Seed priming with cobalamin (vitamin B12) provides significant protection against salinity stress in the common bean

Abstract

Salinity is an important environmental factor that has a negative impact on plant growth. Availability of growth regulators plays a crucial role to enhance adverse effects of salinity. The effects of saline water irrigation and cyanocobalamin (vitamin B12) priming were evaluated on some growth parameters and biochemical attributes of common bean (Phaseolus vulgaris L.). The seeds were primed in various concentrations of vitamin B12 (0, 11, and 22µM). Ten seeds of each group were sown in plastic pots. All pots were placed into a growth chamber. Four weeks after sowing, salt stress treatment was initiated and nine of the pots were subjected to salinity stress by NaCl solution (75mM) daily. The remaining plants, as controls were irrigated with tap water. Effects were determined by leaf area, root and shoot length, root and shoot dry matter, antioxidant enzyme activity, protein content, chlorophyll and carotenoids, lipid peroxidation and proline accumulation. The results demonstrated that application of vitamin B12 provided significant protection against salinity stress compared with non treated plants. According to the outcomes, antioxidant enzyme activity, lipid peroxidation, carotenoid and proline accumulation increased due to NaCl stress while protein, chlorophyll and carotenoids decreased. Seed priming with vitamin B12 induced these stimulatory effects on all the measured parameters. Root protein and leaf carotenoid content were not affected by vitamin treatment under conditions of salinity stress. These results suggest that, vitamin B12 may have a critical role as an effective antioxidant and regulates osmotic balance thereby enhancing bean plant's resistance to salinity.