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The productivity of Vitis vinifera L. is limited by salinity, especially under water and drainage deficits, and could aggravate with climate change. The use of tolerant rootstocks is a strategy against salinity that helps yield maintenance. Some Argentinean grapevine cultivars show tolerance to salinity, although the mechanisms are yet unknown. The physiology of Malbec vines was evaluated with 4 V. vinifera rootstocks: Torrontés Riojano (TR) and Torrontés Sanjuanino (TS) Argentine varieties, and the hybrids 3309 Courdec (3309C, salinity sensitive) and 1103 Paulsen (1103P, tolerant), submitted to NaCl 0, 50 or 100 mM during 65 days. Mild and high salinity levels reduced vegetative growth (50 and 70%, respectively), photosynthesis and leaf water content. Midday ΨL reached − 1.16 MPa (moderate water stress) with 100 mM NaCl, which expressed as oxidative damage in mature leaves, thus affecting protein content, membrane integrity and lipid peroxidation. Proline accumulation in leaves increased in 1103P and TR under 50 mM, while 1103P showed the highest value in 100 mM NaCl. An increased vegetative expression and vigor were induced by TS. Accumulation of Na+ and Cl− ions in roots was found in TR and TS, suggesting a compartmentalization strategy, while 1103P excluded them. [ABSTRACT FROM AUTHOR]

Plants have evolved an array of specific photoreceptors to acclimate to the light environment. By sensing light signals, photoreceptors modulate plant morphology, carbon- and water-physiology, crop yield and quality of harvestable organs, among other responses. Many cultural practices and crop management decisions alter light quantity and quality perceived by plants cultivated in the field. Under full sunlight, phytochromes perceive high red to far red ratios (R:FR; 1.1), whereas overhead or lateral low R:FR (below 1.1) are sensed in the presence of plant shade or neighboring plants, respectively. Grapevine is one of the most important fruit crops in the world. To date, studies on grapevine response to light focused on different Photosynthetic Active Radiation (PAR) levels; however, limited data exist about its response to light quality. In this study we aimed to investigate morphological, biochemical, and hydraulic responses of Vitis vinifera to variations in R:FR. Therefore, we irradiated Syrah and Torrontés Riojano plants, grown in a glasshouse, with lateral FR light (low lateral R:FR treatment), while others, that were kept as controls, were not irradiated (ambient lateral R:FR treatment). In response to the low lateral R:FR treatment, grapevine plants did not display any of the SAS morphological markers (i.e. stem length, petiole length and angle, number of lateral shoots) in any of the cultivars assessed, despite an increase in gibberelins and auxin concentrations in leaf tissues. Low lateral R:FR did not affect dry matter partitioning, water-related traits (stomata density and index, wood anatomy), or water-related physiology (plant conductance, transpiration rate, stem hydraulic conductivity, stomatal conductance). None of the Vitis vinifera varieties assessed displayed the classical morphological and hydraulic responses associated to SAS induced by phytochromes. We discuss these results in the context of natural grapevine environment and agronomical relevance. [ABSTRACT FROM AUTHOR]