Effect of biopriming with Enterobacter strains on seed germination and seedling growth of tomato (Solanum lycopersicum L.) under osmotic Stress.

Abstract

A study was conducted to evaluate the effect ofseed treatment with bacterial strains ofEnterobacterspp.on seed germination and seedling growth of two tomato(Solanum lycopersicumL.) cultivars (cv. Arka Meghali andcv. Pusa Ruby). The cultivar Arka Meghali is recom-mended for rainfed conditions, while cv. Pusa Ruby isgrown under irrigated conditions. Seeds were treated withosmotolerant plant growth promoting bacterial strainsbelonging to the genusEnterobacter(P-39, P-41 and P-46),for a period of 24 h and subsequently incubated at 25°Cunder different mannitol induced osmotic stresses (0,-0.2,-0.4,-0.6,-0.8,-1.0 MPa). Seed treatment with bac-terial strains influenced the germination and seedling vig-our index of both cultivars as compared to the untreatedand hydro-primed seeds, up to-0.6 MPa. The response ofEnterobacterstrains to water stress was better in cv. PusaRuby as compared to cv. Arka Meghali as indicated byhigher germination percentage and germination rate. Theseeds of both cultivars treated withEnterobacterP-39performed better under osmotic stress (up to-0.6 MPa incv. Arka Meghali and-0.8 MPa in cv. Pusa Ruby), indi-cating the significance of this strain as compared to otherbacterial strains studied. The bioprimed seeds that failed togerminate at osmotic potentials beyond-0.4 MPa, whentransferred to water (0 MPa), recorded improved germi-nation and seedling vigour. These results indicated that thetreatment of seeds with osmotolerant plant growthpromoting bacterial strains improved the germination andenhanced seedling growth under osmotic stress conditions.