Vol. 17 No. 2
Response of black gram to seed biopriming with facultative halophilic bacteria under salinity
Author(s): Y. NAGARAJU, MAHADEVASWAMY, GUNDAPPAGOL AND N. M. NAIK
Abstract: Under high salinity conditions, plant growth-promoting halophilic bacteria (PGPHB) can thrive and greatly encourage plant growth. The use of PGPHB is minimal and less discussed in sustainable agriculture and abiotic stress control. The current investigation focuses on improving the growth of black gram by inoculating with halophilic bacteria under salinity stress.Four PGPHB bacteria, viz., Bacillus safensis strain Lewis_Bac_3 (HB-5), Pseudomonas stutzeri strain MN1 (HB-13), Staphylococcus xylosus strain C5 (HB-18) and Pseudomonas sp. (GP-21: reference strain) were inoculated to black gram seeds to evaluate their plant growth-promoting ability at 4 dS m-1 and pH >8.5. An increase in root length, plant height and the number of branches reported in consortium treatment (T8) indicate that salinity did not affect black gram photosynthesis and nutrient absorption in consortium treatment. Corroborating evidence revealed higher nodulation and total Nitrogen and phosphorous content in the same treatment than control. Due to salinity stress, decreased blooming was reported in the control; conversely, consortium treatment showed 29.3 flowers/plant. A positive correlation with yield was demonstrated by the number of pods and seeds per pod of black gram. In addition, there also a strong association between pods per plant and the number of flowers per plant, nutrient content, and length of the root. The decrease in control plot yield was due to shoot and root development resulting from insufficient nutrients availability. In this study, we also found a positive correlation between % P in plants and yield. Hence, we conclude that PGPH bacteria help to reduce salt stress and significantly increase black gram growth and yield under mild salinity stress.
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