Abstract
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.
