Abstract
1) In plants of less resistant to acidity leaves are rich in Ca% than root, stem and leaf sheath. 2) Ca% in stem and leaf-sheath showed highly negative correlation with the tolerance of crops to soil acidity when extracted by acetie-acid ; and it showed correlation with the amount of pectic-acid % or absorptive power of cytoplasmic protein. 3) In the root of crops, Ca% was apt to be influenced easily by varying Ca concentration or pH-value of the solution. In the less resisting plants, Ca% in acetic-acid generally decreased when cultivated in acidic solution, and this response come also from the character of cytoplasmic protein; These results may be due to the fact that, in less-resisting plants, the decrease of pH value causes the decrease of negative charge in protein and therefore Ca becomes less absorbable and is apt to be released easily. 4) In the crops whose lime requirements are large, their cytoplasmic proteins have high Ca-absorbability and may have propably large negative charge.
