Search Results (52)

Zinc enrichment of edible food products, through the soil and/or foliar application of fertilizers, is a strategy that can increase the contents of some nutrients, namely Zn. In this context, a workflow for agronomic enrichment with zinc was carried out on irrigated Vitis vinifera cv. Syrah, aiming to evaluate the mobilization of photoassimilates to the winegrapes and the consequences of this for winemaking. During three productive cycles, foliar applications were performed with ZnSO₄ or ZnO, at concentrations ranging between 150 and 1350 g.ha⁻¹. The normal vegetation index as well as some photosynthetic parameters indicated that the threshold of Zn toxicity was not reached; it is even worth noting that with ZnSO₄, a significant increase in several cases was observed in net photosynthesis (P_n). At harvest, Zn biofortification reached a 1.2 to 2.3-fold increase with ZnSO₄ and ZnO, respectively (being significant relative to the control, in two consecutive years, with ZnO at a concentration of 1350 g.ha⁻¹). Total soluble sugars revealed higher values with grapes submitted to ZnSO₄ and ZnO foliar applications, which can be advantageous for winemaking. It was concluded that foliar spraying was efficient with ZnO and ZnSO₄, showing potential benefits for wine quality without evidencing negative impacts. Full article

There is a growing need for strategic actions involving efficient water use, sustainable agricultural production, and food security. Agricultural productivity can be improved through good agricultural practices based on water-quality management, new genetically modified resources, and using precision agriculture. This study aimed to monitor the crop water (supply, irrigation, and flooding) of an advanced rice (Oryza sativa L.) line of the breeding program (OP 1509) subjected to Selenium (Se) enrichment. Water lines in a paddy rice field were monitored by Unmanned Aerial Vehicles (UAVs). The parameters of pH, pHs, electrical conductivity, temperature, HCO₃⁻, Cl⁻, SO₄²⁻, PO₄³⁻, Na⁺, K⁺, Ca²⁺, and Mg²⁺ were analyzed. According to the Piper diagram, the samples were classified as sodium chloride bicarbonate (supply) and sodium bicarbonate chloride (irrigation and flooding). The Langelier Saturation Index (LSI) was calculated and indicated that waters are good to use in agricultural practices. According to the Wilcox classification, regarding agriculture use, the samples were classified as C2S1 (supply and irrigation) and C3S1 (flooding). The Selenium contents were analyzed by atomic absorption and significant differences were observed in rice grains, with a maximum content of 10 mg.kg⁻¹. In conclusion, the water quality is in accordance with the parameters for use in this crop and the workflow used improved the grain quality. Full article

Tackling human malnutrition resulting from mineral deficits in foods is currently an agro-industrial problem. To address this problem, an agronomic workflow to enrich Rocha pears with calcium (Ca) was considered in two orchards in Portugal. This study aims to assess quality differences in the irrigation water of two orchards (of Rocha pear) where an agronomic Ca enrichment workflow would be performed and identify possible conditioning to Ca increases in fruits. Thus, electrical conductivity (EC), pH, pHs, cations (Na⁺, K⁺, Ca²⁺, and Mg²⁺), and anions (HCO₃⁻, Cl⁻, and SO₄²⁻) were attained to calculate the Sodium Adsorption Ratio (SAR) index and the Langelier Saturation Index (LSI) and assess the agricultural use. The values of EC, pH, pHs, SAR index and LSI of both orchards varied between 1198 and 1211 µS/cm, 7.4 and 7.5, 7.7 and 8.1, 3.5 and 7.4, and −0.69 and −0.21, respectively. Regarding Piper classification, irrigation waters were classified as sodium bicarbonate (orchard 1) and sodium chloride bicarbonate (orchard 2). Both orchards presented different classifications regarding agricultural use, namely C3S1 (orchard 2) and C3S2 (orchard 1). The water of both orchards presented the same salinity hazard (C3), but the use of these irrigation waters is enabled since these trees can be considered salt-tolerant. However, regarding the alkalinization hazard to soils, the irrigation water from orchard 2 offers less danger (S1) in comparison to orchard 1 (S2). Meanwhile, a slightly inferior LSI (orchard 1) can favor a higher tendency to dissolve calcium carbonate. In conclusion, although slightly different, analysis indicated that the waters of both orchards did not induce toxicity in Rocha pear trees. Full article

