DIFFERENTIAL ABILITY OF TWO SOYBEAN VARIETIES TO TAKE UP FE59 FROM SOIL ADDED TO A NUTRIENT SOLUTION

Hawkeye and PI 54619-5-1 soybeans were grown in solution culture to which a small quantity of calcareous soil previously labeled with Fe/sup 59/ had been added as a source of iron and other micronutrients. The PI 54619-5-1 soybeans became chlorotic and contained a very low amount of Fe/sup 59/ in leaves. Differences in roots were less pronounced. When the two soybean varieties were grown together in the same solution the PI 54619-5-1 inhibited Fe/sup 59/ uptake by the Hawkeye, but the Hawkeye had no influence on Fe/sup 59/ in the PI 54619-5- 1. Hawkeye and PI 54619-5-1 soybeans were also grown in soil-solution mixtures containing Fe/sup 59/ with added organic chemicals that are believed to be commonly excreted by plant roots, and in mixtures with soils of varying pH. Citrate, flavin, and glycine inhibited Fe/sup 59/ uptake with Hawkeye soybeans. With PI 54619-5-1 soybeans, the uptake was so low that the chemicals caused no further inhibition. EDDHA resulted in large increases in Fe/sup 59/ uptake in roots and tops of both varieties, but that in leaves was twice as high foi the Hawkeye. Soils of high pH resulted in decre sed uptake of Fe/sup 59/ for both soybean varieties, but a high pH decreased Fe/sup 59/ uptake more with the PI 54619-5-1 soybean than with Hawkeye. (auth)