Effects of heavy metals on soil microbial community structure and diversity in the rice (Oryza sativa L. subsp. Japonica, Food Crops Institute of Jiangsu Academy of Agricultural Sciences) rhizosphere

Abstract

ABSTRACTWe performed a pot culture experiment to evaluate the effects of the heavy metals cadmium and chromium (Cd 1, 10 mg kg−1; Cd 2, 20 mg kg−1; Cd 3, 50 mg kg−1; Cr 1, 100 mg kg−1; Cr 2, 400 mg kg−1; Cr 3, 700 mg kg−1; control, without heavy metals) on the microbial community and carbon utilization diversity. Of 46 bacterial genera (relative abundance ratio of genera greater than 0.3%), 28 and 31 genera were significantly affected by the Cd treatments and Cr treatments, respectively. Soil containing 20 mg kg−1 Cd exhibited the highest relative bacterial abundance, bacterial community diversity and carbon utilization diversity. The relative abundance of Longilinea was significantly higher in the control soil than in heavy metal-treated soils at all sampling stages. The relative abundance of Pseudomonas was significantly higher in Cd 2 and Cd 3 soils than in the other heavy metal-treated and control soils. The relative abundance of bacteria and carbon source utilization ability were higher at the heading stage than at the maturing stage. Therefore, certain concentrations of heavy metals can improve microbial community structure and carbon utilization diversity.