In viticulture, bunch rot is considered a major issue due to the elevated intrinsic varietal susceptibility, leading to significant yield and quality losses. Pinot blanc can be severely affected by late-season bunch rot, primarily due to its characteristically compact bunch structure. While several vineyard management practices can induce looser bunch architecture, clonal selection offers the potential to identify individuals with naturally less compact bunches without major penalties on yield or juice chemical parameters. In this study, six Pinot blanc clones (namely, ersa140, 141, and 142; Lb16 and 18; and SMA102), trained to “pergola semplice”, were evaluated over five years in an experimental vineyard in the Trentino region. The evaluation focused on traits associated with yield and its components, bunch compactness, juice chemical parameters, and bunch rot incidence. The results revealed contrasting traits among clones, with a gradient in yield and related components across the tested material. Although differences in bunch compactness were observed—expressed as the ratio between bunch weight and rachis length (ranging from 6 to 15 g/cm)—the loose bunch trait was primarily associated with reduced yield and was linearly related to an increased number of stenospermocarpic berries. Clones with looser bunches exhibited higher °Brix and pH levels, likely due to berry dehydration (potentially driven by accelerated ripening following an unbalanced leaf-to-fruit ratio) and increased potassium uptake, respectively. Bunch rot frequency and the number of bunches exhibiting high rot incidence varied among clones, potentially due to two non-mutually exclusive mechanisms: (i) looser bunch architecture and (ii) specific properties of the berry skin. This study provides evidence of a strong relationship between bunch characteristics and yield potential in the six Pinot blanc clones evaluated, which should be considered in future vineyard planning. Intermediate clones, such as Lb18 and especially SMA102, were characterised by moderate vine productivity levels (~3 kg per vine) combined with good tolerance to bunch rot, suggesting their suitability for environments with moderate disease pressure without incurring severe yield penalties.

Canopy management in viticulture involves key agronomic practices aimed at balancing the leaf-to-fruit ratio and optimizing microclimates for leaves and bunches. In temperate-to-cool regions, intensive green pruning is essential for effective crop protection and aroma development. However, rising temperatures and stress conditions are prompting a re-evaluation of these practices to mitigate negative impacts from overexposed bunch-zones such as sugar accumulation, acidity loss, sunburn, anthocyanin degradation, and reduced vine longevity. This study explored alternative, more conservative green pruning methods in Guyot-trained Cabernet Franc and Nermantis (a pathogen-resistant hybrid) over two years to: i) reshape berry and leaf microclimate, ii) evaluate berry quality, and iii) assess wine aroma and sensory characteristics. Significant differences emerged between minimal and intensive canopy management strategies. Reduced intervention led to: 1) lower canopy porosity and bunch light exposure; 2) reduced leaf photoinhibition; 3) cooler berry temperatures; 4) better sugar-acid balance at harvest; and 5) higher anthocyanin levels. These effects held across contrasting seasons—2022 (hot, dry) and 2023 (cool, wet)—though driven by different putative mechanisms: differences in berry microclimate in 2022 and unbalanced leaf-to-fruit ratio in 2023. While wine chemistry showed little variation, aroma profiles were clearly affected. However, sensory analysis revealed varietal sensitivity, with Cabernet Franc more responsive than Nermantis, especially for aroma. Assuming summer pruning as a critical operation in the context of grapevine crop protection, the possibility to exploit the potential inherently higher tolerance to fungal pathogens of hybrid varieties is discussed.

Olive (Olea europaea L.) is an important Mediterranean tree species with a longstanding history of cultivation, boasting a diverse array of local cultivars. While traditional olive orchards are valued for their cultural and aesthetic significance, they often face economic sustainability challenges in the modern context. The success of both traditional and newly introduced cultivars (e.g. those obtained by cross-breeding) is hindered by self-incompatibility, a prevalent issue for this species that results in low fruit set when limited genetic diversity is present. Further, biological, environmental, and agronomic factors have been shown to interlink in shaping fertilization patterns, hence impacting on the final yield. Climatic conditions during pollination, such as excessive rainfall or high temperatures, can further exacerbate the problem. In this work, we provide an overview of the various factors that trigger the phenomenon of suboptimal fruit set in olive trees. This work provides a comprehensive understanding of the interplay among these factors, shedding light on potential mechanisms and pathways that contribute to the observed outcomes in the context of self-incompatibility in olive.

