Uncovering the effects of kaolin on balancing berry phytohormones and quality attributes of Vitis vinifera grown in warm‐temperate climate regions

Abstract

BACKGROUND The application of kaolin particle film is considered a short‐term strategy against several environmental stresses in areas with a Mediterranean‐like climate. However, it is known that temperature fluctuations and water availability over the season can jeopardize kaolin efficiency in many Mediterranean crops. Hence, this study aims to evaluate the effects of kaolin foliar application on berry phytohormones, antioxidant defence, and oenological parameters at veraison and harvest stages of Touriga‐Franca (TF) and Touriga‐Nacional (TN) grapevines in two growing seasons (2017 and 2018). The 2017 growing season was considered the driest (−147.1 dryness index) and the warmest (2705 °C growing degree days) of the study. RESULTS In 2017, TF kaolin‐treated berries showed lower salicylic acid (−26.6% compared with unsprayed vines) and abscisic acid (ABA) (−10.5%) accumulation at veraison, whereas salicylic acid increased up to 28.8% at harvest. In a less hot season, TN and TF kaolin‐treated grapevines showed a twofold in ABA content and a threefold increase in the indole‐3‐acetic acid content at veraison and lower ABA levels (83.8%) compared with unsprayed vines at harvest. Treated berries showed a decreased sugar content, without compromising malic and tartaric acid levels, and reactive oxygen species accumulation throughout berry ripening. CONCLUSION The results suggest kaolin exerts a delaying effect in triggering ripening‐related processes under severe summer stress conditions. Treated berries responded with improved antioxidant defence and phytohormone balance, showing significant interactions between kaolin treatment, variety, and developmental stage in both assessed years. © 2021 Society of Chemical Industry.

Sunscreen Based on Dicarboxylic Acid Salts Applications to Blueberries (Vaccinium corymbosum L.) Plants: Effects on Water Stress Tolerance and Productivity

“…Some authors reported no effect or even an increase in net assimilation and stomatal conductance, while other researchers observed a reduction [42,43]. Based on this, the effectiveness of radiation-reflecting products in improving leaf resilience when subjected to severe environmental conditions, mainly through gas-exchange assessment, can be significantly changed according to the variety, water status, and stress severity [37]. The effects of these products suggest the modulation of indole-3-acetic acid (IAA), salicylic acid (SA), and abscisic acid (ABA) levels in crops cultivated in Mediterranean-type climates [37,44,45].…”

“…Thermal and water stresses are increasingly frequent in the Mediterranean production area during summer, limiting productivity and berry quality [8,33,34]. The exogenous foliar application of radiation-reflecting products has proven effective in mitigating the negative impacts of these abiotic stresses in grapevine and other fruit crops [15,[34][35][36][37]. However, to our knowledge, there is little available information about sunscreen foliar applications to mitigate thermal and water stress conditions in blueberries.…”

“…However, to our knowledge, there is little available information about sunscreen foliar applications to mitigate thermal and water stress conditions in blueberries. Some authors have proposed that radiation-reflecting products could be used as additional tools to save water in several species, such as olives, clementine, tomatoes, and grapefruits [37][38][39][40][41]. However, there is an ongoing debate on its effects on gas exchanges, and mechanisms of action are not yet completely understood [35].…”

Effect of Agronomic Techniques on Aroma Composition of White Grapevines: A Review

“…It is in this context that proper agronomic management together with the introduction of innovative and sustainable techniques assume great importance [24][25][26]. The present review paper examines multiple agronomic and canopy management techniques aimed at improving the aromatic quality of some of the most important aromatic white grape varieties grown all over the world.…”

Effect of Shading Nets on Yield, Leaf Biomass and Petiole Nutrients of a Muscat of Alexandria Vineyard Growing under Hyper-Arid Conditions

“…By consequence, short-term adaptation strategies, that allows to keep or improve plant growth regulation, should be studied under these environmental conditions [10,20]. Sunscreen materials that form an inert particle film upon the leaves, such as calcium carbonate, kaolin, and potassium silicate have been studied to increase reflective capacity, allowing leaf cooling, and reducing leaf and cluster sunburns under severe summer stress [24][25][26][27][28]. Shading nets produce a similar effect, and they are proposed as adaptation technique to mitigate the impacts of global warming in viticulture since limit the effects of high temperatures and to limit evapotranspiration [9].…”