EVALUATING EFFICACY OF PLANT GROWTH PROMOTING RHIZOBACTERIA AND POTASSIUM FERTILIZER ON SPINACH GROWTH UNDER SALT STRESS

Soil salinity is a major constraint for crop production as it negatively impacts the supply of nutrients and produces ethylene that hampers crops productivity. Several studies have been conducted so far to devise robust strategies for alleviation of soil salinity stress on crops. Inoculation of plant growth promoting bacteria (PGPR) is one of the potential strategy to decrease salinity stress on the plants. The PGPR can produce 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase which decreases stress of ethylene generated by salinity. On the other hand, improving potassium (K) uptake is also an effective strategy to minimize the negative effects of salt stress on crops. Therefore, a pot study was conducted with co-application of two pre-isolated ACC deaminase producing PGPR (i.e. Bacillus amyloliquefaciens and Alcaligenes faecalis) with half (HRK) and full recommended dose of K (RK) fertilizer in spinach (Spinacia oleracea) under salt stress (control = 3.0 and 5.0 dS m(-1)). Co-application of B. amyloliquefaciens + RK significantly enhanced leaf and root fresh and dry weights of spinach. Maximum significant improvement in chlorophyll a (93%), chlorophyll b (50%), total chlorophyll (76%), K concentrations in leaf (70%) and root (60%), and reduction (26%) in leaf electrolyte leakage validated the effectiveness of B. amyloliquefaciens and A. faecalis with RK to mitigate salt stress. It is concluded that both B. amyloliquefaciens and A. faecalis with RK can alleviate salt stress in spinach.