Comparing water relations and stomatal regulation of Touriga Nacional and Syrah under mild water stress

Proceedings - IX International Terroir Congress, 2012Aiming to compare the physiological responses of the Portuguese red variety Touriga Nacional (TN) with Syrah (SY), we studied during the 2007 growing season five-year-old grapevines growing in a commercial non-irrigated vineyard located at the Lisbon winegrowing region. Predawn (Ypd) and midday (YM) leaf water potential, leaf stomatal conductance (gs) and photosynthetic rate (A) were periodically measured between fruit set and harvest. Ypd displayed a decreasing pattern throughout the growing cycle from -0.10 MPa at flowering to -0.44 MPa at harvest. Both varieties showed similar values except during the two measurements made in August when TN presented significantly higher values than SY. Ymid also showed a decreasing pattern from the end of June towards harvest date, with significant differences between varieties being observed during the ripening period, with SY showing lower values than TN. A measured either at mid-morning and midday presented, for most part of the cases, lower values in SY than in TN, although the differences were only significant during the ripening period. gs pattern was parallel to A and, in general, the relative differences between varieties mirrored those reported for A. No significant effect of the variety was detected on the relationships between A or gs measured at mid-morning and Ypd. However, when analyzing the set of data collected at midday it was observed that the regression lines of the relationships between A or gs (dependent variables) and Ypd (independent variable) presented a significantly higher slope in SY as compared to those showed by TN. These results show that the rate of decrease of A and gs with the decrease of Ypd was lower in TN than in SY suggesting that the two varieties have different stomatal regulation, with a more “optimistic” behavior in TN

Dynamics of soil and canopy temperature: a conceptual approach for Alentejo vineyards

Context and purpose of the study - Climate change imposes increasing restrictions and risks to Mediterranean viticulture. Extreme heat and drought stress events are becoming more frequent which puts in risk sustainability of Mediterranean viticulture. Moreover row crops e.g. grapevine for wine, are increasingly prone to the impact of more intense/longer exposure time to heat stress. The amplified effects of soil surface energy reflectance and conductance on soil-atmosphere heat fluxes can be harmful for leaf and berry physiology. Leaf/canopy temperature is a biophysical variable with both physiological and agronomic meaning. Improved comprehension of spatial and temporal dynamics of soil and leaf/canopy temperature (thermal microclimate) in irrigated vineyards can support improved crop and soil monitoring and management under more extreme and erratic climate conditions. In this work we propose a conceptual approach to integrate information on major soil-vine-atmosphere interactions under deficit irrigation. Ultimately a conceptual model based on temperature relations is proposed to support assessment of the impact of air and soil temperatures on canopy and berry temperatures, leaf senescence and gas exchange. This model may support Decision Support Systems (DSS) for canopy and soil management and irrigation scheduling in Mediterranean vineyards. In addition a set of temperatures (e.g. canopy, soil) are proposed to feed the conceptual models to support the DSSinfo:eu-repo/semantics/publishedVersio

Canopy and soil thermal patterns to support management of irrigated vineyards

Irrigated viticulture expanded fast in Southern European countries such as Portugal to optimize berry yield and quality and to increase vine’s longevity. However, intensive irrigation increases pressure over the local and regional water resources, that are getting scarcer, and increases also management costs. Additionally, row crops such as grapevine, are more vulnerable to heat stress due to the additional effects of soil heat fluxes which can negatively influence canopy and berry thermal condition. Therefore, a better understanding of grapevine responses (diurnal and seasonal) to environmental factors (air temperature, soil water) and agronomic practices (deficit irrigation, soil management) are on demand by the industry. Ground based thermography was used to monitor the vertical profile of canopy temperature as well as soil temperature patterns along the day and season as means to assess plant water status and predict risks of heat stress damage. As part of the EU-INNOVINE project, field trials were carried in 2013, 2014 and 2015 in Alentejo (South Portugal). We examined the diurnal and seasonal response of two V. vinifera varieties Aragonez (syn. Tempranillo) and Touriga Nacional subjected to sustained deficit irrigation (SDI), and regulated deficit irrigation (RDI, about 50% of the SDI). Diurnal canopy (TC), and soil surface (Tsoil) temperatures were assessed by thermography. Punctual measurements of leaf temperature with thermal couples, leaf water potential and leaf gas exchange were also done. TC values were above the optimal temperature for leaf photosynthesis during part of the day light period (11:00-14:00h to 17:00h), especially under stressful atmospheric conditions (high VPD, high Tair) and under regulated deficit irrigation. Tsoil was on average about 10-15°C higher than TC. We found strong correlation between TC (derived from thermography) and major physiological traits (leaf water potential and leaf gas exchange). Our results suggest that Tc can be explored as a simple but robust non-intrusive thermal indicator of grapevine performance and also as a parameter to feed grapevine growth models and to estimate heat and water fluxes in irrigated vineyardsinfo:eu-repo/semantics/publishedVersio

Can soil water content be used as a predictor of predawn leaf water potential for deficit irrigation scheduling? A case study at Alentejo wine region

Context and purpose of the study: Water and heat stress impose new challenges to irrigation management in the Mediterranean areas. This reality has a major impact on the vineyard ecosystem, particularly on the scarce water resources of the Alentejo region (South Portugal). To mitigate this problem, irrigation management should focus on optimizing yield and fruit quality per volume of water applied. This work aims to discuss the use of predawn leaf water potential and soil water status relationships as a decision tool for irrigation management taking as basis data from a field trial where two deficit irrigation strategies were comparedinfo:eu-repo/semantics/publishedVersio

Is early defoliation a sustainable management practice for mediterranean vineyards? case studies at the portuguese Lisbon winegrowing region

