Possible Contribution of Corticular Photosynthesis to Grapevine Winter Hardiness

Abstract

Numerous studies show that photosynthesis in non-foliar tissues contributes to plant productivity. Here, we demonstrate that in chlorenchyma tissues of lignified branches of grape vines, photosynthetic activity is maintained during winter and provide evidence that corticular photosynthesis could contribute to the plant’s freeze tolerance. In a collection of grape varieties that varied noticeably in freeze tolerance, a positive correlation between the maximum quantum yield of photosystem II in the wintering vines and the ability to survive harsh winter temperatures was observed. A more detailed comparison of two grapevine varieties differing in freeze tolerance showed that the vines of the more tolerant variety have more abundant corticular chlorenchyma with chloroplasts containing a better developed network of photosynthetic membranes, characterized by a higher photosynthetic pigments content, higher efficiency of both photosystems, and higher mobility of antennae complexes under the changing light intensity. In addition, we found that freezing temperatures induced more damage in vine samples when they were preliminarily treated with a specific inhibitor of photosynthetic electron transfer. The data obtained could be useful in the generation of freeze-tolerant grape varieties.