Carbohydrate Changes during Seasonal Cold Acclimation and Deacclimation in Phloem and Xylem of Vitis Species with Different Cold Hardiness Levels.

Here, two field-grown grape species including Vitis amurensis Rupr. ‘Shuangfeng’ and V. riparia × V. labrusca ‘Beta’ showed different survival capabilities after overwintering. Their shoots’ cold hardiness and associated physiological changes were analyzed during seasonal cold acclimation and deaaclimation to illuminate response mechanisms on low temperature. The fluctuations of cold hardiness were synchronized in the two species, but ‘Shuangfeng’ had a higher tolerance than ‘Beta’ to cold stress, which was consistent with the field performance. Leaves and shoots of ‘Shuangfeng’ reddened, responds quickly to the natural low temperature, while those of ‘Beta’ remained green during the same period. Perhaps owing to variations in the carbohydrate accumulations in different colored leaves, so the freezing tolerance of ‘Shuangfeng’ correlated with total soluble sugars in the phloem, while the starch in the xylem and phloem determined the ‘Beta’s tolerance. The timing and types of the accumulated carbohydrates may be responsible for the difference in the water status, energy accumulation and cold hardiness between the two grape species. [ABSTRACT FROM AUTHOR]