Spectral response of wheat (TritiZnm aestivum L.) leaves to copper stress

The spectral reflectance of wheat leaves changes when the plants are under the copper stress. The reflectance of wheat leaves with different Cu contents which are cultured with water solutions are measured using a ASD Fieldspec Spectroradiometer and an Integrating Sphere. Characteristic wavelengths, spectral dissimilar index, correction coefficient and fluorescence emission effect are analyzed using these data. The result shows that the spectral variation of TritiZnm aestivum L. leaves are caused by: (1) The excess of copper induced the inhibition of pigment synthesis and affected the development of the photosynthetic apparatus, which is one of the reasons why the reflectance increases in the visible region; (2) The decreased reflectance in the near-infrared, due to damage to leaf cell walls and mesophyll tissue. (3) The fluorescence effect is also an important factor that affects the reflectance spectra of leaves from 600 to 800 nm.