Seasonal changes in soluble protein, nucleic acids, and tissue pH related to cold hardiness of alfalfa

Abstract

Summary Studies were undertaken to examine the association between the cold hardiness and nitrogen metabolism of plants of two alfalfa ( Medicago sativa L.) varieties differing in genetic potential for developing cold hardiness. Crowns and roots of the genetically hardy variety contained greater quantities of water-soluble, trichloroacetic acidprecipitable protein and nucleic acids than the crowns and roots of the nonhardy variety during the development and maintenance of cold hardiness. Moreover, the relationship between each of these nitrogenous constituents and cold hardiness was closer for the hardy variety than for the nonhardy variety. Seasonal trends for cold hardiness, content of water-soluble, trichloroacetic acid-precipitable protein, and content of the nucleic acids were markedly different for the two varieties. In response to changing environmental conditions in the fall, varietal differences were first noted for deoxyribonucleic acid content, then for ribonucleic acid content, and lastly in the water-soluble, trichloroacetic acid-precipitable protein content and cold hardiness of the plants.