The wine sector, among the most profitable agricultural segments, has been markedly affected by the ongoing climate change impacts, such as warmer climate conditions with higher frequency of extreme temperatures and a trend of decreasing precipitation. All this results in higher evaporative demand and therefore higher occurrence of water stress events leading to advancement of temperature-sensitive phenological stages (e.g., budburst and ripening). Such negative effects eventually affect berry development and quality, especially in historically valuable viticultural areas, forcing winegrowers to work within a compressed harvest period to maintain wine typicity. In this work we examined the relationship between environmental variables (air and soil temperature, relative humidity, precipitation, and solar radiation), phenology, berry, and wine quality for the two varieties (Chardonnay and Teroldego) in Trentino Alto-Adige/South Tyrol (Italy) over 36 years. Huglin Index (a bioclimatic heat index), growing degree days (measure of heat accumulation), and overall mean temperature showed linear increase (p < 0.001) in the last years, while no variations were recorded for precipitations. Despite no major effects being observed for phenological interval lengths, the onset of most of the phenological stages for both varieties had significantly (p < 0.001) advanced. However, i) early budburst pushed the budburst-flowering interphase by -1.2 days every two years toward putative colder periods with increased late frost probability and potential slower phenological progression towards flowering, and ii) early veraison shifted the veraison-ripening interphase by 0.25 day per year into warmer periods that oppositely impose faster phenological advancement. Hence, a substantial equilibrium in the seasonal growing length over years was maintained. Potential carry-over effects from the previous season were observed, particularly associated with heat requirements to unlock early phenological events, raising additional concerns on the additive effects of climate change to viticulture. Generally, white wine quality increased (p < 0.05) over the years, while red and sparkling wines remained unaffected. This was putatively related to accurate harvest date decision-making dictated by berry quality parameters: sugar-to-acidity ratio for Chardonnay and bunch sanitary status for Teroldego. Overall, this work provides evidence of the dynamics involved in climate change, and, to our knowledge, its overlooked effects on viticulture, thus providing new insights that can contribute to further developing adaptive strategies.

Deciphering grapevine dormancy is crucial in the current context of climatic challenges: advancing budburst phenology and increased late frost probabilities, observed in the last decades and expected to further increase, require deeper understanding. Beyond higher mean temperatures, abiotic stresses such as water deficit have also been emphasized as actors. In this framework, we aimed at exploring new methodologies for tracking dormancy cycle and testing the interplay on its regulation of temperature dynamics and drought.In a first experiment, twenty-one Vitis vinifera varieties were monitored during ecodormancy and budburst over three years. The dataset, consisting of BBCH scale values, growing degree days (GDD) accumulation, and quantum yield of dark-adapted photosystem II (Fv/Fm) of bud sections, allowed us to identify non-linear associations of Fv/Fm ratio with early phenology and GDD6. Therefore, we propose it as a quantitative and reliable tool for further analyses.In a second experiment, Chardonnay plants underwent water deficit stress or full-field capacity irrigation throughout the season. In addition to the methods described above, by sampling nodes at different timepoints during dormancy and exposing them to budbreak-forcing conditions, we tracked dormancy phases and their relationship with water deficit stress, acclimation and deacclimation dynamics. Annual climate and dormancy cycle exhibit profound interdependence: oscillating temperature trends and stresses combinations lead grapevines to a plastic and varietal-specific response, possibly influenced by these same factors in several previous years. The above findings and their underlying physiological mechanisms will be presented and discussed.

