For the purpose of supplementing the previous reports, special attention was focused on the distribution of chloride ion contained in a leaf-blade of rice and wheat plants relating with the leaf-burn symptom due to saline treatment.
The first observable effect produced by saline treatment was a slight burning at the tip of the leaf-blade and the burn symptom became progressively severer into the leaf-blade.
When the leaf-tip had been killed with the tip burn, the chloride content of the leaf-tip expressed as the dry weight basis was larger than that of the still-living part. With the progress of the visible symptom in a burned leaf, the greatest percentage of chloride ion was recognized in the "toxic" part between obviously injured part and living part in a leaf-blade, and in a entirely burned leaf, showing the severest injury, the basal part of the leaf-blade had the greatest amount of chloride ion.
From these results, it may be considered that the variation in the total chloride content of a leaf-blade which shows the same severity of burning is caused by the variable levels of the chloride content required to develop the visible symptom in each part of a leaf-blade. The water content as well as the chloride in a leaf-blade was also larger in the leaf-base, and the above resultsmay show one of the reason why the authors have insisted on the prensence of a critical concentration of chloride ion within the leaf-blade, connecting with the development of burn symptom.