Interspecific Differences in Sodium Accumulation and Requirement among Forage Crops

Abstract

Twenty species of forage crops including 9 varieties of Rhodes grass were grown in the same nutrient solution containing 0.5 mM Na for 2 weeks. Shoot Na concentration varied from less than 0.02% (sorghum, maize, and Sudan grass) to 1.07% (Kabulabula grass). The shoot/root ratio of Na concentration exceeded one in Rhodes grass, green panic, finger grass, Kabulabula grass, and Makarikari grass. The varietal differences in shoot Na concentration were much smaller than the interspecific differences. Ten species of grasses differing in their shoot Na content were grown in the nutrient solution with 0, 0.05, 0.1, I, 10, or 40 ppm of Na for 4 weeks. Dry weight of Makarikari grass, Coloured guineagrass, fall panic, Kabulabula grass, Rhodes grass, and Japanese millet remarkably increased with increasing Na concentration in the medium. On the other hand, sorghum did not appear to respond to Na. The foliar Na concentration of which the maximum dry weight was obtained varied as follows: Japanese millet, 0.013%; faU p...