Glutamine in the Tomato Plant

Abstract

Tomato plants grown in sand cultures that provided N in the form of ammonium salts stored glutamine, particularly in the stems, in quantities, reckoned on the gm. per plant basis, of from 2 to 3 times as great as control plants provided with N in the form of nitrates. They likewise contained somewhat more than twice as much free ammonia as the control plants. Growth was, however, much more luxuriant on the nitrate solutions. The identity of the amide stored by the plants on ammonium salts was confirmed by isolation. Of the amide N of these plants 63% was accounted for as pure glutamine, 5.5% as the equivalent glutamic acid which was isolated as the hydrochloride, and 5.6% as pure asparagine; in all 74% of the amide N was accounted for as crystalline products of demonstrated purity. Glutamine can therefore serve as a means for the detoxification of ammonia in a mature plant, and indeed plays the chief part in this connection in the tomato plant.