| Abstract: | Plants have been grown in soils and nutrient solutions containingdifferent Ca/Sr ratios to find out whether there is any biologicaldiscrimination between calcium and strontium. When tomato plants are grown in nutrient solutions containingmolar Ca/Sr ratios from 2/1 to 4,000/1, the shoots do not distinguishbetween the elements, but the roots absorb strontium preferentiallyat low concentrations of this element. Since ion exchange resins show the same phenomenon, though toa less marked extent, this is believed to be a physico-chemicalrather than a biological effect. No chemical reagent has been found which can extract calciumand strontium from soils in the same ratio as plants. Ammoniumacetate extraction may give misleading results for the plant-availableCa/Sr ratios in the soil. Data for the Ca/Sr ratios in barleyand lucerne grown on soils containing ratios from 3/1 to 650/1emphasize this point. |