Early budburst is becoming an increasingly challenging topic in viticulture. Anticipating vegetative resume results in an overall phenological advance, in potential higher risks of late frost and subsequent negative effects on berry quality and overall vine productivity. Phenotypic variation for date of budburst onset (BBCH07) is known in Vitis vinifera and potential exploitation of data regarding thermal requests to reach BBCH07 are critical in defining new avenues for viticulture. Nevertheless, reproducible methods are lacking in defining phenological progression in grapevine and further efforts are needed to standardize quantitative dataset associated with early growth stages appearance. In this work, a panel of twenty-one Vitis vinifera varieties grown in an experimental vineyard were assessed for early phenological onset (pre-to-post budburst) via visual observation, quantum yield of photosystem II in the dark adapted (Fv/Fm) bud section and growing degree days accumulation over three years. Further experiments were carried out under controlled environmental conditions to evaluate the effect of different simulated late frost on bud viability. Our data proposes Fv/Fm from bud section as a quantitative and reliable tool, although destructive following our pipeline, to monitor early phenological events in grapevine with significant non-linear associations of the Fv/Fm with growing degree days on base 6 °C (GDD6) and phenology. We observed significant (p < 0.001) inter-varietal variation for thermal requests to reach budburst ranking from 140 to 260 GDD6 although some varieties showed inconsistent data between years (i.e. a plastic response). Late frost damage was associated with phenological progression suggesting a linear and positive correlation between cold injury and de-acclimation from cold hardiness up until first leaf appearance. However, monitoring Fv/Fm in selected varieties provided evidence of varietal-specific response to late frost with e.g., Chardonnay and Gewürztraminer showing maintenance of photosystem II activity even at advanced phenological stages. This suggests the presence of preferable acclimation mechanisms to late frost in Vitis vinifera that will deserve further investigation. Our data provides a comprehensive analysis of early phenological events in grapevine, providing novel methods of assessment (Fv/Fm), varieties possessing escape strategies (i.e. large thermal accumulation to reach BBCH07) and varieties with putative late frost tolerance even after budburst. Overall, further work is ongoing to define the mechanisms underlying late frost tolerance per se and to identify novel varieties with preferable combination of traits.

In a scenario of changing climate conditions, grapevine is significantly affected at multiple levels. Advancements in phenology and berry ripening, however, are the major dynamics of the generalized increase in average temperature and evaporative demand, negatively affecting berry quality and productivity. The aim of this work was to unravel the underlying mechanisms of bunch-zone auxin application (NAA; 1-Naphthaleneacetic acid) and source-limiting canopy management approaches in delaying berry ripening. In randomized block design experiments, control vines were compared to vines treated with NAA, subjected to apical-to-bunch defoliation or antitranspirant application (n=10-to-42 plants per treatment). Juice chemical analysis, berry ripening kinetics and physiological traits were monitored every week from pre-veraison over multiple vineyards, years (2021, 2022, 2023) and varieties (Chardonnay, Pinot gris, Syrah, Merlot). Overall, all the treatments delayed berry ripening, and in particular °Brix build up, by 7 to up 15 days. Opposite trends were observed for total acidity, particularly malic acid concentration that displayed a slower degradation kinetic post-veraison. Time course expression profile of ripening-associated transcription factors revealed a significant and consistent repression for VviNAC60, VviNAC33, VviBHLH75, VviWRKY19, VviERF45 following the application of delaying ripening techniques. Similarly, abscisic acid and Indole-3-acetic acid concentration in the berry were modulated by treatments, with specific variation for their free and conjugated forms. This work enlightens, for the first time, the mechanistic framework of berry ripening dynamics following specific treatments with different mechanisms of action and provides novel avenues to harmonize management approaches in grapevine in the context of climate change.

Transpiration per unit of leaf area is the end-product of the root-to-leaf water transport within the plant, and it is regulated by a series of morpho-physiological resistances and hierarchical signals. The rate of water transpired sustains a series of processes such as nutrient absorption and leaf evaporative cooling, with stomata being the end-valves that maintain the optimal water loss under specific degrees of evaporative demand and soil moisture conditions. Previous work provided evidence of a partial modulation of water flux following nitrogen availability linking high nitrate availability with tight stomatal control of transpiration in several species. In this work, we tested the hypothesis that stomatal control of transpiration, among others signals, is partially modulated by soil nitrate ( NO 3 - ) availability in grapevine, with reduced NO 3 - availability (alkaline soil pH, reduced fertilization, and distancing NO 3 - source) associated with decreased water-use efficiency and higher transpiration. We observed a general trend when NO 3 - was limiting with plants increasing either stomatal conductance or root-shoot ratio in four independent experiments with strong associations between leaf water status, stomatal behavior, root aquaporins expression, and xylem sap pH. Carbon and oxygen isotopic signatures confirm the proximal measurements, suggesting the robustness of the signal that persists over weeks and under different gradients of NO 3 - availability and leaf nitrogen content. Nighttime stomatal conductance was unaffected by NO 3 - manipulation treatments, while application of high vapor pressure deficit conditions nullifies the differences between treatments. Genotypic variation for transpiration increase under limited NO 3 - availability was observed between rootstocks indicating that breeding (e.g., for high soil pH tolerance) unintentionally selected for enhanced mass flow nutrient acquisition under restrictive or nutrient-buffered conditions. We provide evidence of a series of specific traits modulated by NO 3 - availability and suggest that NO 3 - fertilization is a potential candidate for optimizing grapevine water-use efficiency and root exploration under the climate-change scenario.