Potato (Solanum tuberosum L.) is a widely consumed and essential food crop globally, making it an ideal food matrix for biofortification. Agronomic biofortification is one of the strategies used to enhance Ca content in edible parts of crops, considering the adverse health issues associated with Ca deficiency. This study aims to investigate the impact of Ca agronomic biofortification through four foliar applications after the beginning of tuberization on the yield of tubers of Solanum tuberosum L. (Picasso variety) produced in Lourinhã (Portugal) in 2018, focusing on the application of calcium chloride or, alternatively, calcium nitrate at different concentrations (calcium chloride—1, 3, 6 and 12 kg/ha or calcium nitrate—0.5, 1, 2 and 4 kg/ha). Control plants and plants subjected to the different Ca treatments were placed in plots of 20 × 24 m; the treatments were carried out in quadruplicate (compass 60–80 cm). As such, the Ca content in tubers was quantified by atomic absorption spectrophotometry in the different treatments. The Ca biofortification index with calcium chloride or calcium nitrate ranged between 5 and 40%, with the treatment with 6 kg/ha CaCl₂ being the one which presented the highest Ca content in tubers at harvest and 1 kg/ha CaCl₂ being the treatment with the lowest Ca biofortification index. However, 6 kg/ha CaCl₂, despite presenting the highest Ca content, was not the treatment that presented the highest yield. Indeed, all the calcium nitrate treatments demonstrated a substantial increase in tubers yield, which varied between 2.3 (4 kg/ha Ca(NO₃)₂) and 24.3% (2 kg/ha Ca(NO₃)₂). Statistical analysis was carried out in all the analyses using one-way ANOVA to assess differences among treatments in Solanum tuberosum L. (Picasso variety), followed by Tukey’s analysis for mean comparison, with a 95% confidence level. Furthermore, these findings emphasize the potential of Ca biofortification, especially calcium nitrate treatments, in enhancing the yield of Solanum tuberosum L. tubers. Full article

Remote sensing technology (namely UAVs) has been used to monitor potato crops. As such, this study aims to analyze the relationship between the NDVI model and yield productivity in Solanum tuberosum L. plants from the Agria variety, submitted to a Ca biofortification process with two different concentrations (12 and 24 kg/ha) of CaCl₂ or Ca-EDTA. The NDVI values were collected six days after the six foliar applications and analyzed alongside the Ca content in the potato tubers (at harvest) and the total yield. The results highlight the fact that 24 kg/ha of CaCl₂ presented the lowest NDVI value, yet these plants did not show the lowest yield. Moreover, that same treatment presented the highest Ca biofortification index in tubers. Also, it seems that the NDVI can be used in decision making to improve crop management strategies, considering that it is an indicator for detecting plant growth or vigor; however, in this research, it is not sufficient for yield prediction. Full article

Human malnourishment is a current problem of society, and agronomic biofortification is a procedure that wishes to tackle these mineral deficits in human diets by increasing a specific nutrient in the edible part of food crops. Calcium is an important mineral element that performs structural functions and thus can help prevent the development of pathologies such as osteoporosis. Thereby, this work aims to study the impact of calcium enrichment on fatty acid (FA) content in Rocha pears. Thus, an agronomic enrichment workflow with seven foliar sprays of CaCl₂ (with concentrations between 4–8 kg/ha) was performed in an orchard located in the western region of Portugal. Besides Ca enrichment assessment in fruits (with a portable X-ray fluorescence analyzer) at harvest, fatty acids quantification and FA profile (acquired with a gas–liquid chromatograph, coupled to a flame ionization detector (GC-FID)), double bond index (DBI), and lipoperoxidation values (with a spectrophotometer) were also attained. Increases of Ca in sprayed fruits reached 7.6% to 44.3%. For FA-related parameters, no significant differences were observed, suggesting that Ca sprays did not impact these parameters. Total fatty acids (TFA), DBI, and lipoperoxidation values varied between 0.72–0.74 g/100 g FW, 8.13–9.83 and 2.23–3.18 µM/g FW, respectively. The following FA profile was attained: C18:2 > C16:0 > C18:3 > C18:0 > C18:1 > <C16:0. No significant differences were observed. In summary, CaCl₂ can be used to increase Ca levels in fruits, allowing the production of fruits with prophylactic characteristics, while the concentrations from this study did not impact their FA content. Overall, this suggests that cell compartmentation and membranes’ regular functioning were maintained, suggesting the absence of lipid decay and avoiding a potential increase in storage losses. Full article

