关键词: 高光谱, 黄化叶片, 无损检测, 病虫害防治, 桉树人工林

Abstract: Eucalypt yellowing disease is a relatively specific physiological disease, which has certain degree of suddenness and randomness. Timely detection and supplementation of nutrients could significantly reduce losses caused by the disease. Yellowing leaves (Chlorosis), non-diseased leaves (Chlorosis-Normal) and healthy leaves (Normal) of eucalypt were collected, and spectral characteristics of different leaves were determined by hyperspectral instrumentation. Discriminant analysis models were established based on PLS-DA and OPLS-DA methods, and discriminant effects were compared. Results showed that spectral reflection curves of different leaves showed the same trend, but reflection rates had obvious differences. Bands with significant differences were mainly reflected in near-infrared bands of 800-1 260, 1 400-1 720 and 2 000-2 400 nm. Original spectral reflection rates of leaves affected by disease were significantly higher than those of normal leaves. Logarithmic transformation could reduce redundancy of spectral data to a certain extent and highlight differences. Both linear discriminant analysis methods could identify potential yellowing leaves. Discriminant effect of Log-OPLS-DA was better with model R² of 0.91 and RMSE of 0.203. Combination of hyperspectral analysis technology and OPLS-DA had certain potentials of prediction and determination for eucalypt yellowing leaves.

Key words: hyperspectral, yellowing leaf, non-destructive testing, pest control, eucalypt plantation