Grapevine is one of the most important crops cultivated across Europe. Climate factors and diseases constantly threaten its production. Recently, Flavescence dorée (FD), an incurable grapevine disease with the obligation to uproot each infected plant, has been widely spread in Europe. The symptoms of FD are visually expressed in the late summer. Currently, the adopted procedure consists in scouting for infected plants by trained experts, which is time-consuming and not frequent enough. As stress development causes subtle spectral changes before any visible symptoms appear, during the summer of 2022, hyperspectral and multispectral images were acquired in the two vineyards near Riva del Garda, Trentino, Italy. A classification accuracy between 90.2 % and 96.9 % in distinguishing between infected and healthy plants was obtained from the hyperspectral data. These findings justify further efforts to use an in-house developed, affordable multispectral camera, significantly reducing equipment cost and procedure complexity while mapping the relevant spectral channels.

Targeted pruning techniques may have the potential to shift phenological progression in grapevines. These approaches can be useful to escape late frost (after budburst) and to delay ripening, maintaining yield and berry quality under specific environmental scenarios and for targeted oenological aims. In this work we tested a series of pruning methods (late pruning and different forcing approaches to unlock the para-dormant buds) with the primary objective of delaying phenological onset while increasing must quality components in the Trento DOC basin (Italy) over three field seasons either in cv Chardonnay or cv Pinot noir. Delayed pruning shifted the onset of most of the phenological stages by 3 to 10 days with a general increase in must acidity at harvest over two seasons. Forcing techniques, and in particular forcing vine regrowth (i.e., removing primary productivity along with leaves and secondary shoots to force dormant bud growth), substantially reduced yield per vine (p < 0.001) but significantly (p < 0.001) enhanced total acidity and yeast available nitrogen when compared to winter pruning vines in both Chardonnay and Pinot noir. Different spring pruning for unlocking para-dormant buds aimed at double-cropping in 2022 did not yield a secondary harvest potentially due to lack of vigor in the vineyard (Pinot noir) and unfavorable environmental conditions that putatively anticipated bud pre-dormancy. However, reduced sugar levels in the primary productivity bunches of the treated vines were observed, suggesting that early source limitation (e.g., at fruit set) applied via reduced active photosynthetic leaf area may slow down technological ripening even if compensatory behaviors were observed in the treated plants through enhanced stomatal conductance. Our work provides evidence of the potential usefulness of different pruning approaches for manipulating phenological progression and berry ripening dynamics under climate change scenario in the Trento DOC area and suggests a lack of efficacy and specific drawbacks particularly in dry and hot years.

Agriculture is under constant pressure to increase the production rate and to provide more food or resources for other industries. Without precision agriculture it is not possible to fulfil these requirements. Medium and large-size farms already adopted this technology, but small farms are far from precision agriculture due to the high initial costs. In this paper we present a bespoke and affordable multispectral camera for precision farming and illustrate its application in the detection of Flavescence dorée. This is a grapevine disease that makes a great concern to grapevine producers in the whole Mediterranean region. Flavescence dorée is the only quarantine disease in the European region. The related mandatory control procedures include uprooting every infected plant, with the obligation to uproot the vineyard when the infection exceed the 20% of threshold infection, hence resulting in a high economical loss. Thus, it is highly important to detect even a single infected plant over an entire vineyard plot, preventing the spreading of Flavescence dorée at earliest stages. We used the in-house developed multispectral camera together with a hyperspectral camera to acquire data from two vineyards near Riva del Garda, Trentino, Italy, during the summer of 2022. These data are the starting point for selecting the optimal spectral bands for the detection of Flavescence dorée using affordable multispectral approaches and developing an appropriate classification algorithm.

