炭疽病胁迫下的茶树叶片高光谱特征分析

试验以茶树不同炭疽病受害程度的叶片及健康叶片为材料, 室内测定其光谱反射率。结果表明, 炭疽病危害后, 茶树叶片的光谱值随发病程度的增加表现出有规律的变化, 740～1 000 nm波段的光谱反射率随病情加重呈现下降趋势; 而1 370～2 500 nm波段却表现出相反趋势。在742～974 nm和1 374～2 500 nm, 炭疽病受害程度与光谱反射率呈极显著相关。对光谱一阶微分特征分析表明, 在680～780 nm范围内处理间变幅最大, 有2个波段的一阶微分值与受害程度表现出极显著相关性, 分别为715～763 nm和776～778 nm波段。建立的炭疽病严重度诊断模型, 均达到极显著水平, 其中利用植被指数(Rg - Rr)/( Rg+ Rr)建立的模型精确度最高。

Analysis of the hyperspectral characteristics of tea leaves under anthracnose disease stress

The spectrum reflectance of single tea leaves infected by anthracnose was measured by ASD handy spectroradiometer. The results indicated that the spectrum characteristics of tea leaves infected by anthracnose had regular change with the increase of disease severity. Spectrum reflectance decreased significantly in 740-1 000 nm with the increase of the disease severity, whereas it increased in range 1 370-2 500 nm. There were significant correlations between disease severity and the spectrum reflectance in 742-974 nm and 1 374-2 500 nm. The characteristics of first derivative spectra in the diseased leaves and healthy leaves were changed, especially in 680-780 nm. There were significant correlations between the disease severity and first derivative spectral reflectance in 715-763 nm and 776-778 nm. The models for estimating tea leaf disease severity of anthracnose all reached significant level. The model constructed using vegetation index ( Rg- Rr)/( Rg+ Rr) could accurately invert the tea leaf damage degree.