水稻叶氮量等生理参数的叶位分布特点及其与氮素营养诊断的关系

以氮素营养特性差异较大的3个品种为材料，研究了水稻不同生育期顶部4片展开叶中叶片总氮、叶绿素和游离氨基酸及叶鞘总氮含量的叶位分布特点。各生育期叶片和叶鞘总氮含量均以顶1叶最高，而游离氨基酸和叶绿素的最高含量叶位随品种和生育期而异。抽穗前游离氨基酸的最高含量叶位随品种和生育期变化较大，而抽穗后以顶1叶含量

Distribution of Leaf Nitrogen, Amino Acids and Chlorophyll in Leaves of Different Positions and Relationship with Nitrogen Nutrition Diagnosis in Rice

Field experiments with three rice genotypes,Baguixiang,Jinyou 253 and Liangyoupeijiu,were conducted to study the distribution of leaf nitrogen,free amino acids and chlorophyll in the leaves of different positions. The results showed that the contents of nitrogen,free amino acids and chlorophyll in the 4 top full expanded leaves,nitrogen in leaf sheath exhibited different spatial distribution patterns in response to the leaf positions. The first leaf revealed the highest contents of nitrogen in leaf blade and sheath at all growth stages,yet the leaf position with the highest contents of free amino acids or chlorophyll changed with genotypes and plant developmental stages. Free amino acid content in the first leaf was the highest after heading,but this tendency varied widely before heading. The highest chlorophyll content was in the first or second leaf after heading,while in the second or third leaf before heading. Contents of nitrogen,free amino acids and chlorophyll in 4 top leaves were well correlated with plant nitrogen content and thus could reflect the nitrogen nutrition status in rice plant. Among the 4 top leaves,the first leaf revealed the least coefficient of variance in nitrogen content,while the second leaf indicated the worst correlation to plant nitrogen content. Though both the third and fourth leaf showed large coefficient of variance in nitrogen content,the third leaf was proposed as the ideal leaf for nitrogen nutrition diagnosis in rice,because of the large difference in nitrogen content in the fourth leaves of rice population.