Metabolic Changes Associated with Vernalization of Wheat. I. Carbohydrate and Nitrogen Patterns

Abstract

A spring wheat and an obligate winter wheat variety were each grown for 5 weeks in controlled environments at 2[degree] and 25[degree]. The threshold for flower induction in the winter wheat was 4-5 weeks at 2[degree]. There was an enhanced accumulation of the 5 carbo-hydrate fractions in both wheat varieties grown at 2[degree] compared to 25[degree]. Highly significant differences in the levels of sucrose, oligosaccharides, and starch were found between the spring and winter varieties grown at 2[degree]. The winter wheat seedlings grown at 2[degree] accumulated much more of these carbohydrates than the corresponding spring wheat. The carbohydrate patterns in both varieties grown at 25[degree] were nearly identical. The level of nitrogenous substances in the tissues grown at 2[degree] was much higher than in the corresponding tissues grown at 25[degree]. The only significant difference between the spring and winter varieties was in the soluble protein fraction. This fraction rose nearly 3-fold in the winter variety grown at 2[degree], whereas it remained nearly constant in the similarly grown spring wheat. Most of the changing chemical patterns observed in relation to the vernalization treatment appeared to be metabolic alterations associated with low temperature rather than alterations directly related with the vernalization response.