Influence of sodium chloride on the growth and mineral nutrition of pepper cultivars

The response of four cultivars of pepper (Capsicum annuum L.), Yolo Wonder, HDA 103, HDA 174, and SC 81 to sodium chloride (NaCl) salinity was studied in hydroponic culture by comparing three different NaCl concentrations: 0 mM, 50 mM, and 100 mM. For all cultivars, growth was reduced when NaCl concentration in the growth medium increased. However, cultivar behavior as a function of the NaCl concentration was not homogenous. The HDA 174 displayed the best growth when NaCl concentration was high, while Yolo Wonder was the most sensitive to salinity. The SC 81 showed intermediate behavior since its growth was low at all treatment levels, but it reacted only slightly to increasing salinity. The analytical results showed that growth was very closely linked to the zinc (Zn) content of the blade: the best growth was observed when the percentage of Zn in the blade was low, whereas high Zn content was linked to sharp reduction in growth. The most tolerant cultivar, HDA 174, showed an original response: the sodium (Na) was strongly accumulated in the leaf blade, whereas the other cultivars tended to avoid Na accumulation. This corresponded to an adaptation observed for halophyte plants.