Hyperspectral Estimation Models of Winter Wheat Chlorophyll Content Under Elevated CO2

Chlorophyll content is an important indicator of winter wheat health status. It is valuable to investigate whether the relationship between spectral reflectance and the chlorophyll content differs under elevated CO2 condition. In this open-top chamber experiment, the CO2 treatments were categorized into ambient (aCO(2); about 400 mu mol.mol(-1)) or elevated (eCO(2); ambient + 200 mu mol.mol(-1)) levels. The correlation between the spectral reflectance and the chlorophyll content of the winter wheat were analyzed by constructing the estimation model based on red edge position, sensitive band and spectral index methods, respectively. The results showed that there was a close relationship between chlorophyll content and the canopy spectral curve characteristics of winter wheat. Chlorophyll content was better estimated based on sensitive spectral bands and difference vegetation index (DVI) under both aCO(2) and eCO(2) conditions, though the accuracy of the models varied under different CO2 conditions. The results suggested that the hyperspectral measurement can be effectively used to estimate the chlorophyll content under both aCO(2) and eCO(2) conditionsand could provide a useful tool for monitoring plants physiology and growth.

Automated summary

The study found a close relationship between chlorophyll content of winter wheat and spectral reflectance under elevated CO2 conditions, with better estimation accuracy using sensitive spectral bands and difference vegetation index (DVI). Hyperspectral measurement can effectively estimate chlorophyll content and serve as a useful tool for monitoring plant physiology and growth under both ambient and elevated CO2 conditions.