Effect of Plant Growth Promoting Rhizobacterium on Uptake of Some Micronutrients by Corn in a Cd-contaminated Soil under Water Deficit Stress Conditions

Soils contaminated with heavy metals such as cadmium (Cd), mainly are poor in nutrients and microbial population. Water deficit stress can deteriorate the situation for healthy plant growth. Application of plant growth promoting rhizobacterium as bio-fertilizer can influence the availability of nutrients and improve the plant growth and health. For this reason, a greenhouse factorial experiment was conducted in a completely randomized design with three replications. Treatments consisted of two levels of Micrococcus yunnanensis bacterium (with and without bacterium), four levels of Cd (5, 10, 20, and 40 mg kg-1), and three levels of soil moisture regimes (100, 80, and 65% of field capacity). Results showed that increasing soil Cd contamination, resulted in reduction of shoots dry weight and total manganese (Mn) and zinc (Zn) uptake, while the soil inoculation with bacterium moderated the negative effects of Cd on the plant by increasing shoots dry weight and total Zn uptake. The main effect of water deficit stress on the shoot dry weight, and the uptake of iron (Fe), Mn, Zn, and copper (Cu) were significant and reduced these traits while the soil inoculation with bacterium increased shoot dry weight and uptake of Fe and Zn and mitigated negative effects of water deficit stress.