Influence of Plant Growth Promoting Rhizobacteria (PGPR) on the Growth and Yield of Sunflower (Helianthus annus L.) Under Salt Stress

Abstract

Phytoremediation techniques include phyto-de-salinization, phytodegradation, phytoextraction, phyto-filtering, and phyto-volatilation. The phytoremediation technique is considered a promising method to remediate saline soils. The study was conducted with two concentrations of saline soil (50 and 100 mM) with one control, followed by treatment of two isolates (Azospirillum brasilense and Pseudomonas fluorescence). The experiment was conducted in a randomized complete block design using two hybrids (Hysun-33 & Hysun-39). The inoculation of Azospirillum brasilense increased the total biomass production, flowering characteristics, and yield of sunflowers. The study parameter’s result showed that using plant growth-promoting rhizobacteria (PGPR) gives successful vegetative growth with good flowering characteristics and induced salt tolerance in sunflowers. So, bacterial isolate Azospirillum brasilense conformed to better vegetative growth and flowering than isolates of Pseudomonas fluorescence. There was an increase in antioxidants, e.g., catalase, peroxidase, ascorbate peroxidase, and proline content, and a decrease in hydrogen peroxide content of plants by inoculation of Azospirillum brasilense and Pseudomonas fluorescence. Decreased growth at higher salinity levels causes hyper-ionic and hyperosmotic stress and can lead to plant demise. From the results obtained, it could be recommended that Azospirillum brasilense be used to induce salt tolerance in sunflower (Helianthus annus L.) cv. “Hysun-33” under high salinity levels increases vegetative growth, flowering character, yield, and quality of sunflower.