Salinity-triggered modulation of osmolytes and antioxidant defence in Capsicum annuum L. cv. bullet during seed germination

In response to salinity stress, plants modulate the levels of organic and inorganic solutes to reduce osmotic potential and preserve cell turgor. In the present communication, we have assessed alterations in osmolytes, antioxidant enzymes, and markers in young seedlings of Capsicum annuum L. cv Bullet under different salt regimes. Salinity stress alters germination performance in Capsicum annuum L. cv. Bullet through coordinated changes in osmolyte accumulation and antioxidant defence. Seeds exposed to increasing NaCl concentrations (0–200 mM) during germination exhibited a marked modulation of compatible osmolytes, particularly proline and soluble sugars, indicating activation of osmotic adjustment mechanisms. Concurrently, reactive oxygen species levels increased, as evidenced by elevated hydrogen peroxide and malondialdehyde contents, reflecting enhanced oxidative pressure and membrane damage. Different osmolytes and antioxidant enzymes are altered differently to cope with the situation. This famous chilli cultivar showed better osmotic adjustment and modulation of antioxidant enzymes and non-enzymatic antioxidants, which also play a pivotal role in salt tolerance. The findings also showed that whereas extreme salt overwhelms these defense mechanisms, resulting in poor germination and early seedling growth in this chilli cultivar, moderate salinity triggers adaptive osmolyte buildup and antioxidant activation that help to partially alleviate stress during germination.