Cane Morphology and Anatomy Influence Freezing Tolerance in Vitis vinifera Cabernet franc

ABSTRACT

In 2014 and 2015, Ohio vineyards were exposed to multiple freeze events of –20 °C or lower, resulting in vine dieback, i.e., complete damage of above ground parts in Vitis vinifera. Grapevines that sustained dieback were rehabilitated for trunk replacement by training 1-year-old shoots with two distinct morphologies, based on internode diameter of large (L) and normal (N). This study evaluated the impact of cane morphology (L and N) in V. vinifera Cabernet franc on freezing tolerance (FT) of bud, phloem, and xylem tissues in relation to their respective anatomical structures and carbohydrate concentrations. Compared to N canes (7–9-mm diameter), L canes (10–15 mm) in Cabernet franc were considered vigorous and had the following morphological characteristics: long and heavy, with long and wide internode, and presence of numerous laterals. Furthermore, cane anatomy was also different with L canes having a significantly higher number of vascular transport units, xylem vessels, and phloem fibers than those in N canes. Freezing tolerance of buds and phloem was also different between the two cane types, with L canes being more cold sensitive than N canes, especially during fall acclimation and late-winter deacclimation. Sugar concentrations, however, were not different between L and N canes. These results suggest that cane morphology and anatomy play a significant role in affecting FT and the large and abundant anatomical structures of phloem and xylem contributed to the reduced FT of these tissues. In all practicality, this study suggests the best cultural practice for trunk replacement, and vine recovery should include the removal of the undesirable vigorous and cold sensitive canes during pruning.

KEYWORDS:

• Primary bud
• phloem
• xylem
• soluble sugars
• trunk replacement

Acknowledgments

We thank Joshua Blakeslee and Ann Channon for carbohydrate analysis, and Tea Meulia at the Molecular and Cellular Imaging Center for advice and assistance in sample preparation for anatomical studies. We also thank Martin Goffinet, Emeritus at Cornell University, for his advice on anatomical measurements and quantification. We are grateful to Bruce Williams and Logan Walter for vineyard and field maintenance.

Funding

This research was funded by the Department of Horticulture and Crop Science, USDA/NIFA Specialty Crops Research Initiative Award Number 2010-51181-21599 USDA-NIFA, and Ohio Grape Industry Program.

Additional information

Funding

This research was funded by the Department of Horticulture and Crop Science, USDA/NIFA Specialty Crops Research Initiative Award Number 2010-51181-21599 USDA-NIFA, and Ohio Grape Industry Program.