Adaptive strategies of two Mediterranean grapevines varieties (Aragonez syn. Tempranillo and Trincadeira) face drought: physiological and structural responses

Abstract

At Mediterranean regions and particularly in southern Portugal, it is imperative to identify grape varieties more adapted to warm and dry climates in order to overcome future climatic changes. Two Vitis vinifera genotypes, Aragonez (syn. Tempranillo) and Trincadeira, were selected to assess their physiological responses to soil water stress. Vines were subjected to four irrigation regimes: irrigated during all phenological cycle, non-irrigated during all phenological cycle, non irrigated until veraison, irrigated after veraison. Predawn leaf water potential was much higher in Trincadeira than Aragonez in non-irrigated plants. This result is in accordance with its higher stomatal control efficiency in this variety (Trincadeira). Photosynthetic capacity (A max at saturating light intensity) decreased due to stomatal and biochemical limitations under water stress. However, recovery capacity of leaf water status after irrigation was faster in Trincadeira. Yield and yield x Brix increased when irrigation occurred after veraison, particularly in Trincadeira. These results show that Trincadeira presents a drought adaptation than Aragonez. Ratio of variable to maximum fluorescence F v /F m and total leaf chlorophyll related with leaf water potential for both species. Reflectance Normalized Difference Vegetation Index (NDVI 705 ), Red Edge Inflexion Point Index and Photochemical Reflectance Index were related with irrigation treatment. Relative water content and specific leaf area were similar between varieties. In conclusion, we suggested that there is variation among the genotypes and the main physiological parameters for variety selection, for drought, were leaf water potential, stomatal conductance and reflectance indexes.

Leaf morphoanatomy of four red grapevine cultivars grown under the same terroir

“…The differences observed between the four genotypes on stomata features (density, type and dimensions) might have been an adaptation to the environmental conditions namely for the tolerance to water stress [10,34]. In our study, stomata density varied significantly with genotype, with values of the same order of magnitude as those presented for the same grapevine red cultivars studied by Monteiro et al [26] at Torres Vedras WR (coastal area 60 km north from Lisbon) terroir but, with higher values than the ones observed by Costa et al [20] in Alentejo WR inland south Portugal), where Tr was considered more drought resistant [20,21]. The trichomes density and length varied with grapevine cultivars.…”

“…Despite being major cultivars, little is known about their tolerance to biotic and abiotic stresses. The cultivar TN is known as resistant to diseases and some pests but also as susceptible to water stress and excoriose; Tr is considered susceptible to downy and powdery mildew and Botrytis bunch rot and also as tolerant to drought stress [20,21,22]; CS is tolerant to diseases (powdery and downy mildews, Botrytis bunch rot) and to water stress but is susceptible to wooden diseases; Sy is susceptible to diseases (powdery and downy mildews, excoriose) and mites and tolerant to water stress (23).…”

Drought increases chlorophyll content in stems of Vitis interspecific hybrids

“…Drought affects leaf photosynthetic activity (Vaz et al 2016) by modifying the plant photosynthetic activity and inducing stomata closure with the consequent decrease in the ratio of CO 2 to O 2 . In extreme cases, intense water stress lead to leaf senescence and abscission, to reduce plant transpiration and water consumption (Munné-Bosch and Alegre 2004;Fini et al 2013;Herrera et al 2017).…”

Evaluating Strategies for Adaptation to Climate Change in Grapevine Production–A Systematic Review

“…Accordingly, plant materiel (cultivar and rootstock) should be selected for their drought tolerance. There are many studies comparing the behaviors of various grapevine genotypes under water-restricted conditions (e.g., Tomás et al, 2014 ; Vaz et al, 2016 ). Empirical knowledge of winegrowers is reported by Lereboullet et al ( 2013 ) in Australia: “ in 2011, many producers were starting to plant alternative Mediterranean varieties such as Grenache, Tempranillo or Mourvedre that offer a better resilience to water stress than Shiraz.” However, the understanding of the genetic factors relevant to water stress tolerance is still limited, and quantification of yield response to water scarcity for various cultivars and in interaction with other climate variables remains difficult.…”

“…Experimental approaches have been widely used to understand vines' responses to changes in climatic conditions. Controlled conditions allow for the study of processes when one or several environmental factors are changed: CO 2 enrichment (Bindi et al, 1996 ), experimental drought (Medrano et al, 2003 ; Şerdinescu et al, 2014 ; Vaz et al, 2016 ; Cirigliano et al, 2017 ; Chrysargyris et al, 2018 ), or elevated temperatures (Bonada et al, 2018 ). The conditions of experimentation largely differ: from greenhouse conditions with fruit-bearing cutting under totally controlled conditions (Torres et al, 2017 ), to less controlled field experiments.…”