Influence of Salt Stress on Different Pepper Genotypes: Ion Homeostasis, Antioxidant Defense, and Secondary Metabolites

Abstract

Salt stress, one of the most serious abiotic stresses, leads to a reduction in plant growth, development, and yield in many parts of the world. The purpose of this study was to determine the morphological, physiological, and biochemical salinity tolerance of nine local Turkish pepper genotypes and one variety. Greenhouse plants at the four-leaf stage were subjected to salt stress by adding a total of 150 mM NaCl to the nutrient solution over three days. The growth parameters, ion regulation, photosynthetic pigments, and antioxidative enzyme activities were investigated, as were the malondialdehyde, flavonoid, and phenolic contents. The growth parameters, K+ and Ca2+ contents, and total chlorophyll and carotenoid contents decreased under salt stress. Conversely, the Na+ and Cl– contents and the total flavonoid and phenolic compounds increased under salt stress in all of the genotypes; lipid peroxidation also increased in all genotypes. Antioxidant enzyme activities, however, increased more under salt stress in the tolerant genotypes than it did in the less tolerant plants. The results show that genotypes BIB-6 and BIB-8 were more salt tolerant than the other genotypes and have high potential as genetic material in future breeding programs.