Heavy Metal in Rhizosphere Soil and Canopy Spectrum Analysis on Rhus Chinensis Mill

Abstract

In this paper heavy metals distribution in rhizosphere soil of Rhus Chinensis Mil is discussed. Relative soil stress index is proposed to describe the stress level of plant. The relationship between the Cu and Pb content in root, stem and leaf of Rhus Chinensis Mill was discussed, as well as the Cu and Pb content in soil and comprehensive stress index. 18 spectral parameters involving below 1000nm were extracted. Results show that soil from mine area contained more heavy metals than China red soil and background soil. It may attribute to the regional geochemical characteristics. Heavy metal content in most of the sampling points is higher than that in the background area, and the content are large differences in different sampling points. Referring to environmental quality standards, the heavy metals in majority soil samples are over the 2nd level but meet 3rd level, which can ensure agriculture production and plant growth. Heavy metal content in some soil samples exceed the 3rd level, and show a strong stress effect on plants. Heavy metals are quite different in leaves, stems and roots, indicating that leaves have certain enrichment. Heavy metals content in plants from polluted area is significantly higher than from the background area. RSSI had strong linear relationship with the Cu in roots and stems of Rhus Chinensis Mill, while has strong linear correlation with the Pb in roots (r2=0.607) and leaves (r2=0.666). CARI, GPR, GPA, LYE and other parameters changed significantly with the variation of soil stress parameters, but the change is nonlinear. These parameters can be employed in soil stress estimation.