The Relation of Cold Resistance to the Status of Phosphorus and Certain Metabolites in Red-Osier Dogwood (Cornus Stolonifera Michx.)

The process of cold acclimation in the winter hardy woody shrub Cornus stolonifera Michx. was studied in relation to changes in phosphorus status and certain metabolites. Plants were cold acclimated effectively under controlled conditions which combined shortening photoperiods and freezing temperatures. Metabolic changes under these conditions were similar to those which occur naturally in autumn. There was an extremely close relationship between cold resistance and the status of phosphorus; i.e. as hardiness increased inorganic P decreased and acid soluble bound P and total organic P increased. Starch decreased during acclimation while the simpler carbohydrates increased. These included glucose, sucrose, fructose, raffinose, melibiose, xylose, and stachyose in decreasing order of occurrence. Proteins increased while free amino acids generally decreased. The non-volatile organic acids in decreasing quantitative order included malic, succinic, quinic, tartaric, citric, and shikimic acids. Of these only shikimic acid increased during hardening. These biochemical changes are discussed in reference to current theories of cold acclimation in plants.