Plant growth promoting rhizobacteria mitigate deleterious combined effects of salinity and lime in soil in strawberry plants

Abstract

The effects of Kocuria E43, Alcaligenes 637Ca and Pseudomonas 53/6 on combined lime and salinity stress in the soil were evaluated on strawberry cv. ‘Sweet Ann’. The results of the experiment showed that yield, average number and weight of fruit, leaf area, nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) and sodium (Na) content of leaves, SPAD, stomatal conductance, membrane stability, protein and proline contents, hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents and catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX) activity were considerably affected by rhizobacterial inoculations in strawberry plants. There was a remarkable enhancement in fruit weight, number and yield, leaf area, macro elements contents of leaves, SPAD, stomatal conductance, protein and proline contents and CAT, SOD and APX activity. On the other hand, the sodium content of leaves, membrane permeability, H2O2 and MDA contents were considerably reduced by rhizobacterial treatment. The 637Ca had the highest yield per plant (120.4 g), while the lowest value was found in the control (89.9 g). Average increases in N, P and Ca contents in the leaf were obtained from rhizobacterial root inoculations of 16%, 35% and 32%, respectively. The lowest stomatal conductance was found in the control (67 mmol/m2s), while E43 + 53/6 had the highest (384 mmol/m2s). The highest CAT, SOD and APX activity were obtained from 637Ca + 53/6 (563 µmol min−1 mg−1 FW), E43 + 637Ca + 53/6 (399 µmol min−1 mg−1 FW) and E43 + 637Ca (31.91 µmol min−1 mg−1 FW), respectively. These results suggested that the 637Ca, E43 + 53/6 and E43 + 637Ca + 53/6 treatments may be effective in reducing the negative impacts of combined salinity and high calcareous in soil.