棉花高光谱及其红边特征(I)

The Hyperspectra and their Red Edge Characteristics of Cotton(Ⅰ)

通过大田和室内试验,测定了2个品种的棉花冠层、完全展开倒1、3叶在不同时期的高光谱反射率及对应叶片的叶绿素、类胡萝卜素含量。结果表明:随发育期推移,棉花冠层光谱反射率在可见光范围降低,在近红外区域增高;叶片背面光谱反射率略高于正面,透射率小于反射率;叶面积指数、鲜叶重和干叶重与冠层反射光谱变量ρ800 ρ550、ρ800 ρ680、ρ680 ρ570之间存在显著相关;叶片叶绿素和类胡萝卜素浓度与其反射光谱变量ρ680 ρ570、ρ673 ρ640、ρ680 ρ550、PSSRa、PSNDa、RCh之间也呈显著相关。

The hyperspectral reflectances of the canopy, the first and the third unfold leaves from the top of two cotton varieties were measured in field and indoor at different stages. The concentrations of chlorophyll and carotenoid of leaves corresponding to the spectra were determined by biochemical method. The correlation between the pigment concentrations, leaf area index, above ground biomass and leaf mass and the spectral variables ρ800/ρ550? ρ680/ρ570?ρ673/ρ640?ρ680/ρ550?PSSRa?PSNDa and RCh of corn were analyzed. The hyperspectral reflectance were gradually getting smaller in the visible region and bigger in the near infrared region along with growth. The reflectance of back surface was slightly bigger than that of up surface, and the transmittance smaller than the reflectance for cotton leaves. The leaf area index, fresh leaf weight and dry leaf weight were significantly correlated to the spectral variables ρ800/ρ550,ρ800/ρ680 and ρ680/ρ570 of the canopy spectra. The concentrations of chlorophylla, chlorophyllb, total chlorophyll and carotenoid of leaves were also significantly correlated to the spectral variables ρ680/ρ570?ρ673/ρ640?ρ680/ρ550?PSSRa?PSNDa and RCh. This indicated that these spectral variables could be used to estimate the concentrations chlorophyll and carotenoid of leaves for cotton. 