关键词: 高光谱反射率, 叶绿素, 类胡萝卜素, 植被指数, 水稻, 发育时期

Abstract: The hyperspectral reflectances of the canopy, the first and the third unfolding leaf from the top and panicles of two rice varieties were measured by a ASD FieldSpec Pro FR TM in field and indoor under three nitrogen levels at different developmental stages.The concentrations of chlorophyll and carotenoid in leaves and panicles corresponding to the spectra were determined by biochemical method. The spectral differences were significant for the canopies and leaves of rice under different nitrogen levels, and the concentrations of chlorophyll and carotenoid of leaves increased along with nitrogen application increased. There were significant differences in the pigment concentrations of the rice leaves under different nitrogen levels. The spectral reflectance of the canopy was gradually getting smaller in the visible region and bigger in the near infrared region as the growth stages goes on before heading stage, but with reverse change after heading stage. There existed “blue shift” phenomena for the position of red edge of the spectra of canopies, leaves and panicles after heading stage. The concentrations of chlorophyll and carotenoid of leaves presented S-shape change. The concentrations of chlorophyll and carotenoid of canopies, leaves and panicles were very significantly correlative to the hyperspectral vegetation indices R₉₉₀/R₅₅₃, R₁₂₀₀/R₅₅₃, R₇₅₀/R₅₅₃, R₅₅₃/R₆₇₀, R₈₀₀/R₅₅₃, PSSRa (R₈₀₀/R₆₈₀), PSNDa[(R₈₀₀-R₆₈₀)/(R₈₀₀+R₆₈₀)][R denotes reflectance, number in subscript is wavelength (nm)] and the red edge position λ red. This indicated that these vegetation indices could be used to estimate the concentrations of chlorophyll and carotenoid of canopies, leaves and panicles of rice.

Key words: hyperspectral reflectance, chlorophyll, carotenoid, vegetation index, rice, developmental stage