Investigation of sulfur dioxide influence on canopy spectral characteristics at early growth stage of rice

Field experiment was laid out in a split plot design with three varieties of rice. Rice samples were exposed to sulfur dioxide at different concentrations inside fumigation chamber. After measurement rice canopy reflectance spectrum, leaves of rice canopy were sampled to analyze physiological characteristic. The investigation mainly focuses on four parts. (1) SO2 concentration was significantly negative correlation with pH and chlorophyll content (correlation coefficients R from -0.621 to -0.503). (2) Investigation on characteristics of spectral curves indicated that differences in SO2 concentration impacted the spectral reflectance especially on the green reflectance peak and red absorption dip. (3) Correlation analysis showed that the average reflectance (ρblue, ρgreen, ρred, ρnir) and DVI (ρred –ρgreen, ρgreen -ρblue, ρnir-ρred, ρnir-ρgreen, ρ680-ρ560 and ρ760-ρ560) were significantly different at the 0.001 level. Almost all DVI were significantly correlated with chb and cht at 0.05 level or above. (4) ρblue correlated significantly with soluble protein and MDA. pH had a very significant correlation with chlorophyll content. Almost all DVI were significantly correlated with pH. Vegetation indices ρblue, ρnir-ρred , ρgreen and ρ760-ρ560 were selected to estimate MDA content, chlorophyll b content , soluble protein and pH respectively. Cht was selected to estimate SO2 concentration and pH, respectively.