[Relationship between canopy reflectance and plant water status of wheat].

The study on the relationship between canopy reflectance characteristics and plant water status of wheat under different soil water and nitrogen levels showed that the water contents of canopy leaf and plant had a significant correlation with the spectral reflectance of 460-510, 610-680, 1480-1500 and 810-870 nm bands at different growth stages and that of 460-1500 and 560-1480 nm bands over the whole growth period. The correlation degrees of canopy leaf (CL), upper-layer leaf (UL) and lower-layer leaf (LL) water content with spectral index were in the order of CL>LL>UL. In addition, the water contents of canopy leaf and plant after jointing stage were negatively linearly related to the ratio index R(610, 560) and spectral index (R(610, 560)/ND(810, 610)), but positively correlated with the normalized difference index ((R810 - R610)/(R810 + R610)), indicating that spectral index (R(610, 560)/ND(810, 610)) could be a good indicator for monitoring water status in wheat plant.