菅原, 恩

SUGAHARA, Megumi

To find the salt tolerance mechanism, branches were cut off from the trees of common species used for landscaping, and drops of salt solution of high or low concentration were put on the surfaces of their leaves to measure of the amount of chlorine penetrating in to them by the Mohr's method. Obseravation was also conducted on the visible damage which appeared on the surfaces of the leaves. As a result, it has been found that the tree species examined can be roughly categorized into three groups as follows: (1) Even highly concentrated salt solution hardly penetrates in to the leaves and causes no visible damage: (2) Even a salt solution of low concentration can penetrates rapidly in to the leaves and causes damage immediately: (3) Highly concentrated salt solution can penetrates in to the leaves rather rapidly and causes damage whereas they suffer only slight by the low concentration of the solution, which actually penetrates gradually. These results suggest that, in all cases, the degree of damage is more or less dependent on the amount of chlorides which penetrate in to the leaves. It is also suggested that the chlorine penetration, and consequently the degree of damage caused, are affected by the age of leaves and that chlorine is likely to accumulate at the tip of a leaf more densely than at the base. In addition, the surfaces and cross section of leaves were observed by microscopes in order to investigate the effects of the texture of a leaf on the degree of chlorine penetration.