The hybrid Richter-110 (Vitis berlandieri x Vitis rupestris) (R-110) has the reputation of being a genotype strongly adapted to drought. A study was performed with plants of R-110 subjected to water withholding followed by re-watering. The goal was to analyze how stomatal conductance (g(s)) is regulated with respect to different physiological variables under water stress and recovery, as well as how water stress affects adjustments of water use efficiency (WUE) at the leaf level. Water stress induced a substantial stomatal closure and an increase in WUE, which persisted many days after re-watering. The g(s) during water stress was mainly related to the content of ABA in the xylem and partly related to plant hydraulic conductivity but not to leaf water potential. By contrast, low g(s) during re-watering did not correlate with ABA contents and was only related to a sustained decreased hydraulic conductivity. In addition to a complex physiological regulation of stomatal closure, g(s) and rate of transpiration (E) were strongly affected by leaf-to-air vapor pressure deficit (VPD) in a way dependent of the treatment. Interestingly, E increased with increasing VPD in control plants, but decreased with increasing VPD in severely stressed plants. All together, the fine stomatal regulation in R-110 resulted in very high WUE at the leaf level. This genotype is revealed to be very interesting for further studies on the physiological mechanisms leading to regulation of stomatal responsiveness and WUE in response to drought.

Background and Aims:  A 3‐year study was carried out in order to evaluate the ecophysiology, yield and quality characteristics of Vitis vinifera L. cv. Kékfrankos (syn. Limberger) at Eger‐Nagyeged hill (steep slope) and at Eger‐Kőlyuktető (flat) vineyard sites located in the Eger wine region, Hungary. The aim of this paper was to analyse the effect of ‘vintage’ and ‘terroir’ on the seasonal changes of Kékfrankos ecophysiology and its possible relationship with yield and wine composition. Methods and Results:  Grapevine physiological responses (midday‐ and pre‐dawn water potential, pressure–volume analysis and gas‐exchange), growing stages, yield and wine composition of each vineyard were studied. Lower grapevine water supply was detected at Eger‐Nagyeged hill in each season due to its steep slope and soil characteristics. Pressure‐volume curves indicated that there was no osmotic adjustment in the leaves of this variety. Higher osmotic concentration was measured at turgor loss and full turgor in the leaves of the unstressed vineyard (Eger‐Kőlyuktető) presumably due to higher photosynthetic activity. Differences in soil water content of the vineyards resulted in a slightly altered cell wall elasticity. Stomatal conductance, transpiration rate and photosynthetic production per unit leaf area were affected by water availability. Lower yield in Eger‐Nagyeged hill was partly associated with decreased photosynthetic production of the canopy. Improved wine quality of Eger‐Nagyeged hill was due to moderate water stress which induced higher concentration of anthocyanins and phenolics in the berries. The duration of the phenological stages was dependent on vintage temperature characteristics rather than on vineyard site. Conclusion:  There was a close relationship between environmental conditions, Kékfrankos gas‐exchange, water relations, yield and wine composition. Water deficit plays an important role in creating a terroir effect, resulting in decreased yield, better sun exposure of leaves and clusters and thus higher concentration of phenolics and anthocyanins. Although quality is mainly influenced by vintage differences, vineyard characteristics are able to buffer unfavourable vintage effects even within a small wine region. Significance of the Study:  Stomatal conductance, pre‐dawn water potential and climatic data may be reliable parameters for terroir classification, although variety–terroir interactions must always be considered.

No abstract

No abstract

68Several technological applications can be used in order to reduce these negative effects. 69Cluster thinning (Guidoni et al., 2002; Prajitna et al., 2007), girdling (Singh Brar et al., 2008; 70 Koshita et al., 2011) and early defoliation (Poni et al., 2006; Poni et al., 2009; Kemp et al., 2011; variety, fungal infections and yield (Jeandet et al., 1995; Bavaresco 2003; Bavaresco et al., 2007; 75 Prajitna et al., 2007). There are also some paper which are dealing with increasing resveratrol 76 concentration in grapes using elicitors (Vezzulli et al., 2007; Santamaria et al., 2011). accumulation is very fast at the Nagy-Eged-hill, leading too alcoholic, unbalanced wines. 91Besides, the desired level of phenolic maturity cannot be achieved in most of the vintages. The Three one kg samples for each treatment were collected at random from several clusters before 121 vinification. The berries were selected randomly from the upper, middle, and lower parts of the 122 bunches. All the berry samples were prepared and analyzed within 2 hours after the harvest. juices was determined at 20 °C using a hand-held refractometer (Atago MASTER-α, Japan). 137 Assesment of grape phenolic maturity 138The phenolic potential of grapes was calculated according to the method described by with their pedicel were removed from the bunch, they were laid on the plate of the analyzer and 158 then they were punctured in the lateral face (Letaief et al., 2008a). The skin break force (F sk ), 159 skin break energy (W sk ) and Young's modulus of berry skin (E sk ) were calculated from the 160 puncture test data using the software Exponent 6.1.4.0. Berry skin thickness (Sp sk ) was measured 161 using a P/2 probe with 2 mm diameter. For this measurement, approximately 0.25 cm 2 skin was 162 removed from the lateral face of the berry. The skin was carefully and gently cleaned of pulp, and 163 then placed on the platform and the test was conducted as described by other authors previously 164( Letaief et al., 2008a; Letaief et al., 2008b; Río Segade et al., 2008