Abstract: The knowledge of dynamic change of leaf chlorophyll content is an important prerequisite for better understanding the featured carbon cycle as well as other ecological functions in desert ecosystems.Non-destructive rapid estimation of chlorophyll content is a prerequisite to dynamically monitor chlorophyll content,and it is an important research issue of vegetation remote sensing.In this study,a total of 86 spectral indices published previously were collected for assessing their capabilities of estimating chlorophyll content of assimilating shoots of Tamarix ramosissima,a constructive species in desert ecosystems.Three indices with simple structure and good performance,i.e.R₈₆₀/(R₅₅₀×R₇₀₈),1/R₇₀₀ and R₅₅₀,were selected,their determination coefficients (R²) were 0.49,0.47 and 0.40,and their root-mean-square errors (RMSE) were 2.40,2.45 and 2.59 μg·cm^-2,respectively.The validated errors of bootstrapping of the three indices were 2.47,2.53 and 2.67 μg·cm^-2 respectively.Our results indicated that these identified indices may be used for monitoring the dynamic change of chlorophyll content of T.ramosissima in arid land to a certain extent,it remains an important challenge to develop new better hyperspectral indices for estimating chlorophyll content of assimilating shoots.

Key words: vegetation remote sense, hyperspectral index, chlorophyll content, Tamarix ramosissima