Abstract
Bromide accumulation by excised roots of rice at different O2 pressures is similar to that of barley and tomato roots. Under anaerobic conditions barley and rice roots with attached shoots accumulate appreciable amts. of bromide, while intact tomato roots do not accumulate. Seedlings were transferred to loam and clay soil cultures, and grown under conditions of drainage and submergence. Submergence is lethal to the tomato, limits the growth of barley, and improves the growth of rice. Plants were grown in water culture with continuous root exposure to air, N2, and CH4. Root aeration improves tomato growth considerably, barley slightly, and does not affect rice. N2 reduces tomato growth about 90%, barley by 45%, and rice is not affected. CH4 is lethal to tomato, reduces barley growth by 60%, and increases rice root growth 70% more than the unaerated control. Under anaerobic root conditions nitrate nutrient salts are not a significant source of respiratory oxygen.