Stomata control CO2 uptake for photosynthesis and water loss through transpiration, thus playing a key role in leaf thermoregulation, water-use efficiency (iWUE), and plant productivity. In this work, we investigated the relationship between several leaf traits and hypothesized that stomatal behavior to fast (i.e. minutes) environmental changes co-determines, along with steady-state traits, the physiological response of grapevine to the surrounding fluctuating environment over the growing season. No relationship between iWUE, heat stress tolerance, and stomatal traits was observed in field-grown grapevine, suggesting that other physiological mechanisms are involved in determining leaf evaporative cooling capacity and the seasonal ratio of CO2 uptake (A) to stomatal conductance (gs). Indeed, cultivars that in the field had an unexpected combination of high iWUE but low sensitivity to thermal stress displayed a quick stomatal closure to light, but a sluggish closure to increased vapor pressure deficit (VPD) levels. This strategy, aiming both at conserving water under a high to low light transition and in prioritizing evaporative cooling under a low to high VPD transition, was mainly observed in the cultivars Regina and Syrah. Moreover, cultivars with different known responses to soil moisture deficit or high air VPD (isohydric versus anisohydric) had opposite behavior under fluctuating environments, with the isohydric cultivar showing slow stomatal closure to reduced light intensity but quick temporal responses to VPD manipulation. We propose that stomatal behavior to fast environmental fluctuations can play a critical role in leaf thermoregulation and water conservation under natural field conditions in grapevine.

Compact bunches have been often associated with higher susceptibility to Botrytis cinerea and therefore reduction in berry quality in grapevine. The objective of this study was to evaluate three management methods (early leaf removal, gibberellic acid, and their combination) for reducing bunch compactness in Vitis vinifera cv. Pinot gris trained in two different training systems with contrasting vigor (Guyot and pergola). Treatments were applied at BBCH 62 or BBCH 65 and yield components, total soluble solids, fruit set, and bunch compactness parameters were evaluated. Both treatments individually reduced berry number, mean bunches weight and bunches compactness as well as yield per vine when compared to control-untreated vines. However, no major differences were observed when both the treatments were applied in combination for Guyot or pergola although a higher reduction in yield was detected for Guyot and a significant increase in total soluble solids was observed in pergola. Our study suggests that intense leaf removal and gibberellic acid applied at early flowering can help reducing bunch compactness in Pinot gris and showing it in two training systems. In particular, leaf removal represents a valuable alternative to plant growth regulators (i.e., gibberellic acid) as applicable in organic viticulture.

Shoot topping and other summer grapevine management practices are considered crucial for producing high-quality wine. However, in recent years, climate change is increasing the need to reassess these strategies, as excessive radiation and high temperatures can negatively impact canopy functionality and berry quality. Indeed, it has been hypothesized that limiting summer vegetative pruning may protect the bunch, via shading, and the leaf by maintaining a more favorable environment for leaf functionality (e.g., lower VPD, reduced high light stress) owing to a denser canopy. In this work, a series of canopy manipulation treatments (shoot topping vs. long-shoot bundling; secondary shoot trimming vs. untrimmed) were tested in a replicated factorial block design over two seasons in field-grown grapevine plants (cv. Cabernet Franc grafted in SO4). Overall, treatments in which secondary shoot removal and/or shoot topping were not applied produced a higher canopy area, increased pruning wood and leaf layers, and had a higher Fv/Fm on warm days when compared to pruned canopies. These were associated with a year-dependent modulation of quality parameters of the must in which long-shoot bundling treatment, overall, produced the highest polyphenol and anthocyanin contents and must acidity. Our data provide evidence of a potential usefulness of preserving dense canopies under high temperature – high irradiance conditions with desirable effects on leaf photosynthesis and must quality when long-shoot bundling was applied.

