The effect of PGPR inoculation on the growth of wheat

Abstract

Many agricultural soils of Iran have high pH, resulting in low availability of Fe and Zn. The potentials of nonsymbiotic plant growth-promoting rhizbacteria (PGPR) for stimulating plant growth have been extensively used during recent decades. This experiment was carried out in growth chamber to evaluate the effects of siderophoreproducing Pseudomonads on the growth as well as Fe and Zn uptake of wheat. A randomized complete block design experiments was conducted using with Alborz genotype (an efficient phytosiderophore-producing bread wheat) treated with either 7NSK2 strain as a siderophore positive (sid+) or with MPFM1 mutant strain of the same isolate as a siderophore negative (sid-) treatments with three replications. The potentials of these strains for auxin production and phosphate solubilizing activity were evaluated by standard methods. The results showed that inoculation with sid+ strain increased dry matter production in shoots as compared with the control (sterile condition) or with sid - strain. Likewise, the concentration of chlorophyll a in leaves of sid+ and sid - treatments were 1.27 and 0.41 g mg-1 of fresh weight, respectively, and the concentration of chlorophyll b were measured to be 1.09 and 0.35 g mg-1 of fresh weight, respectively, indicating significantly more chlorophyll formation due to inoculation with sid+ as compared with sid -. The uptake of Fe by roots and its rate of translocation to the shoots were greater for the sid+ treated plants as compared with the sid - treated ones, indicating that siderophores increased the rate of Fe uptake by wheat. The effect of microbial inoculation on shoot Zn was not significant, but increased the concentration of Zn on roots compared with control. The results suggested that the siderophores of Pseudomonads may involve on increasing bioavailability of iron.