Putrescine, Spermine and Spermidine Mitigated the Salt Stress Damage on Pepper (Capsicum annum L.) Seedling

In order to evaluate the effects of polyamines on plant growth, physiological and biochemical characteristics of pepper seedlings grown under salt stress (0, 50 and 100 mM NaCl), putrescine (Put), spermine (Spr) and spermidine (Spd) were foliarly applied to the seedlings under controlled greenhouse conditions. The effects of polyamines on plant height, number of leaves, stem diameter, chlorophyll reading value (CRV), stoma conductance (SC), tissue electrical conductivity (TEC), leaf relative water content (LRWC), enzyme activity of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) of pepper seedlings were significant under salt stress. As salt concentration increased, plant height, stem diameter, number of leaves, CRV, plant and root fresh and dry weight, and LRWC lowered but an increase in TEC occurred. However, polyamine treatments improved the parameters investigated under salt stress. In the study, it has been determined that the negative effects of salt stress can be mitigated with exogenously polyamine applications to the pepper seedlings.