Differential physiological response of the grapevine varieties Touriga Nacional and Trincadeira to combined heat, drought and light stresses

Abstract

Worldwide, extensive agricultural losses are attributed to drought, often in combination with heat in Mediterranean climate regions, where grapevine traditionally grows. The available scenarios for climate change suggest increases in aridity in these regions. Under natural conditions plants are affected by a combination of stresses, triggering synergistic or antagonistic physiological, metabolic or transcriptomic responses unique to the combination. However the study of such stresses in a controlled environment can elucidate important mechanisms by allowing the separation of the effects of individual stresses. To gather those effects, cuttings of two grapevine varieties, Touriga Nacional (TN) and Trincadeira (TR), were grown under controlled conditions and subjected to three abiotic stresses (drought - WS, heat - HS and high light - LS) individually and in combination two-by-two (WSHS, WSLS, HSLS) or all three (WSHSLS). Photosynthesis, water status, contents of H2 O2 , abscisic acid and metabolites of the ascorbate-glutathione cycle were measured in the leaves. Common and distinct response features were identified in the different stress combinations. Photosynthesis was not hindered in TN by LS, while even individual stresses severely affect photosynthesis in TR. Abscisic acid may be implicated in grapevine osmotic responses since it is correlated with tolerance parameters, especially in combined stresses involving drought. Overall, the responses to drought-including treatments were clearly distinct to those without drought. From the specific behaviours of the varieties, it can be concluded that TN shows a higher capacity for heat dissipation and for withstanding high light intensities, indicating better adjustment to warm conditions, provided that water supply is plentiful.

Impacts of warming and water deficit on antioxidant responses in Panicum maximum Jacq

“…According to Czarnocka and Karpiński (), plants subjected to abiotic stress form the triplet chlorophyll ( 3 Cl • ), which transmits excess energy to O 2 thereby forming ROS; however, this excess energy can be captured by carotenoids to avoid ROS formation. This behaviour of carotenoids, as a protective agent against water deficit, is reported by Mibei et al (), whereas Carvalho et al () observe an increase in carotenoid content in Vitis vinifera subjected to combined stresses (water stress + temperature increase).…”

Cutting the Gordian Knot of abiotic stress in grapevine: From the test tube to climate change adaptation

“…As the most common abiotic stresses affecting grapevine in the Mediterranean summer are drought, heat and excess light, the effects of those stresses individually and in all the combinations between them were analyzed in leaves of ‘Touriga Nacional’ and ‘Trincadeira’, two widely used Portuguese wine‐growing varieties, with distinct physiological behaviors in the field (Carvalho et al ). The plants were evaluated for photosynthetic performance through several physiological parameters (Table ).…”

“…The plants were evaluated for photosynthetic performance through several physiological parameters (Table ). The main aim was to understand the response mechanisms and the antagonistic or synergistic effects that the combination of abiotic stresses can induce, and thus change the prior perceptions of ‘tolerance’ or ‘sensitivity’ of each variety (Carvalho et al ). Common and distinct stress‐response features, namely regarding drought, were identified.…”

Melatonin enhances thermotolerance by promoting cellular protein protection in tomato plants

“…Exogenous application of JA as well as its enhancement of endogenous levels by the overexpression of JA biosynthetic gene confers thermotolerance in Arabidopsis thaliana . Moreover, biosynthesis of plant metabolites, such as soluble sugars, amino acids, organic acids, and lipids, is also affected by high temperature; nevertheless, they are also crucial for plant adaptation to high‐temperature stress …”