Research On The Hyperspetral Response Mechanism Of Pine Plants Under Different Stress

Stress is a generic term which refers to the plants in adverse environments. For the pine forests, the common stresses are diseases, salt, drought and so on. Among these, pine wilt disease is confirmed as the most harmful to the pine trees. In this study, we analyzed on the different features of the pine trees under the circumstance of three prominent stresses based on the hyperspectral remote sensing data. The chlorophyll content of pine plants were simultaneously measured to determine whether the plant was under the stresses or not. Then, the kind of stress was further confirmed to establish the early monitoring models on the basis of the hyperspectral remote sensing. The results showed that:1) The chlorophyll content and the water content of pine plants which were charaterized by pine wilt disease and drought stress will gradually decrease with the deepening of the stresses, especially it will be sharpenedly reduced in the late period. However, the chlorophyll content and the water content of pines which affected by dieback fungus will gradually decrease with the deepening of the disease, but the change range isn’t obvious compared with other two types of stress in the late period.2)The original spectral reflectance which were influenced by different kinds of stresses have confirmed significantly different from the healthy ones in the late period. The absorption valley during the red bands and the reflection peak on the green band will gradually weakened with the deepening of stress influence. And in the late period they will completely disappeared. Moreover, the reflectance from the visible untill near infrared wavelength will gradually become a straight line. At the same time, the position of the red edge will gradually moved to the region of short wavelength, and the position of the yellow edge will gradually moved to the region of long wavelength.3) On analysis of a series of spectral parameters, we finally choose the RVI(810,450)to determine whether the masson pines were infected pine wilt disease on the early stage or not. And the FD652 was used to determine whether the black pines were infected pine wilt disease on the early stage.4) Firstly, the charateristics of chlorophyll content of pine plants under under different types of stress on various stages were analyzed. then, NDVI(810,680)was determined to quantify chlorophyll content of pine plants which infected by pine wilt disease and dieback fungus. However, the DVI(560,680) was determined to quantify chlorophyll content of pine plants which affected by drought stress.5) On analysis of a series of spectral parameters, we finally choose the FD629 to distinguish pine plants were infected with pine wilt disease or dieback fungus. And the FD672 was used to distinguish pine plants were affected by pine wilt disease or drought stress.