Effect of rhizosphere bacteria application on saline tolerant to proline and chlorophyll contents of cucumber

Efforts to expand agricultural cultivation to salinity soil are still experiencing many complications to get the optimum crop productions. Salinity-level on soil requires special technologies for crops to produce; one of the solutions is the application of rhizosphere bacteria to accelerate the plant growth. This study aimed to determine the optimum concentration of rhizosphere bacteria application to increase plant resistance on salinity. Bacterial isolates that were used in this experiment were isolated from exploration of Bacillus megaterium that had been proven on preliminary experiments that were capable of inhibiting nitrogen and IAA hormone production. The experiment was using combination randomized block design of non-saline soil and saline soil by controlling bacterial concentrations, 7.5 mL L^-1, 15 mL L^-1, 22.5 mL L^-1, and 30 mL L^-1. Parameters that were observed consist of leaf area, root length, plant dry weight, proline, chlorophyll content, number of fruit and fruit weight per plant. The results showed that application of rhizosphere bacterial with 15 mL L^-1 concentration increased chlorophyll content 14.1% higher than treatment without bacterial application. The bacterial application 30 mL L^-1 on saline soil increased the fruit weight per plant up to 41.4% higher than bacterial concentration of 7.5 mL L^-1.