棉花高光谱及其红边特征(Ⅱ)

The Hyperspectral and Their Red Edge Characteristics of Cotton—Ⅱ

通过大田和室内试验,测定了2个棉花品种的冠层、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:棉花冠层光谱红边具有“双峰”和“红边平台”现象,且红边位置λ_(red)位于695～720nm之间,红边幅值Dλ_(red)和红边面积S_(red)有“红移”和“蓝移”现象;叶面积指数、鲜叶重和干叶重与冠层光谱红边参数λ_(red)、Dλ(red)、S_(red)之间存在显著相关,叶片叶绿素和类胡萝卜素含量与其反射光谱的λ_(red)、Dλ(red)、S_(red)也有显著相关。

The hyperspectral reflectances of the canopy, the first and the third unfold leaves from the top of two varieties of cotton were measured by a ASD FieldSpec Pro FRTM in field and indoor in different stages. The concentra- tions of chlorophyll and carotenoid of leaves corresponding to the spectra were determined by biochemical method. The correlation between the pigment concentrations, leaf area indices, above ground biomass and leaf mass and the red edge parameters of corn spectra were analyzed. There are 'two peak' and 'platform of red edge' phenomena for the red edge of canopy spectra of corn. The position of red edge λred are between 695nm and 720nm. There were 'red shift' and 'blue shift' phenomena for the slope of red edge Dλred and area of red edge Sren for the canopy spectra. The leaf area indices, fresh leaf mass and dry leaf mass were significantly correlative to the red edge parameters λred, Dλred and Sred of the canopy spectra. The concentrations of chlorophyll-a, chlorophyll-b, total chlorophyll and carotenoid of leaves were also significantly correlative to λred,Dλred and Sred. This indicated that the red edge parameters λred,Dλred,Sred could be used to estimate the leaf area indices, fresh leaf mass and dry leaf mass and parameters λred and Dλred used to estimate the concentrations chlorophyll and carotenoid of leaves for cotton.