Water saving under drought stress is assured by stomatal closure driven by active (ABA-mediated) and/or passive (hydraulic-mediated) mechanisms. There is currently no comprehensive model nor any ...general consensus about the actual contribution and relative importance of each of the above factors in modulating stomatal closure in planta. In the present study, we assessed the contribution of passive (hydraulic) vs active (ABA mediated) mechanisms of stomatal closure in V. vinifera plants facing drought stress. Leaf gas exchange decreased progressively to zero during drought, and embolism-induced loss of hydraulic conductance in petioles peaked to ~50% in correspondence with strong daily limitation of stomatal conductance. Foliar ABA significantly increased only after complete stomatal closure had already occurred. Rewatering plants after complete stomatal closure and after foliar ABA reached maximum values did not induced stomatal re-opening, despite embolism recovery and water potential rise. Our data suggest that in grapevine stomatal conductance is primarily regulated by passive hydraulic mechanisms. Foliar ABA apparently limits leaf gas exchange over long-term, also preventing recovery of stomatal aperture upon rewatering, suggesting the occurrence of a mechanism of long-term down-regulation of transpiration to favor embolism repair and preserve water under conditions of fluctuating water availability and repeated drought events.
Knowledge of tree size is of great importance for the precision management of a hazelnut orchard. In fact, it has been shown that site-specific crop management allows for the best possible management ...and efficiency of the use of inputs. Generally, measurements of tree parameters are carried out using manual techniques that are time-consuming, labor-intensive and not very precise. The aim of this study was to propose, evaluate and validate a simple and innovative procedure using images acquired by an unmanned aerial vehicle (UAV) for canopy characterization in an intensive hazelnut orchard. The parameters considered were the radius (Rc), the height of the canopy (hc), the height of the tree (htree) and of the trunk (htrunk). Two different methods were used for the assessment of the canopy volume using the UAV images. The performance of the method was evaluated by comparing manual and UAV data using the Pearson correlation coefficient and root mean square error (RMSE). High correlation values were obtained for Rc, hc and htree while a very low correlation was obtained for htrunk. The method proposed for the volume calculation was promising.
Knowledge of crop water requirements is important in supporting irrigation management. Evapotranspiration (ET) is commonly measured with a variety of instruments and field procedures, but it is also ...typically computed or modeled using the FAO56 or FAO66 methods. The adoption of this approach requires the assessment of the crop coefficients. Some data are available for own-rooted hazelnut trees, but no data have been reported for young and grafted hazelnut trees. There is a need to update nut–tree crop coefficients, especially considering modern cultivars and production systems, such as those with a high tree density per ha−1. In this paper, the FAO66 crop transpiration coefficient Kc,Tr and the FAO56 dual crop coefficients Kcb were assessed for the mid-growing season of a young grafted hazelnut orchard. The field data were acquired manually and using UAV. The coefficients were determined for three tree densities and for two growing seasons. The crop coefficients, obtained using the FAO66 method, agreed with the literature data referring to low densities, while the FAO56 method could allow us to better define the crop coefficients for high-density hazelnut orchards.
Stone fruits of the Rosaceae family consist of several distinct parts, and these include the flesh, woody endocarp, and seed. To understand the metabolism of these fruits, it is necessary to have ...knowledge of both their structure and growth characteristics. The nitrogen metabolism of the different tissues of stone fruits is interlinked. For example, there is an import and storage of nitrogenous compounds in the endocarp that are then exported to the seed. Moreover, there are links between the metabolism of nitrogen and that of malic/citric acids. In this article, the structure and growth characteristics, together with the import/export, contents, metabolism, and functions of nitrogenous compounds and organic acids in the different parts of stone fruits and their seeds are reviewed.
Olive fruits of three different cultivars (Moraiolo, Dolce di Andria, and Nocellara Etnea) were monitored during ripening up to harvest, and specific and total phenols were measured by HPLC (High ...Pressure Liquid Chromatography). On the same olive samples (n = 450), spectral detections were performed using a portable NIR (Near Infrared)-AOTF (Acousto Optically Tunable Filter) device in diffuse reflectance mode (1100–2300 nm). Prediction models were developed for the main phenolic compounds (e.g., oleuropein, verbascoside, and 3,4-DHPEA-EDA) and total phenols using Partial Least Squares (PLS). Internal cross-validation (leave-one-out method) was applied for calibration and prediction models developed on the data sets relative to each single cultivar. Validation of the models obtained as the sum of the three sample sets (total phenols, n = 162; verbascoside, n = 162; oleuropein, n = 148; 3,4-DHPEA-EDA, n = 162) were performed by external sets of data. Obtained results in term of R 2 (in calibration, prediction and cross-validation) ranged between 0.930 and 0.998, 0.874–0.942, and 0.837–0.992, respectively. Standard errors in calibration (RMSEC), cross-validation (RMSECV), and prediction (RMSEP) were calculated obtaining minimum error in prediction of 0.68 and maximum of 6.33 mg/g. RPD ratios (SD/SECV) were also calculated as references of the model effectiveness. This work shows how NIR-AOTF can be considered a feasible tool for the on-field and nondestructive measurement of specific and total phenols in olives for oil production.
