Effect of plant growth promoting (PGP) and arsenic-resistant isolates on Physiological characteristics and macronutrients concentration of Mentha peparata L. in a arsenic-polluted soil

In order to perform this research, a greenhouse experiment was conducted in a completely randomized design with three replications. Treatments were involved: inoculation of Mentha peparata L. with 5 plant growth promoting (PGP) and arsenic-resistant isolates and control (without use of inoculant). Results revealed that inoculation of Oregano with superior isolates had significant effect on proline concentration. The greatest accumulations of proline (0.23 µg g-1FW) was observed in plants inoculated with AHG-6 isolate. The application of PGP isolates significantly increased chlorophylla, b, total chlorophyll content, chlorophyll index and carotenoids proportions compared with control. The inoculation of Mentha peparata L with PGP isolates has no significant effect on the plant phosphorus concentration. The utilization of all PGP microorganisms notably propagated the shoot magnesium concentration compared with control. Whereas only AHG-5 and AHG-6 significantly increased the root magnesium concentration. Regarding calcium and potassium, the use of PGP isolates augmented their concentration in the root and shoot, although there was no significant between some treatments and control The utilization of all PGP microorganisms notably propagated the shoot magnesium concentration compared with control. Whereas only AHG-5 and AHG-6 significantly increased the root magnesium concentration. Regarding calcium and potassium, the use of PGP isolates augmented their concentration in the root and shoot, although there was no significant between some treatments and control.