Changes in sugars, osmolytes and antioxidants on exogenous application of Validamycin A, PPFM and KCl in black gram under drought stress

Abstract

Black gram (Vigna mungo L.) is a popular pulse crop that is seriously affected by drought stress. A study was conducted to explore the changes associated with the carbohydrates, osmolytes and antioxidants and the associated drought tolerance in black gram with exogenous application of Validamycin A, Pink-pigmented facultative methylotrophic bacteria (PPFM) and Potassium chloride (KCl). The experiment had eight treatments: Control (C), Validamycin A (VM-A), PPFM, KCl, drought stress (DS), DS+VM-A, DS+PPFM, and DS+KCl. The highest trehalose contents were observed in DS+VM-A (173.69 μg/g) and DS+PPFM (175.12μg/g). DS+PPFM treatment had highest starch (37.02 mg/g) and sucrose (5.70 mg/g) contents. Fructose was higher in DS+PPFM and DS+KCl treatments. Treatments VM-A, PPFM and DS+PPFM showed a higher accumulation of fructans. The proline content ranged between 4.8 and 11.22 μM/g. Treatment DS+KCl exhibited higher carotenoids (8.51 μg/g) whereas DS+PPFM exhibited higher tocopherol content (26.02 μg/g). Though root biomass was affected by drought stress, exogenous application of Validamycin A significantly increased root biomass.