Grapevine under deficit irrigation: hints from physiological and molecular data.

Stomata play a key role in plant adaptation to changing environmental conditions as they control both water losses and CO(2) uptake. Particularly, in the context of global change, simulations of the consequences of drought on crop plants are needed to design more efficient and water-saving cropping systems. However, most of the models of stomatal conductance (g(s)) developed at the leaf level link g(s) to environmental factors or net photosynthesis (A(net)), but do not include satisfactorily the effects of drought, impairing our capacity to simulate plant functioning in conditions of limited water supply. The objective of this review was to draw an up-to-date picture of the g(s) models, from the empirical to the process-based ones, along with their mechanistic or deterministic bases. It focuses on models capable to account for multiple environmental influences with emphasis on drought conditions. We examine how models that have been proposed for well-watered conditions can be combined with those specifically designed to deal with drought conditions. Ideas for future improvements of g(s) models are discussed: the issue of co-regulation of g(s) and A(net); the roles of CO(2), absissic acid and H(2)O(2); and finally, how to better address the new challenges arising from the issue of global change.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-3040.2010.02181.x

An overview of models of stomatal conductance at the leaf level

This review deals with grapevine responses to water stress by examining perturbations to physiological and molecular processes at the root, shoot, leaf and berry levels. Long-distance signalling among organs is also considered. Isohydric or anisohydric Vitis genotypes are described in relation to their response to drought, which is linked to stomatal behaviour. Stomatal regulation of grapevine under abscisic acid and hydraulic control (the latter being linked to embolism formation and recovery in water pathways upstream the stomata) is reviewed and linked to impairments of photosynthetic assimilation. We define three stages of photosynthesis regulation in grapevines that are subjected to progressive water stress on the basis of the main causes of assimilation decline. Early and late contributions of aquaporins, which play a fundamental role in water stress control, are discussed. Metabolic mechanisms of dehydration tolerance are rewieved, and variation linked to differences in transcript abundance of genes involved in osmoregulation, photosynthesis, photorespiration, detoxification of free radicals and coping with photoinhibition. Results of these defence strategies accumulated in berries are reviewed, together with perturbations of their molecular pathways. Features observed in different organs show that grapevine fits well as a complex model plant for molecular and physiological studies on plant drought avoidance/tolerance.

/pdf/drought-induced-changes-in-development-and-function-of-1x7v890ccr.pdf

Drought-induced changes in development and function of grapevine (Vitis spp.) organs and in their hydraulic and non-hydraulic interactions at the whole-plant level: a physiological and molecular update

The hybrid Richter-110 (Vitis berlandieri3Vitis rupestris) has the reputation of being a genotype strongly adapted to drought. A study was performed with plants of R-110 subjected to sustained water-withholding to induce acclimation to two different levels of water stress, followed by rewatering to induce recovery. The goal was to analyse how photosynthesis is regulated during acclimation to water stress and recovery. In particular, the regulation of stomatal conductance (gs), mesophyll conductance to CO2 (gm), leaf photochemistry (chlorophyll fluorescence and thermoluminescence), and biochemistry (Vc,max) were assessed. During water stress, gs declined to 0.1 and less than 0.05 mol CO2 m 22 s 21 in moderately and severely water-stressed plants, respectively, and was kept quite constant during an acclimation period of 1-week. Leaf photochemistry proved to be very resistant to the applied water-stress conditions. By contrast, gm and Vc,max were affected by water stress, but they were not kept constant during the acclimation period. gm was initially unaffected by water stress, and Vc,max even increased above control values. However, after several days of acclimation to water stress, both parameters declined below (gm )o r at (Vc,max) control values. For the latter two parameters there seemed to be an interaction between water stress and cumulative irradiance, since both recovered to control values after several cloudy days despite water stress. A photosynthesis limitation analysis revealed that diffusional limitations and not biochemical limitations accounted for the observed decline in photosynthesis during water stress and slow recovery after rewatering, both in moderately and severely stressed plants. However, the relative contribution of stomatal (SL) and mesophyll conductance (MCL) limitations changes during acclimation to water stress, from predominant SL early during water stress to similar SL and MCL after acclimation. Finally, photosynthesis recovery after rewatering was mostly limited by SL, since stomatal closure recovered much more slowly than gm.

http://max2.ese.u-psud.fr/publications/Flexas-Palma-JExpBot2009.pdf

Photosynthesis limitations during water stress acclimation and recovery in the drought-adapted Vitis hybrid Richter-110 (V. berlandieri×V. rupestris)

A PRI-based water stress index combining structural and chlorophyll effects: Assessment using diurnal narrow-band airborne imagery and the CWSI thermal index

A study was conducted to determine the relationship between midday measurements of vine water status and daily water use of grapevines measured with a weighing lysimeter. Water applications to the vines were terminated on August 24th for 9 days and again on September 14th for 22 days. Daily water use of the vines in the lysimeter (ETLYS) was approximately 40 L vine−1 (5.3 mm) prior to turning the pump off, and it decreased to 22.3 L vine−1 by September 2nd. Pre-dawn leaf water potential (ΨPD) and midday Ψl on August 24th were −0.075 and −0.76 MPa, respectively, with midday Ψl decreasing to −1.28 MPa on September 2nd. Leaf gs decreased from ~500 to ~200 mmol m−2 s−1 during the two dry-down periods. Midday measurements of gs and Ψl were significantly correlated with one another (r = 0.96) and both with ETLYS/ETo (r = ~0.9). The decreases in Ψl, gs, and ETLYS/ETo in this study were also a linear function of the decrease in volumetric soil water content. The results indicate that even modest water stress can greatly reduce grapevine water use and that short-term measures of vine water status taken at midday are a reflection of daily grapevine water use.

