因此，荧光参数ΦPSⅡ和qP有可能用来估算水稻叶片氮含量。

关键词: 水稻, 叶位, 叶片氮含量, 荧光参数, 相关关系