The vegetative-reproductive balance is critical in determining grapevine quality and productivity. Many agri-cultural practices (bunch thinning, defoliation, green pruning) can modify the source-sink relationships leading to altered vineyard efficiency and berry quality. Field experiments aimed at understanding how a decrease in sink availability influences leaf physiology of the reproductive shoot. In Pinot noir trained to guyot, control shoots were compared to shoots subjected to basal girdling (G), bunch removal (BR) or a combination of both treatments (G + BR). Morpho-physiological traits including leaf water status, gas-exchange, leaf temperature, chlorophyll fluorescence, leaf starch and soluble sugars, petiole and leaf dry weight were collected at different time of the day and over several days to evaluate the dynamics of leaf functionality following treatments application. The gradual reduction in sink availability induced significant reductions in leaf gas-exchange and PSII efficiency from the second day after the treatments' application. Nonetheless, while reductions in photo-synthetic capacity and increases in leaf temperature associated with a compromised stomatal physiology were present in the G + BR shoots, no differences were observed between bunch removal and control treatments. Girdling and G + BR showed a significant reduction in leaf chlorophyll a and b as well as carotenoids content when compared to control shoots. The increase in the source-sink ratio subsequently produced a marked increase in leaf starch, hexoses and sucrose accompanied by a reduction in the specific leaf area while the girdling did not affect the weight and brix degree of the bunches. This work shows how the progressive reduction in sink availability compromises leaf physiological functionality putatively owing to a reduction in assimilates trans -location capacity from the leaf and hence starch storage and accumulation. However, limited effects were observed for shoots in which only the bunch was removed suggesting that assimilates allocation to other vegetative and/or reproductive sinks can maintain leaf functionality even in days characterized by unfavorable environmental conditions.

Rising temperature is among the most remarkably stressful phenomena induced by global climate changes with negative impacts on crop productivity and quality. It has been previously shown that volatiles belonging to the isoprenoid family can confer protection against abiotic stresses. In this work, two Vitis vinifera cv. ‘Chardonnay’ clones (SMA130 and INRA809) differing due to a mutation (S272P) of the DXS gene encoding for 1-deoxy-D-xylulose-5-phosphate (the first dedicated enzyme of the 2C-methyl-D-erythritol-4-phosphate (MEP) pathway) and involved in the regulation of isoprenoids biosynthesis were investigated in field trials and laboratory experiments. Leaf monoterpene emission, chlorophyll fluorescence and gas-exchange measurements were assessed over three seasons at different phenological stages and either carried out in in vivo or controlled conditions under contrasting temperatures. A significant (p < 0.001) increase in leaf monoterpene emission was observed in INRA809 when plants were experiencing high temperatures and over two experiments, while no differences were recorded for SMA130. Significant variation was observed for the rate of leaf CO2 assimilation under heat stress, with INRA809 maintaining higher photosynthetic rates and stomatal conductance values than SMA130 (p = 0.003) when leaf temperature increased above 30 °C. At the same time, the maximum photochemical quantum yield of PSII (Fv/Fm) was affected by heat stress in the non-emitting clone (SMA130), while the INRA809 showed a significant resilience of PSII under elevated temperature conditions. Consistent data were recorded between field seasons and temperature treatments in controlled environment conditions, suggesting a strong influence of monoterpene emission on heat tolerance under high temperatures. This work provides further insights on the photoprotective role of isoprenoids in heat-stressed Vitis vinifera, and additional studies should focus on unraveling the mechanisms underlying heat tolerance on the monoterpene-emitter grapevine clone.

