Grapevine acclimation to water deficit: the adjustment of stomatal and hydraulic conductance differs from petiole embolism vulnerability

Abstract

Main conclusion Drought-acclimated vines maintained higher gas exchange compared to irrigated controls under water deficit; this effect is associated with modified leaf turgor but not with improved petiole vulnerability to cavitation. A key feature for the prosperity of plants under changing environments is the plasticity of their hydraulic system. In the present research we studied the hydraulic regulation in grapevines (Vitis vinifera L.) that were first acclimated for 39 days to well-watered (WW), sustained water deficit (SD), or transient—cycles of dehydration–rehydration—water deficit (TD) conditions, and then subjected to varying degrees of drought. Vine development under SD led to the smallest leaves and petioles, but the TD vines had the smallest mean xylem vessel and calculated specific conductivity (k ts). Unexpectedly, both the water deficit acclimation treatments resulted in vines more vulnerable to cavitation in comparison to WW, possibly as a result of developmental differences or cavitation fatigue. When exposed to drought, the SD vines maintained the highest stomatal (g s) and leaf conductance (k leaf) under low stem water potential (Ψs), despite their high xylem vulnerability and in agreement with their lower turgor loss point (ΨTLP). These findings suggest that the down-regulation of k leaf and g s is not associated with embolism, and the ability of drought-acclimated vines to maintain hydraulic conductance and gas exchange under stressed conditions is more likely associated with the leaf turgor and membrane permeability.Electronic supplementary materialThe online version of this article (doi:10.1007/s00425-017-2662-3) contains supplementary material, which is available to authorized users.

Review of water deficit mediated changes in vine and berry physiology; Consequences for the optimization of irrigation strategies

“…Similar results are reported by Munitz et al (2018) on a 4 year study with Cabernet-Sauvignon where high water availability during vegetative growth period increased vessel diameter and hydraulic conductivity and caused the vines to be more vulnerable to drought stress late in the season. This is confirmed by data of Hochberg et al (2017) who report that droughtacclimated vines maintained higher gas exchange compared to irrigated controls under water deficit. Vine water requirements can therefore increase in response to increased irrigation.…”

“…Morphological adaptations of upper ground tissue triggered by water deficit consist in adaptations that may participate in minimizing transpiration, including a reduction in leaf size and area (Gómez-del- Campo et al, 2002;Hochberg et al, 2017), and changes in thickness and composition of the waxy cuticle that would limit water loss through the leaf surface. The relation between cuticle components and their efficacy to limit water loss remains to be understood (Schreiber and Riederer, 2001).…”

Evolution of the Stomatal Regulation of Plant Water Content

“…New techniques that visualize the process of xylem cavitation clearly demonstrate that a similar role of stomatal closure in protecting the xylem from cavitation during water stress (Fig. 2) is also common to gymnosperms and angiosperms Hochberg et al, 2017). There are good examples of interaction between opening and closing signals to stomata during the early onset of plant desiccation, for example the opening of stomata at high vapor pressure deficit (VPD) by exposure to low CO 2 (Bunce, 2006).…”

“…There are good examples of interaction between opening and closing signals to stomata during the early onset of plant desiccation, for example the opening of stomata at high vapor pressure deficit (VPD) by exposure to low CO 2 (Bunce, 2006). However, the closure mechanism during drying appears to override all other signals as plants approach turgor loss (Aasamaa and Sõber, 2011;Bartlett et al, 2016), and subsequent xylem cavitation (Hochberg et al, 2017).…”

State-of-the-art of tools and methods to assess vine water status

“…Ѱ PD , and Ѱ stem are the most widely used water potentials in ecophysiological studies and industry (Dayer et al, 2017;Etchebarne et al, 2009;Ojeda, 2007;Ojeda et al, 2001Ojeda et al, , 2002Prieto et al, 2010;Sibille et al, 2007;Spangenberg and Zufferey, 2018;van Leeuwen et al, 2009;Zufferey et al, 2017Zufferey et al, , 2018, with Ѱ stem considered by some authors as showing the best correlations with vine transpiration (Choné et al, 2000(Choné et al, , 2001. However, this is challenged by others (Charrier et al, 2016;Hochberg et al, 2017;Santesteban et al, 2011).…”