Influence of rhizobacteria inoculation and exogenously applied salicylic acid on the contents of hydrogen peroxide and water in soybean (Glycine max L.) under drought condition

Abstract

Rhizobacteria and salicylic acid (SA) have an important role in the promotion plant growth and enhancement of crops resilience to abiotic stresses. The aim of the study was to evaluate the effect of rhizobacteria (Bradyrhizobium japonicum) inoculation alone and in combination with salicylic acid on soybean (Glycine max L.) plants under moderate drought stress condition. Therefore, a pot culture experiment was conducted to test whether SA application at concentration of 0.5 mM through foliar spray could protect the soybean cultivar Horboveanca to short drought stress based on growth and alterations in hydrogen peroxide and relative water contents (RWC). The control treatment received 70% water holding capacity (WHC) of soil, whereas moderate drought stress corresponded to 35% WHC. Results showed that water deficit decreased RWC and increased hydrogen peroxide contents in leaves. The efficiency of Bradyrhizobium japonicum in the presence of salicylic acid was higher compare to plants treated with rhizobacteria alone. Thus, experimental findings demonstrated that integrated use of rhizobacteria and SA alleviates the adverse effects of water deficit on growth and contributed to drought tolerance of soybean through increased relative water contents and decreasing accumulation of reactive oxygen species in plant tissues.