Effects of Nitrogen on the Nitrogenous Fractions of Ananas comosus (L.) Merr.

Abstract

A. comosus grown in high-N cultures (140 mg. per litre of nutrient solution) absorbed five times as much N as in low-N (2.8 mg.), whether NO3 or NH4 was used. Total N and protein-N were 3-4 times, and soluble N was 4-8 times greater in high-N than low-N cultures. Soluble orgainc-N was higher in the green parts of the leaves, and higher with NH4 than with NO3. Protein-N generally correlated to mono-amino-N and basic-N. The results suggest a continuous formation of amino-N from proteins undergoing normal hydrolysis in the cell, or the synthesis of proteins by condensation of amino acids in cultures supplied with either adequate or inadequate inorganic-N. Excess of N supplied as NH4 or NO3 may cause accumulations of soluble organic N fractions produced by enzymatic synthesis from ammonia with carboxylic acids, and similar to those presumably released from protein breakdown.