Water relations of drought-resistant and drought-sensitive wheat cultivars sprinkled with saline water

Abstract

Water potential, osmotic potential, turgor potential, and stomatal resistance were measured on leaves of a drought-sensitive (‘Ponca’) and a drought-resistant (‘KanKing’) cultivar of winter wheat (Triticum aestivum L.) treated with foliar applications of NaCl to determine the effect of salt on the water status of two cultivars varying in drought resistance. Plants were grown under controlled conditions in soil, which was watered or allowed to dry. Water potential of the soil was determined. Given an ample water supply, water potential and osmotic potential of leaves of both cultivars with NaCl were lower, and stomatal resistance was higher, than without NaCl. The combination of salt and drought killed both cultivars, but the turgor potential of the drought-sensitive cultivar with the two stresses reached zero before that of the drought-resistant cultivar. Under limited water supply, both cultivars with foliar applications of salt extracted more water from soil than they did with no salt, and the drought-resistant cultivar took up more water than did the drought-sensitive cultivar. The drought-resistant cultivar with foliar NaCl maintained a higher turgor potential and extracted more water from the drying soil than did the drought-sensitive cultivar with foliar NaCl, suggesting that the drought-resistant cultivar was also more salt tolerant.