Remote sensing data are powerful tools that contribute to sustainability and efficiency in crop management. Rice (Oryza sativa L.) is widely recognized as one of the most important crops in terms of economic and social impact. The aim of this study was to evaluate the efficiency of the use of Unmanned Aerial Vehicles (UAVs) in providing valuable information regarding plant health and status with respect to two rice varieties (Ariete and Ceres) submitted to a biofortification workflow with two types of selenium (sodium selenate and sodium selenite). In this context, through the use of synchronized UAVs, the state of the culture was further assessed. As well, digital elevation models, water lines, slope classes/infiltration suitability, and the Normalized Difference Vegetation Index (NDVI) were considered. Additionally, leaf gas exchange measurements were conducted during the biofortification process and Se content in rice was quantified. The NDVI index ranged from 0.76 to 0.80, with no significant differences regarding control. The water drainage pattern following the artificial pattern created by grooves between plots was observed. Furthermore, selenite application up to 100 g Se.ha⁻¹ did not exhibit toxicity effects on the biofortified plants and presented grain enrichment of 16.09 µg g⁻¹ (Ariete) and 15.46 µg g⁻¹ (Ceres). In conclusion, precision agriculture techniques and the utilization of data from leaf gas exchanges allow for efficient monitoring of experimental field conditions and are highly useful tools in decision-making. Full article

Rice (Oryza sativa L.) is one of the most economically and socially important cereals in the world. Several strategies such as biofortification have been developed in a way eco-friendly and sustainable to enhance crop productivity. This study implemented an agronomic itinerary in Ariete and Ceres rice varieties in experimental fields using the foliar application of selenium (Se) to increase rice nutritional value. At strategic phases of the plant’s development (at the end of booting, anthesis, and at the milky grain stage), they were sprayed with sodium selenate (Na₂SeO₄) and sodium selenite (Na₂SeO₃). In the first foliar application plants were sprayed with 500 g Se·ha⁻¹ and in the remaining two foliar applications were sprayed with 300 g Se·ha⁻¹. The effects of Se in the level of micro and macronutrients in brown grains, the localization of Se in these grains, and the subsequent quality parameters such as colorimetric characteristics and total protein were considered. After grain harvesting, the application of selenite showed the highest enrichment in all grain with levels reaching 17.06 µg g⁻¹ Se and 14.28 µg g⁻¹ Se in Ariete and Ceres varieties, respectively. In the Ceres and Ariete varieties, biofortification significantly affected the K and P contents. Regarding Ca, a clear trend prevailed suggesting that Se antagonizes the uptake of it, while for the remaining elements in general (except Mn) no significant differences were noted. Protein content increased with selenite treatment in the Ariete variety but not in Ceres. Therefore, it was possible to conclude, without compromising quality, that there was an increase in the nutritional content of Se in brown rice grain. Full article

One-third of the world’s population is suffering from “hidden hunger” due to micronutrient deficiency. Zinc is acquired through diet, leading its deficiency to the development of disorders such as retarded growth, anorexia, infections, and hypogeusia. Accordingly, this study aimed to develop an agronomic workflow for Zn biofortification on two red winegrapes varieties (cv. Castelão and Syrah) and determine the physicochemical implications for winemaking. Both varieties produced in Setúbal (Portugal) were submitted to four foliar applications of ZnSO₄ or ZnO (900 and 1350 g ha⁻¹, respectively), during the production cycle. At harvest, Zn biofortification reached a 4.3- and 2.3-fold increase with ZnO 1350 g ha⁻¹ in Castelão and Syrah, respectively (although, with ZnSO₄ 1350 g ha⁻¹ both varieties revealed an increase in Zn concentration). On a physiological basis, lower values of NDVI were found in the biofortified grapes, although not reflected in photosynthetic parameters with cv. Syrah shows even a potential benefit with the use of Zn fertilizers. Regarding physical and chemical parameters (density, total soluble solids, dry weight, and color), relative to the control no significant changes in both varieties were observed, being suitable for winemaking. It was concluded that ZnSO₄ and ZnO foliar fertilization efficiently increased Zn concentration on both varieties without a negative impact on quality, but cv. Castelão showed a better index of Zn biofortification and pointed to a potentially higher quality for winemaking. Full article

