The effect of mineral supply on the amino acid composition of plants

Abstract

Turnip plants have been grown under conditions of normal mineral nutrition and with deficiencies of nitrogen, phosphorus, sulfur, potassium, calcium or magnesium. The uncombined amino acids were separated from the protein fraction. The protein fraction of the leaves was analyzed for constituent amino acids. It was found that there were considerable differences in protein level between deficient and normal leaves but that the relative composition of the protein fraction was only slightly affected. The non-protein amino acids were profoundly influenced by mineral nutrition. The differences in amino acid concentrations suggested that the lack of various macronutrients affected the metabolism of amino acids in many ways.