Effects on Zea mays Seedlings of a Strontium Replacement for Calcium in Nutrient Media.

When Sr replaced Ca in the nutrient medium, maize seedlings remain alive when seedlings in a Na-replacement for Ca died. In Sr, elongation of roots and shoots was inhibited; however, development of secondary root priraordia was stimulated, and differentiated xylem elements appeared near the root apical meristem. In the absence of external Ca in the nutrient medium, Sr, as compared to Na, did not appear to slow down the rate of loss of Ca from seedling roots, nor did it appear to allow for redistribution of Ca from older parts of the root to the root tip. It is concluded that Sr can replace part of the Ca ordinarily required by these seedlings. (auth)