Free Amino Acids in Alfalfa as Related to Cold Hardiness

Abstract

Studies were carried out from 1957 to 1959 on the free amino acids, organic acids and sugars in Caliverde, Buffalo and Vernal alfalfa as related to winter hardiness. The alfalfa varieties which varied in winter hardiness, were planted in the early spring and roots were sampled in Aug., Oct. and Dec. The top 4 inches of the roots were washed, frozen in liquid air, finely ground, lyophilized and stored in a desiccator for analysis. A semi-quantitative analysis for amino acids, organic acids and sugars by paper chromatography of acetone-water extracts of lyophilized alfalfa roots did not show significant differences related to hardiness. Amino acid analysis by column chromatography showed a 20% increase in free amino acids from Aug. to Dec. in the roots of the most hardy variety. This was associated with a 31% increase in non-amino acid N over the same period. The non-hardy alfalfa variety showed little change in both N fractions as hardiness developed. Column chromatography revealed several unknown components which reacted with ninhydrin. Two of these were identified as the amino acids hydroxyaspartic and hydroxylysine.