导数光谱在棉花农学参数测定中的作用探讨

AN APPROACH TO THE ACTION OF DERIVATIVE SPECTRA FOR AGRONOMIC PARAMETER DETERMINATION IN COTTON

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,分析并证实了棉花导数光谱对消除测量背景影响及寻找特征波长方面的作用。将导数光谱用于棉花农学参数的测定,发现棉花冠层和叶片光谱都存在红边位移现象,并且红边参数(红边位置、红边幅值、红边面积)与叶面积指数、鲜叶重、干叶重和叶绿素含量有显著相关,从而证明用棉花导数光谱测定它的某些农学参数的可行性。

The hyperspectral reflectance of the canopy and the third unfolded leaf from the top of the plants of two cotton varieties was measured with an ASD FieldSpec Pro FR^(TM) in the field and indoor at different growth stages of the plants. The concentrations of chlorophyll and carotenoid of the leaves corresponding the spectra were determined. The action of the derivative spectra for eliminating the influence of the measuring backgrounds and for determining some characteristic wavelengths of cotton was analyzed and confirmed. In the application of the derivative spectra to the determination of agronomic parameters of cotton, displacement of red edge was observed in the spectra of both the canopy and the leaves, and the red edge parameters (the position of red edge λ_(red), the slope of red edge Dλ_(red) and the area of red edge S_(red)) appeared significantly correlated with LAI, leaf fresh weight, leaf dry weight and chlorophyll content. Thus the results indicated the feasibility to determine some agronomic characters of cotton with its derivative spectra.