Hydroponic system using plant growth promoting bacteria (PGPB) - A dual approach to plant growth promotion and soil less agriculture

Plant Growth Promoting Bacteria (PGPB) are widely recognized as sustainable alternatives to synthetic fertilizers, herbicides, and pesticides in agriculture. However, their behavior in different cultivation systems remains unexplored. The present study was aimed at evaluating the growth of Lycopersicon esculentum cv. cerasiforme (cherry tomato) grown in a soil-based system and a hydroponic system with the use of PGPB. Three different bacterial strains, viz., Stenotrophomonas maltophilia strain V8, Enterobacter sp. strain V11, and Mesorhizobium muleiense strain V30, isolated from the vermicompost extract, were used for this study. The plants were evaluated for their biomass and morphometric and biochemical parameters over a period of 2 months. It was observed that plants grown in hydroponic systems displayed remarkable growth when compared to plants grown in soil. Among the tested strains, Enterobacter sp. strain V11 displayed better growth in terms of biomass accumulation, carbohydrate, and protein content, while Stenotrophomonas maltophilia strain V8 displayed maximum chlorophyll content. Two-way ANOVA demonstrated that there was significant improvement in the fresh weight of plants grown under hydroponic systems, whereas other morphological parameters did not differ significantly. Similar trends were observed in terms of photosynthetic efficiency and metabolic activity in PGPB-inoculated plants. Overall, findings suggest that hydroponic systems offer a favorable environment for plant growth, indicating that the substrate has an influence on the PGPB efficacy. This study emphasizes the favorable outcomes of the integration of PGPB into hydroponics. However, long-term studies over different plant species are necessary to confirm these findings.