Tolerance of Honeylocust Seedlings to Soil-applied Salts1

Abstract

Abstract Salt tolerance of honeylocust (Gleditsia triacanthos inermis Willd.) was determined using 2 month-old potted seedlings salinized with 200 ml of NaCl, KCl and Na2SO4 at concentrations of 0.05N, 0.15N and 0.25N applied daily to soil. Leaflets of plants receiving Cl developed a tip and marginal necrosis while leaflets of plants receiving Na2SO4 were uninjured. Shoot dry weight of plants receiving NaCl and KCl (0.15N and 0.25N) were significantly lower than plants from control and all concentrations of Na2SO4 treatment Total soluble salts were not responsible for injury. Na had no adverse effect on growth although shoot Na levels were greater than 2% of dry weight in NaCl (0.15N and 0.25N) plants. Shoot Cl was a reliable index of the degree of salt injury, for the greater the tissue Cl, the more rapid the onset and the more severe the injury. Root Na and Cl levels were inconsistent and did not reflect the degree of injury observed. Honeylocust, although reportedly highly salt tolerant, was severely injured by exposure to Cl salts and this injury, correlated with shoot tissue analyses, suggested a specific ion effect.