Abstract:

In order to explicit the optimal N fertilizer application in ‘Xindao No.18’ and the relationship between rice yield and leaves characteristics, a field experiment with 0, 232.5 kg/hm2, 255.0 kg/hm2, 277.5 kg/hm2, 300 kg/hm2, 322.5 kg/hm2 and 345 kg/hm2 N fertilizer application was carried out in 2011 at the farm of Xinxiang Academy of Agricultural Sciences Henan Province. The difference and the relationship between rice yield and characteristics of the top 3 leaves were investigated using ‘Xindao No.18’ under different N levels. The results showed that rice yield rose firstly and then fell down as N fertilizer application increasing. When the yield reached maximal value at 255 kg/hm2 N level, the comprehensive expression of the top 3 leaves was better than those of other N levels. The infection of N fertilizer on the length of top 2nd leaf was much bigger than that of the top 1st leaf, while the width of top 1st leaf than that of top 3rd leaf. This showed that the effects of N fertilizer on the leaf traits mainly showed on the length of top 2nd leaf and the width of top 1st leaf. The multi-dimensional gradually regression analysis indicated that the established regression equation took yield as the dependent variable, and the leaf conformation traits as the independent variables respectively by using the length of top 2nd leaf, the width of top 1st leaf and LAI reached the  highly significant level (r=0.996 2**). A conclusion indicated that the length of top 2nd leaf, the width of top 1st leaf and LAI contributed more to yield.

Key words: rice, nitrogen (N), yield, top three leaves, leaf area index (LAI)

摘要：

以新稻18号为试验材料，在大田条件下研究了0、232.5 kg/hm2、255.0 kg/hm2、277.5 kg/hm2、300.0 kg/hm2、322.5 kg/hm2和345.0 kg/hm2纯氮水平下水稻产量、叶片形态特征的差异及其之间的关系。结果表明，随着施氮量的增加，水稻产量呈先增加后降低的趋势，至255 kg/hm2纯氮水平下水稻产量达最大，此氮肥水平下水稻上三叶的受光姿态较其他处理综合表现较好。从不同氮肥处理对水稻上三叶的形态特征影响来看，倒二叶长受氮肥影响较大，倒一叶长受氮肥影响较小；倒一叶叶宽受氮肥影响较大，倒三叶叶宽受氮肥影响较小，说明氮肥处理对水稻叶片的影响主要表现在倒二叶叶长和倒一叶叶宽两个特性上。以水稻产量为因变量，叶片各形态特征为自变量进行逐步回归分析表明，倒二叶叶长、倒一叶叶宽和叶面指数（LAI）与产量建立的逐步回归方程达到了极显著水平（r=0.996 2**），说明倒二叶叶长、倒一叶叶宽和叶面指数对产量的作用较大。

关键词: 水稻;氮素;产量;上三叶;叶面积指数