THE ACCUMULATION OF GLYCINEBETAINE DURING COLD-ACCLIMATION IN EARLY AND LATE CULTIVARS OF BARLEY

Barley plants are able to accumulate glycinebetaine (betaine) at high levels in their leaves in response not only to water and salt stress b ut also to cold stress. Such accumulation of betaine during acclimatio n to cold is associated to some extent with freezing tolerance in leav es of barley plants, as previously demonstrated with near-isogenic lin es that differed only in a single gene for the spring type of growth h abit (Plant, Cell and Environment 17:89-95, 1994). We now present evid ence that the levels of betaine accumulated during cold acclimation mi ght be associated with the earliness or lateness of the maturity of cu ltivars, namely, that late cultivars accumulate more betaine than earl y cultivars. Moreover, the grade of the vernalization requirement of t he cultivars seemed unlikely to be associated with the level of betain e accumulated during cold acclimation. However, the trait that control led accumulation of betaine during cold acclimation was not linked wit h the earliness or lateness of the maturity of cultivars. The higher l evels of betaine in the late cultivars might have resulted from co-sel ection for lateness of maturity and freezing tolerance, which is gener ally a requirement in the areas of Japan where such late cultivars wer e originally cultivated.