Abstract
When applications of certain purines and pyrimidines enhanced the development or maintenance of cold hardiness, the content of water-soluble, trichloroacetic acid-precipitable protein and nucleic acids and tissue pH were higher in treated plants than in controls. The reverse was generally true when the treated plants were less cold hardy than the controls. In some instances, the purines and pyrimidines increased the content of these nitrogenous constituents in a nonhardy variety to a level equal to that found in untreated plants of a hardy variety.