Context and purpose of the study - Recently early defoliation (ED) has been tested in several highyielding grapevine varieties and sites aiming at reducing cluster compactness and hence, regulating yield and susceptibility to botrytis bunch rot infection. The reported results have been generally positive, encouraging growers to use this canopy management technique as an alternative for replacing the conventional time-consuming cluster thinning and, simultaneously, as a sustainable practice to reduce the use of fungicides. However, ED increases berry sunburn risks and/or can induce carry-over effects on vigor and node fruitfulness as shown in the two case studies reported in this work. Material and methods- Two ED experiments were set up at a commercial vineyard located in the Lisbon winegrowing region with the varieties Aragonez, syn. Tempranillo (2013-2015) and Semillon (2018). In both experiments the ED treatment was compared with the non-defoliated (ND; control) using a randomized complete block design with 4 replicates per treatment. The ED treatment consisted of the removal of 5-6 basal leaves and any laterals at pre-flowering. Vegetative (leaf area and pruning weight) and reproductive components (%fruit-set, cluster number, cluster weight, yield) and berry composition were assessedinfo:eu-repo/semantics/publishedVersio

Tempranillo physiological and agronomical responses to heat and drought stress – perspectives on its vulnerability under climate change scenarios

With the aim to characterize the ability of Tempranillo grapevines, one of the most widely used varieties in Spain and Portugal, to withstand drought and heat stress, ecophysiological and agronomical data from irrigation experiments conducted in the hot and dry region of Alentejo, south of Portugal, are presented. The impact of different irrigation treatments on physiological parameters (leaf water potential, photosynthesis, and stomatal conductance) and water use efficiency are showed. Leaf senescence observed in non-irrigated and deficit irrigated plants and its consequences on cluster exposure and berry temperature are compared with those of fully irrigated plants. The consequences on berry ripening and juice composition are discussed in order to evaluate the vulnerability of Tempranillo to the expected global climatic changeinfo:eu-repo/semantics/publishedVersio

Evaluation of the oxidative profile in leukocytes of jiu jtisu athletes

Oxidative stress is a process where there is an increase in reactive species, both oxygen and nitrogen. This can happen at both systemic and mitochondrial levels. One of the physiological conditions currently associated with oxidative stress is high-performance physical activity. In this way, it is possible to relate that this problem impacts on sports competitions, especially in Jiu-Jitsu, a growing sport in the world and which demands intense physical effort. Thus, the objective was to evaluate the level of mitochondrial and systemic oxidation in leukocytes of jiu-jitsu athletes. 20 adult men were selected for the control group and 13 athletes for the experimental group. A blood collection was performed to perform MTT and chemiluminescence assays for an analysis of mitochondrial and systemic oxidation, respectively. In addition, two reactive nitrogen species were measured: nitric oxide and peroxynitrite. The evaluation of the leukocyte reducing capacity by MTT showed that the athletes presented a greater reducing environment compared to the control. On the other hand, the chemiluminescence evaluation showed that the athletes' leukocytes showed greater systemic oxidation. There was an increase in both reactive nitrogen species in alteta leukocytes. Given this, it was possible to notice that the athletes presented greater systemic oxidative stress, but with mitochondria with better adaptive capacity to the cell's metabolic demands

Yoga for Vital Capacity

The purpose of this study was to ascertain the effect of yogic exercises and pranayam on the vital capacity adolescent school going boys. In total 60 numbers of school students (boys only) were taken as subjects and were divided equally (30 each) into two groups namely Experimental and Control groups. Pre tests on Vital Capacity was conducted prior to Yogic exercises and pranayam treatment to the experimental group and post test was made after a 12 week treatment and comparisons were made between and within the groups using descriptive statistics and Factorial ANOVA. It was concluded that Yoga Training Group (Experimental Group) improves Vital Capacity of adolescent student

Effects of soil management and deficit irrigation strategies on physiological and agronomical responses of Aragonez field-grown grapevines

The use of irrigation in Mediterranean viticulture is now a common practice in intensive grapevine production to improve quality of production. The negative effects of water deficits on grape berry development are well known but the underlying mechanisms remain not fully understood. To avoid the unfavourable impacts of mechanization on the soil structure and biology some farmers are using cover crops on their vineyards. Within this frame we have compared the traditional soil tillage with a high level of mechanization with other system where we maintained a permanent soil cover between the rows. In both soil systems we tested three different irrigation treatments, deficit irrigation (DI - 40% of evapotranspiration (ETc)); regulated deficit irrigation (RDI); partial root drying (PRD) while in the soil cover treatment we also studied the full irrigation (FI) and the non irrigation (NI) treatments. Compared to soil tillage the resident vegetation reduced soil water content during late Spring, before irrigation started, inducing a significant reduction on vine vegetative growth berry weight and yield. Among irrigation strategies only RDI treatment showed a significant reduction in the lateral leaf area development, berry weight and yield when compared to PRD and DI treatments which presented similar values. No significant differences were observed in berry composition either for the two floor management practices or for the three irrigation strategiesinfo:eu-repo/semantics/publishedVersio

Response of growth, yield and berry composition to basal leaf removal in Jaen grapevine

Results from a leaf removal experiment located at Dão Winegrowing region of Portugal are presented. Three intensity levels of defoliation (control non-defoliated, leaves removed up to the third basal node and up to the sixth basal node) are compared. Defoliation treatments had no significant effect on yield and on must soluble solids, showing that the remaining leaves were able to guarantee berry development and sugar accumulation in the fruit. The more intense defoliation treatment induced favorable effects on light microclimate in the cluster zone, with positive consequences for polyphenols synthesis and reduction of Botrytis cinerea Pers. incidenceinfo:eu-repo/semantics/publishedVersio