ASSOCIATION BETWEEN ASCORBIC ACID CONCENTRATION AND COLD HARDENING IN YOUNG WINTER WHEAT SEEDLINGS

Abstract

The ascorbic acid content of winter wheat varieties, germinated in the dark at various temperatures on the surface of moist vermiculite, was much higher at a hardening temperature of 1.5 °C than at higher temperatures of 5°, 10°, or 20 °C. There were no differences between the ascorbic acid contents of wheat grown at the three higher temperatures. Ascorbic acid content was dependent on the stage of development at all temperatures. At 1.5 °C, the ascorbic acid content increased during the first 6 weeks of growth (shoots about 15 mm) and then decreased rapidly. This variation in ascorbic acid content was closely associated with the increase and decrease in cold hardiness of wheat grown under similar conditions.Ascorbic acid content was highest in shoots, intermediate in roots, and lowest in the endosperm of wheat grown for 6 weeks at 1.5 °C.At hardening temperatures (1.5° and 3 °C) the more cold hardy winter wheat varieties had higher contents of ascorbic acid. At higher temperatures the differences between varieties were small. The ranking of varieties by ascorbic acid content could be influenced by relative stages of growth.Artificial cold hardiness was imparted to winter wheat seedlings by feeding them aqueous ascorbic acid solutions of adequate concentration. The ascorbic acid content of leaves required for artificial hardening appeared to be similar to that accumulated in sprouts hardened fully by growth at low temperature.