Effect of Salt Stress on Transpiration and Ion Distribution in Seedlings of Four Tree Species

Transpiration rate and ion distribution of pagoda tree, walnut, velvet ash and poplar seedlings treated by NaCl solution of 0, 50, 100, 200 mmol·L-1 were studied. The results showed that there were significant differences in the response to NaCl among the four tree species. Na+ exclusion capacity of pagoda tree was the largest among the four species. The Na+ exclusion capacity of velvet ash was less than that of pagoda tree. Salt excretion capacity of velvet ash was limited. Its salt-tolerance was bigger than that of walnut. Salt-stressed walnut seedlings could alleviate its ion damage by reducing its transpiration rate. Salt-treated poplar "zhonglin-46" stock was ion-damaged for its high transpiration rate. There was no difference among the four species in being free of Cl-1 compartmentation ability. The different Na+ tolerance was one of the reasons account for the different NaCl tolerance of four species.