Screening and evaluation of indigenous halo-tolerant microbes for salt stress alleviation in celery (Apium graveolens)

Abstract

Salinity is one of the major environmental threats which damages growth and productivity of the plants. Microbial assistance in such stressful environment is well recognized. Here in this study, we isolated indigenous microbes and investigated their rescuing potential in celery plants grown under salinity stress. Celery is a widely consumed plant in salads. Plants were cultivated under varying levels (5 & 10% in aqueous solution against control) of salinity in the greenhouse with inocula of two isolated strains of rhizobacteria (RB) which were screened from locally collected soil samples. Data (chlorophylls, carotenoids, anthocyanins, fresh and dry weights of plants, and lengths of root and shoot) were collected and analysed using SPSS. Biochemical isolation of the rhizobacteria was also performed. Plants inoculated with the isolated rhizobacterial strains indicated a statistically significant relief to the stressed plants which resulted in more chlorophylls’ (a, b & total), carotenoid and anthocyanin contents that were at par with control. Post inoculation elongation of root and shoot as well as fresh and dry matter accumulations were enhanced significantly. RB 20 indicated statistically significant relief to the plants compared to RB 10. Bacterial strains screening results showed that strains RB 6 & RB 20 proved their positive relieving strengths in the tests of indole synthesis, siderophore production, phosphorus solubilization, casein hydrolysis, catalase activity, citrate biosynthesis, gelatinase biosynthesis, H 2 O 2 production, motility test, osmotic regulation potential and starch hydrolysis. Hence, these indigenous microbes might be helpful in assisting celery plants grown under salinity conditions.