Advances in viticultural management techniques have become increasingly important for mitigating the effects of challenging climatic conditions. The double-pruning technique is already widely used in Brazilian vineyards, enabling a shift of the harvest season from summer to winter. This shift allows key phenological stages, such as flowering, ripening, and harvest, to occur under milder temperatures and reduced precipitation. In contrast, the use of plastic coverings allows growers to maintain the conventional grapevine cycle while providing a physical barrier that protects the plants. Although both techniques are known and applied in some regions of the country, little information is available on their combined effects, particularly regarding plant physiology. Considering this gap, the present study evaluated the combined effects of double pruning and plastic coverings on the internal and external morphology and physiology of cv. Sauvignon blanc grapevines. The plastic covering prevented the direct incidence of rainwater on leaves and reduced the wash-off of applied fungicides. This led to lower disease incidence and fewer pesticide applications. Additionally, plastic covering reduced the photosynthetic photon flux density (PPFD) to levels close to the light saturation point of the grapevine, while also altering the light spectrum by attenuating UV-B radiation (280–315 nm). Together, these factors enhanced key physiological processes, including photosynthesis, transpiration, stomatal conductance, and chlorophyll accumulation. Leaf area is high in covered plants, and anatomical analyses revealed plastic responses in uncovered vines to excess light and UV-B exposure, such as thicker epidermal and palisade tissues and the deposition of epicuticular wax around stomata. However, these structural adjustments did not result in greater CO2 assimilation. Overall, this study demonstrates that the combination of simple management practices, as plastic covering, can improve and facilitate grapevine cultivation under challenging weather conditions, while also providing valuable insights into the physiological responses of the plant.
Daubermann et al. (Thu,) studied this question.