A trial was carried out in central Italy in an olive orchard of cultivar Moraiolo, highly infected by
. The aim of the investigation was to evaluate the effects of autumn and spring applications of ...copper oxychloride or dodine to control the disease. Non treated trees were used as the control. The effects of the fungal attacks on leaves and inflorescence development confirmed the high susceptibility of the cultivar Moraiolo to the disease. The results show that in trees heavily infected, but with most of the infected leaves at the early stage of the disease (asymptomatic phase), treatments with dodine had a curative effect, with consequent reduction in the appearance of symptomatic leaves and defoliation with respect to the control or copper-treated trees. The use of dodine against the autumnal attacks of
allowed most of the old leaves to be maintained until the new ones had formed, which is important for the growth processes during the early part of the growing season. Overall, the results indicate that to efficiently control the pathogen using copper compounds, treatments must start soon after the beginning of the attack and be repeated in order to maintain the infection at a low level. Dodine can be efficiently used if there is a great increase in infected leaves. The use of dodine to solve particular situations and not for normal repeated use is regulated by the fact that in some countries, Italy included, protocols for integrated pest management allow only one dodine treatment/year.
The demand for nuts has prompted the need to identify additional zones for hazelnut cultivation in Italy. There is great interest in the Abruzzo Region, in the central–eastern part of the country. ...The relationships between climate and environmental requirements for hazelnut were analyzed, taking into account the geography of the region, as well as climate change. The study was conducted by using the weather data from 34 stations between 1980 and 2019. The chilling requirements of the species are mostly met, except on the southern coast. Hot spring and summer caused an increase in the growing degree day in all locations. Years with minimum temperatures below −10 °C from December to March were almost null in coastal areas and the hilly belt. Late spring frosts in inland and mountainous areas occurred frequently, and the number of days with temperatures above 30 °C showed an upward trend everywhere. Five locations (Santo Stefano, Caramanico, Vasto, Isola del Gran Sasso, and Penne) were suitable for hazelnut cultivation, three were moderately suitable, seven were not very suitable, and nineteen were unsuitable.
In this study, the effects of climate change on the irrigation water requirement of hazelnut trees were investigated in Central Italy. The meteorological variables considered were precipitation, ...temperature, chilling units, and the Standardized Precipitation Index (SPI) in Central Italy. The hydrological variables were the reference evapotranspiration (ET0) and the water requirement based on soil water balance. Climate data were collected from eight meteorological stations for the period 1974–2021, and ET0 was estimated by the Hargreaves and Samani equation. The SPI index was calculated for a four-month time scale corresponding to the hazelnut growing season (April–August). A statistical analysis of the trends of the variables considered was conducted. The results showed an increasing trend for temperature, ET0, and water requirements, while a decreasing trend was shown for the chilling units. No significant trends were detected for precipitation and SPI.
► Sucrose synthase is the dominating enzyme for sucrose cleavage in growing kiwifruit. ► Sucrose synthase activity correlates non linearly with the fruit growth rate. ► Sucrose synthase activity ...correlate linearly with the activities of fructokinase and UDP glucose PPiase.
Changes in fruit growth rate, carbohydrate content (glucose, fructose, sucrose and starch) and enzyme activity (sucrose synthase, UDPglucose pyrophosphorylase, fructokinase, glucokinase, sucrose phosphate synthase, ADPglucose pyrophosphorylase and invertases), in the external pericarp of kiwifruit, were measured throughout the growing season. Sucrose synthase showed the highest activity among the sucrose cleaving enzymes during large part of the growing season. The activity of invertases were much lower than that of sucrose synthase until ripening started. Sucrose synthase showed a tight although not linear relationship with the fruit RGR. Furthermore, sucrose synthase showed linear and significant correlations with the activities of both fructokinase and UDPglucose pyrophosphorylase indicating a strong co-regulation of the activities of these three enzymes involved in sucrose cleavage and sink strength, in kiwifruit. Sucrose synthase is suggested to be the dominating enzyme in the cleavage of imported carbon in kiwifruit, in tight coordination with fructokinase and UDPglucose pyrophosphorylase.
Over the course of four consecutive years, a comparative study, for the first time, was carried out to assess their growth characteristics, vegetative and productive performances.IntroductionOver the ...course of four consecutive years, a comparative study, for the first time, was carried out to assess their growth characteristics, vegetative and productive performances.Micropropagated, grafted on not suckering rootstock and own-rooted plants by layering from three Italian hazelnut (Corylus avellana L.) cultivars were established in the same orchard and environmental condition.MaterialMicropropagated, grafted on not suckering rootstock and own-rooted plants by layering from three Italian hazelnut (Corylus avellana L.) cultivars were established in the same orchard and environmental condition.We found that the micropropagated plants, regardless of the variety considered, even being smaller than the other plants at the beginning of the plantation, reached similar sizes as the other plants after four growing seasons. Furthermore, micropropagated plants exhibited greater uniformity in growth compared to grafted ones, while own-rooted plants displayed more variability. No significant differences in yield performance and canopy volume were observed among the three propagation methods. These results suggest that the in vitro propagation technique, even in hazelnut, allows standardizing the plant material while preserving cultivar characteristics. Finally, in vitro propagation as well as grafting can be safely recommended for the cultivation of hazelnut cultivars.ResultsWe found that the micropropagated plants, regardless of the variety considered, even being smaller than the other plants at the beginning of the plantation, reached similar sizes as the other plants after four growing seasons. Furthermore, micropropagated plants exhibited greater uniformity in growth compared to grafted ones, while own-rooted plants displayed more variability. No significant differences in yield performance and canopy volume were observed among the three propagation methods. These results suggest that the in vitro propagation technique, even in hazelnut, allows standardizing the plant material while preserving cultivar characteristics. Finally, in vitro propagation as well as grafting can be safely recommended for the cultivation of hazelnut cultivars.
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