Studies on the Tolerance of Plants to Ammonium Nutrition1,2

Abstract

Bean, sweet corn, cucumber and pea plants were susceptible to ammonium toxicity when cultured on an ammonium source of N. Growth of plants was normal, however, when the pH of the nutrient solution was maintained near neutrality by the addition of CaCO 3 . The control of acidity was effective in altering the distribution of ammonium; ammonium accumulation in the shoot was lessened and accumulation of amides in roots was enhanced. A natural resistance to ammonium was exhibited by the onion plant since it did not accumulate ammonium in the leaves; however, the nonchlorophyllous bulb acted as an ammonium sink.