The rootstock imparts different drought tolerance strategies in long-term field-grown deficit irrigated grapevines

Romero, P. and Acosta, J.M.N. and Pérez-Pérez, J.G. and Dodd, I.C. and Antolinos, V. and Marín, J.L. and Saavedra, F.D.A. and Molina, E.M. and Ordaz, P.B. (2025) The rootstock imparts different drought tolerance strategies in long-term field-grown deficit irrigated grapevines. Scientia Horticulturae, 346: 114167. ISSN 0304-4238

Abstract

Deficit irrigation was applied to Monastrell grapevines grafted on five different rootstocks (140Ru, 1103P, 41B, 110R and 161-49C) in south-eastern Spain for six years (2012–2017). The rootstocks modified fine root growth and soil respiration in the rhizosphere, soil-plant hydraulics, plant-water relations, leaf gas exchange, hormone signalling and primary and secondary metabolism. 161-49C vines showed a greater growth in fine root length density (RLD) in the rhizosphere (0–40 cm deep) and a higher root-to-shoot ratio compared with 140Ru or 110R. Both 161-49C and 1103P exhibited a tighter control of leaf water loss at low Ψs and high VPD. 161-49C vines had a lower root water uptake and water/nutrient transport capacity and, thus, were more water-stressed, water stress adaptation being related to higher hormone signalling aboveground (e.g., abscisic acid, ABA), greater activation of secondary metabolism in leaves and berries, and lower vine water use. In contrast, high-vigour/productive 140Ru had a lower RLD, but significantly higher soil respiration and [ABA]root.Vines grafted on 140Ru also showed greater root water uptake and increased whole-plant hydraulic conductance compared with the other rootstocks. This enhanced vine water status, leaf gas exchange, vegetative development, yield, and vine water use. The 140Ru rootstock conferred a greater leaf photosynthetic capacity, related to higher leaf N and chlorophyll contents, as well as a longer duration of leaf greenness. Thus, a rootstock conferring high vigor, such as 140Ru (and also 110R) with an effective root/water transport system, capable of maintaining high water uptake capacity and carbon gain would result in a more effective use of water under prolonged moderate/severe RDI. In contrast, 161-49C and 1103P were the most yield-sensitive and reactive rootstocks regarding water stress and high VPD, and are more suitable for less restrictive RDI strategies in these semiarid conditions.