Understanding the physiological basis underlying the water stress responses in grapevine is becoming increasingly topical owing to the challenges that climate change will impose to grapevine agriculture. Here we used cv. Pinot gris (clone H1), grafted on a series of tolerant (1103Paulsen; P), sensitive (SO4) and recently selected (Georgikon28; G28, Georgikon121; G121, Zamor17; Z17) rootstocks. Plants were either subjected to reduced water availability (WS) or maintained at pot capacity (WW). Photosynthetic (light response curves), stomatal and in vivo gas exchange analysis were carried out as well as dynamics of daily water use (WU), leaf area accumulation with affordable RGB imaging pipelines and leaf water potential. Significant genotypic variation was recorded between rootstocks for most of the traits analyzed under optimal conditions with P and SO4 showing a more vigorous growth, higher CO2 assimilation rate, stomatal conductance and stomatal density per unit of leaf area than G28, G121, Z17 (p < 0.001). Under WS, rootstocks induced different water stress response in Pinot gris, with G28 and G121 showing a higher sensitivity of water use to reduced water availability (WS) (p = 0.021) and no variation for midday leaf water potential until severe WS. P, Z17 and to some extent SO4 induced a pronounced near-anisohydric response with a general WU maintenance followed by reduction in leaf water potential even at high levels of soil water content. In addition, G28 and G121 showed a less marked slope in the linear relationship between daily water use and VPD (p = 0.008) suggesting elevated sensitivity of transpiration to evaporative demand. This led to an insensitivity for total dry weight biomass of G28 and G121 under WS conditions (p < 0.001). This work provides: (i) an in-depth analysis for a series of preferable traits under WS in Pinot gris; (ii) a characterization of Pinot gris × rootstock interaction and a series of desirable traits under WS induced by several rootstocks; (iii) the potential benefit for the use a series of affordable methods (e.g., RGB imaging) to easily detect dynamic changes in biomass in grapevine and quickly phenotype genotypes with superior responses under WS. In conclusion, the near-isohydric and conservative behavior observed for G28 and G121 coupled with their low vigor suggest them as potential Pinot gris rootstock candidates for sustaining grapevine productivity in shallow soils likely to develop terminal stress conditions.

Rising temperatures and ozone levels are among the most striking stressful phenomena of global climate changes, and they threaten plants that are unable to react rapidly and efficiently. Generic responses of plants to stresses include the production of excess reactive oxygen species (ROS). Excessive ROS accumulation can lead to extensive oxidation of important components such as nucleic acids, proteins and lipids which can further exacerbate ROS accumulation leading to programmed cell death. Although most studies on plant antioxidants have focused on non-volatile compounds, volatiles belonging to the isoprenoid family have been implicated in the protection against abiotic stresses, in particular thermal and oxidative stress whose frequency and extent is being exacerbated by ongoing global change and anthropogenic pollution. Historically, research has focused on isoprene, demonstrating that isoprene-emitting plants are more tolerant to ozone exposure and heat stress, reducing ROS accumulation. Yet, evidence is being compiled that shows other volatile isoprenoids may be involved in plant responses against abiotic stresses. Grapevines are not isoprene emitters but some varieties produce other volatile isoprenoids such as monoterpenes. We investigated photosynthesis and emission of volatile organic compounds upon heat stress in two Vitis vinifera cv. ‘Chardonnay’ clones differing only for a mutation in the DXS gene (2-C-methyl-D-erythritol 4-phosphate (MEP) pathway), regulating volatile isoprenoid biosynthesis. We showed that the mutation led to a strong increase in monoterpene emission upon heat stress. At the same time, maximum photochemical quantum yield (Fv/Fm ratio) of PSII was affected by the stress in the non-emitting clone while the monoterpene emitter showed a significant resilience, thus indicating a possible antioxidant role of monoterpenes in grapevine. Future mechanistic studies should focus on unveiling the actual mechanism responsible for such findings.

This paper describes the accumulation pattern of 42 mineral elements in Vitis vinifera L. berries during development and ripening and their distribution in berry skin, seeds, and flesh around harvest time. Grape berries were sampled in two different vineyards with alkaline soil and analyzed using a ICP-MS. Although elemental amounts were significantly different in the grapes from the two vineyards, the accumulation pattern and percentage distribution in different parts of the berries were generally quite similar. Ba, Eu, Sr, Ca, Mg, Mn, and Zn accumulate prior to veraison. Al, Ce, Dy, Er, Ga, Gd, Ho, La, Nd, Pr, Sm, Sn, Zr, Th, Tm, U, Y, and Yb accumulate mainly prior to veraison but also during ripening. Ag, As, B, Cd, Cs, Cu, Fe, Ge, Hg, K, Li, Na, P, Rb, Sb, Se, and Tl accumulate progressively during growth and ripening. With regard to distribution, Ba, Ca, Eu, Fe, Mn, P, Sr, and Zn accumulate mainly in the seeds, Al, B, Ga, Sn, and the rare earths analyzed, except for Eu, accumulate mainly in the skin, and Ag, As, Cd, Cs, Cu, Ge, Hg, K, Li, Mg, Na, Rb, Sb, Se, Th, Tl, U, and Zr accumulate mainly in the flesh. A joint representation of the accumulation and distribution patterns for the elements in the berry is also given.