To gain a better understanding of environmental impacts on grapevines and the physiological regulation of acclimation we determined the effects of soil temperature (14°C or 24°C) between anthesis and veraison on growth, non-structural carbohydrates, cytokinins, abscisic acid and leaf function of potted Vitis vinifera cv. Shiraz. Plants of each regime were selected from two groups that had been grown in a glasshouse from three weeks prior to budbreak at an average soil temperature of either 13°C or 23°C. Soil temperature between anthesis and veraison affected utilization and restoration of root and trunk non-structural carbohydrates and changes in biomass of major plant organs. Soil warming promoted shoot growth via utilization of starch reserves, while soil cooling promoted starch storage in both the root and wood and shifted overall biomass partitioning to the roots. A change in soil temperature from warm to cool through flowering was also associated with reduced fruitset. Diurnal courses of photosynthesis, transpiration and stomatal conductance after fruitset were significantly affected by soil temperature. Phytohormones (cytokinin and abscisic acid) were measured in the xylem sap and leaves at fruitset and veraison. Differences between these two sample types during grapevine development highlight a phytohormone shift likely involved in post veraison fruit ripening. We conclude that soil temperature significantly affects grapevine growth and that the responses are mediated largely by an influence of temperature on mobilization of non-structural carbohydrates from the roots.
Field, S., Smith, J., Morrison, E., Emery, R. J. N., & Holzapfel, B. (2020). Soilk temperature prior to Veraison alters grapevine carbon partitioning, Xylem sap hormones, and fruit set. American Journal of Enology and Viticulture, 71(1), 52-61. https://doi.org/10.5344/ajev.2019.19038