/pdf/midday-measurements-of-leaf-water-potential-and-stomatal-4l7gehw6g9.pdf

Midday measurements of leaf water potential and stomatal conductance are highly correlated with daily water use of Thompson Seedless grapevines

Water relations between leaf water potential, photosynthesis and agronomic vine response as a tool for establishing thresholds in irrigation scheduling

ADDITIONAL INDEX WORDS. Vitis vinifera, irrigation management, semiarid conditions, leaf water potential, stomatal conductance SUMMARY. Limited water supply in arid and semiarid Mediterranean environments demands improving irrigation efficiency. The purpose of this study was to determine a functional relationship between soil water availability and wine grape (Vitis vinifera) water status to determine a threshold value of soil matric potential to trigger irrigation. Seasonal trends of soil water potential, leaf water potential, and stomatal conductance (gS) of ‘Tempranillo’ wine grape were determined in two deficit irrigation treatments replenishing 45% and 30% of the reference evapotranspiration, and in a third non-irrigated treatment during 2001 and 2002. Soil water potential was measured with granular matrix soil moisture sensors placed at 0.3 m (Y0.3), 0.6 m (Y0.6), and 1.2 m (Y1.2) depths. The sensors at 0.3 m depth quickly responded to irrigation by increasing Y0.3 levels. At the 0.6 m depth, Y0.6 progressively decreased, showing significant differences between T1 and the rest of the treatments, while no significant differences in Y1.2 were found. All relationships between profile soil matric potential and leaf water potential and gS were highly correlated. After integrating our data with previous studies, we suggest a whole profile soil water potential value of ‐0.12 MPa as threshold to trigger irrigation and avoid severe water stress during berry growth.

/pdf/relationship-between-soil-and-plant-water-status-in-wine-4oa395bu2d.pdf

Relationship between Soil and Plant Water Status in Wine Grapes under Various Water Deficit Regimes

There are still some traditional vine-growing areas in Spain in which water-stressed vines are considered to produce berries with the highest quality must. To assess vine response to water availability, measured in terms of crop yield, vegetative development, and grape composition, five different irrigation treatments were evaluated over a five-year period in a Cabernet-Sauvignon vineyard in the Madrid region (Spain): no-irrigation (T0), water provided at 20 % of the reference evapotranspiration (ETo) (T20), water provided at 45 % of the ETo (T45), water provided at 20 % of the ETo until veraison and at 45 % thereafter (T20-45), and water provided at 45 % until veraison and 20 % thereafter (T45-20). A yield increment was observed with increasing water volumes. The T45 vines returned a consistent yield of around 8 t/ha, and a mean shoot weight of 30–50 g. The T0 and T20 plants showed reduced yields and vegetative growth in most years (yields being the most acutely affected). Berry weight was the yield component most influenced by water availability. In years of low rainfall, fertility was markedly reduced in the T0 vines. Providing a smaller irrigation volume before or after veraison (the T20-45 and T45-20 treatments) led to reductions in berry weight, cluster weight, and shoot weight over the last 3 years of the trial. Berry composition was almost unaffected by irrigation strategy. Taking into account yield, water use efficiency, and berry composition, the T45-20 treatment was the most efficient irrigation strategy.

https://link.springer.com/content/pdf/10.1007%2Fs00271-012-0348-y.pdf

Long-term effects of different irrigation strategies on yield components, vine vigour, and grape composition in cv. Cabernet-Sauvignon (Vitis vinifera L.)

This essay studies the morphological and anatomical properties of the leaves of Garnacha tinta, Tempranillo, Chardonnay and Airen grapevines in order to discover the drought adaptation strategies present in Vitis vinifera L The grapevines were grown under two water availability conditions: water limitation and non-water limitation There was a significantly lower development of leaf area under conditions of water limitation compared to non-water limitation due to a reduction in the size of main and lateral shoot leaves, and a smaller number of leaves on lateral shoots The development of the leaf area under water limitation conditions occurred on earlier dates than under non-water limitation conditions Significantly lower stomatal density was observed under water limitation conditions rather than non-water limitation conditions exclusively in the Airen cultivar

/pdf/drought-adaptation-strategies-of-four-grapevine-cultivars-18n79ojw2q.pdf

Pilar Baeza

Papers

Midday measurements of leaf water potential and stomatal conductance are highly correlated with daily water use of Thompson Seedless grapevines

Water relations between leaf water potential, photosynthesis and agronomic vine response as a tool for establishing thresholds in irrigation scheduling

Relationship between Soil and Plant Water Status in Wine Grapes under Various Water Deficit Regimes

Long-term effects of different irrigation strategies on yield components, vine vigour, and grape composition in cv. Cabernet-Sauvignon (Vitis vinifera L.)

Drought adaptation strategies of four grapevine cultivars ( Vitis vinifera L.): modification of the properties of the leaf area