Physiological exegesis of growth parameters in Amranthus tricolor inoculated with Cd resistant bacteria

The aim of this study is to understand the ability of Bucillus halotolerance DSM 8802 (as Cd- resistant bacteria isolate) for enhancing cadmium (Cd) phytoextraction in A. tricolor and the interaction between them through growth traits (fresh weight FW, dry weight DW, length L for both root and shoot and leaf area LA) and Cd tolerance index (CdTI%) estimated for all measurement. Our results showed that Bucillus halotolerance improved plant growth of A. tricolor with rates (1.15 and 1.29 times) for root and shoot FW respectively, and (3.26 and 1.32 times) for root DW respectively at 30 mg/l Cd concentration. Shoot FW was significantly increased by (50 mg Cd compared to the same Cd concentrations only. Root and shoot lengths with inoculum were significantly enhanced by (1.49 and 1.14 times) respectively at a little Cd concentration, while LA was significantly uptrend to (1.23 times) at 50 mg/l Cd with inoculum from the same concentration of Cd without inoculum. Also, Accumulation of Cd in root and shoot inoculated was enhanced from (242.5 and 255.5 µg /gDW) to (304.75 and 266 µg /gDW) respectively at 50 mg/l Cd, also BCF was increased from (1.250 and 2.643) under only high Cd concentration to (1.644 and 2.747) for root and shoot of A. tricolor respectively. This study demonstrated that A. tricolor is a good accumulator model in phytoremediation, and Bucillus halotolerance DSM 8802 promoted growth and enhanced water relationships values, and improved physiology parameters of A. tricolr against Cd toxicity and increase removal, accumulation and phytoextraction Cd efficiency of A. tricolor and succeed in enhancing of phytoremediation combination with PGPB system.