Calcium localization with plant roots by electronprobe X‐ray microanalysis

The microdistributions of Ca and K within the roots of soybean and corn were determined by an electronprobe x‐ray microanalyser. In soybean plant, the highest concentration of Ca was found at the outer cell layers of the root. Little accumulation of Ca was found in the boundary region of the stele. K was more concentrated in the boundary region of the stele than in the outer cell layers of the root. In corn plant, Ca was highly concentrated at the endodermis but scarcely within the stele. K was equally concentrated both at the endodermis and within the stele. Ca at the outer cell layers of soybean root could easily be translocated, while that at the endodermis could not. K was translocated from both of the sites of its accumulation. On the basis of these facts, characteristics of the centripetal movement of Ca in root were discussed.