In order to explain the highest concentration of Ca in the marginal part of taro corm we have to consider
that: (1) Ca is bound to the cell walls of thicker secretory cells,
which are more common in the marginal and lower parts, (2) Ca,
along with water, is transported to the corm from the roots connected to the corm exterior and (3) Ca is not mobile, it does not redistribute through the phloem