Effect of Calcium and Nitrogen on Soybean(Glycine max)Root Fatty Acid Composition and Uptake of Linuron

Abstract

The effect of calcium and nitrogen level on the uptake of linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea] from nutrient solution by soybean [Glycine max(L.) Merr.] seedlings was determined and related to root membrane fatty acid composition. Calcium levels in the nutrient solution were 0.4, 4.0, or 8.0 mM and nitrogen levels were 4.0, 16.0, or 32.0 mM with the pH adjusted to 6.5. As calcium concentration increased, linuron uptake decreased. The reverse was true for nitrogen. These changes were not related to transpiration. Increasing calcium concentration increased palmitic acid and decreased linolenic acid in the plasmalemma of the soybean roots resulting in a greater degree of saturation. Nitrogen likewise increased the degree of saturation in the plasmalemma, but the effect was mainly seen in the balance between stearic and linoleic acids. In the mitochondria, however, the trends were inconclusive. High levels of linolenic acid were observed in the mitochondria regardless of treatment.