PROLINE APPLICATION ENHANCES GROWTH OF CHILLI BY IMPROVING PHYSIOLOGICAL AND BIOCHEMICAL ATTRIBUTES UNDER SALT STRESS

Salinity is a serious threat to crop production in Pakistan and all over the world. It imposes severe reduction in horticultural crop yield and production. Proline is reported to involve in salt tolerance in various crops. It was hypothesized that proline could ameliorate the salinity induced damages in physio-chemical attributes against salt stress. Therefore, a pot experiment was conducted to assess the role of foliar application of proline to improve the salt tolerance in chilli genotypes. Two chilli genotypes namely; Plahi and A-120 were grown under 50 mM NaCl saline condition. Various concentrations of proline (0.4, 0.6, 0.8, 1.0 and 1.2 mM) were applied as a foliar spray on one month old seedlings. Salt stress imposed negative impact on growth (Shoot and root length, plant fresh and dry mass), ionic (K+) and physiological (photosynthetic rate and transpiration rate) attributes in both the studied chilli genotypes except Na+ which increased under salinity stress. However, maximum reduction was observed in A-120 as compared to Plahi genotype. In contrast, foliar application of proline under salt stress conditions stimulated shoot and root length, plant fresh and dry mass, photosynthetic rate, transpiration rate and antioxidant enzyme (SOD and CAT) activities were noted under salt stress in both the genotypes. However, maximum increase was observed in Plahi genotype relative to A-120. Moreover, among all proline concentrations, 0.8 mM proved to be the best concentration regarding growth, physiological, ionic and biochemical attributes in both the genotypes.