水稻不同叶位层物理结构与冠层反射光谱的定量研究

 研究了不同土壤水分、施氮条件下水稻冠层反射光谱与冠层生长特征（叶面积指数、叶片干质量和鲜质量）的量化关系。结果表明，不同层次叶面积指数、叶片鲜质量和叶片干质量与冠层光谱的相关性大小均为：L12345>L1234>L123>L12>L1，而顶部5张叶片的面积和生物量（干、鲜质量）对冠层特征反射光谱的贡献大小顺序为：L2>L1>L3>L4>L5，顶部2张叶片对冠层光谱作用最大。发现比值指数R(760,710) 与水稻叶面积指数呈极显著线性相关；而比值指数R(1650,1100) 与水稻地上部鲜质量和干质量均呈极显著幂函数相关关系。因此，比值指数R(760,710) 和R(1650,1100) 可分别用来定量反演水稻叶面积信息和地上部生物量信息。

Quantitative Study on Canopy Spectral Reflectance and Physical Structure of Leaf at Different Layers

The quantitative characteristics of canopy reflectance spectra and canopy growth parameters (leaf area index, fresh weight and dry weight of leaf) in rice under different soil water and nitrogen levels were analyzed. The correlation coefficients between reflectance spectra and leaf area, leaf fresh weight and dry weight of the first (L1), second (L2), third (L3), fourth (L4) and fifth (L5) leaf, L1-L2 (L12), L1-L3 (L123), L1-L4 (L1234) and L1-L5 (L12345) from the top were: L12345>L1234>L123>L12>L2>L1>L3>L4>L5, and the two leaves from the top contributed the most to canopy reflectance spectra. After elongation leaf area index was linearly related to ratio index R(760,710), and aboveground fresh and dry weight showed significant relations with ratio index R(1650,1100) in rice. The results indicated that the ratio index R(760,710) and R(1650,1100) could be good indicators of leaf area index and aboveground fresh and dry weight in rice.