Response of Selected Tree Species to Sodium Chloride1

Abstract

Six tree species were subjected to 0, 2000, 4500, and 7000 ppm NaCl in a hydroponics system. Flowering dogwood ( Cornus florida L.) and American sycamore ( Platanus occidentalis L.) showed the most foliar injury, followed by pin oak ( Quercus palustris Muenchh.), honeylocust ( Gleditsia triacanthos L.), eastern white pine ( Pinus strobus L.), and Japanese pagoda tree ( Sophora japonica L.). Height growth and dry weight increase of sycamore and dogwood, and dry weight of eastern white pine were significantly reduced by salt treatment. Dry weights of pin oak, Japanese pagoda tree, and honeylocust were unaffected. Chloride generally accumulated in higher concentrations in the leaves than in the stems, whereas Na showed the opposite pattern. Concentration of Cl in the stem was better correlated with species’ sensitivity to salt than were Cl and Na in the leaves, or Na in the stem. Although stem concentrations of N, P, Mn, Fe, B, and Zn did not change significantly with salt treatment in any of the 6 species, leaf concentrations of all of these elements did change significantly in one or more species. Manganese and Cu increased with salt in the leaves or stems of several sensitive species, but stayed stable in the tolerant species. Frequency of changes in concentrations of essential elements in response to salt occurred as often in the salt-tolerant as in the salt-sensitive species.