Effects of Salinity Stress on Growth and Biochemical Responses of Different Soybean Varieties

Soybean is a major source of plant protein and is also affected by the salt stress. In the present study, an attempt was made to assess the impact of salinity stress on different varieties of soybean viz. CO1, CO2, and CO (soy) 3 at different salt treatments (control, 50, 100, 150 and 200 mM). Increasing salt concentration resulted in a decrease in growth parameters, viz., shoot length, root length, fresh and dry weight of plants, and the number of leaves and branches per plant. CO (soy) 3 showed comparatively better tolerance variety and less damage compared to CO2 and CO1. CO (soy) 3 demonstrated the highest chlorophyll a (0.450 mg g ^− 1 FW), chlorophyll b (0.252 mg g ^− 1 FW) and total chlorophyll (0.702 mg g ^− 1 FW) even at 200 mM. Electrolyte leakage and malondialdehyde content increased with increasing salt stress in all varieties, indicating membrane damage and lipid peroxidation. These results demonstrate that CO (soy) 3 responded to salinity stress through enhanced osmolyte and antioxidant accumulation. EL (79%) and MDA content (43.40 nmol g⁻¹ FW) reached their highest level at 200 mM salt stress in the CO (soy) 3 variety. Proline content increased with salt stress, reaching its highest level at 200 mM (0.489 mg g⁻¹ fresh weight) in CO (soy) 3. Antioxidants, such as phenols (10.5 mg GAE g ^− 1 DW) and flavonoids (77.33 mg QE g⁻¹ DW) were also higher in CO (soy) 3 compared to CO2 and CO1.