Calcium is one of the 16 essential elements for plants, being required as Ca²⁺ and being involved in several fundamental processes (namely, in the stability and integrity of the cell wall, the development of plant tissue, cell division, and in stress responses). Moreover, Ca plays an important role in potato production. In this context, this study aimed to monitor the culture development (in situ and using an unmanned aerial vehicle (UAV)) and the mineral content of four essential elements (Ca, P, K, and S) in different organs of Solanum tuberosum L. (roots, stems, leaves, and tubers) during a calcium biofortification process, carried out with two types of solutions (CaCl₂ and Ca-EDTA) with two concentrations (12 and 24 kg∙ha⁻¹). The calcium content generally increased in the S. tuberosum L. organs of both varieties and showed, after the last foliar application, an increase in Ca content that varied between 5.7–95.6% and 20.7–33%, for the Picasso and Agria varieties, respectively. The patterns of accumulation in both varieties during the biofortification process were different between the variety and mineral element. Regarding the quality analysis carried out during the development of the tubers, only the Agria variety was suitable for industrial processing after the last foliar application. Full article

Following an agronomic approach for the Ca enrichment of Rocha pears, this study aimed to assess the interactions between mineral nutrients in fruit tissues at harvest and after storage for 5 months and to characterize the implications on the profile of sugars and fatty acids (FA). A total of seven foliar sprays (with concentrations of 0.1–0.6 kg·ha⁻¹ Ca(NO₃)₂ and 0.8–8 kg·ha⁻¹ CaCl₂) were applied to pear trees. After harvest, the fruits were stored for 5 months, in environmentally controlled chambers, and the mineral contents in five regions (on the equatorial section) of the fruits were assessed, while the sugar and FA content were quantified. For both dates, all foliar sprayed treatments, at different extends, increased Ca content in the center and near the epidermis of Rocha pear fruits and the levels of K, Mn, Fe, Zn and Cu also varied. At harvest, the Ca treatments did not affect the levels of sucrose, glucose, fructose and sorbitol and, after storage, their concentrations remained higher in Ca-treated fruits. Additionally, the tendency of the relative proportions of FA was C18:2 > C18:1 > C16:0 > C18:3 > C18:0 > chains inferior to 16 C (<16:0), but after storage it was C18:2 > C16:0 > C18:3 > C18:0 > C18:1 > chains inferior to 16 C (<16:0). It is concluded that the heterogeneous distribution of Ca in the tissues of Rocha pear fruits results from its absorption in the peel after Ca(NO₃)₂ and CaCl₂ sprays and from the xylemic flux in the core prior to maturity. Additionally, the hydrolysis of complex polysaccharides affects the contents of simpler sugars during maturation, ripening and senescence, while storage decreases the amount of total fatty acids (TFA), but the double bond index (DBI) indicate that cell membrane fluidity remains unaffected. Full article

Nowadays, there is a growing concern about micronutrient deficits in food products, with agronomic biofortification being considered a mitigation strategy. In this context, as Zn is essential for growth and maintenance of human health, a workflow for the biofortification of grapes from the Vitis vinifera variety Fernão Pires, which contains this nutrient, was carried out considering the soil properties of the vineyard. Additionally, Zn accumulation in the tissues of the grapes and the implications for some quality parameters and on winemaking were assessed. Vines were sprayed three times with ZnO and ZnSO₄ at concentrations of 150, 450, and 900 g ha⁻¹ during the production cycle. Physiological data were obtained through chlorophyll a fluorescence data, to access the potential symptoms of toxicity. At harvest, treated grapes revealed significant increases of Zn concentration relative to the control, being more pronounced for ZnO and ZnSO₄ in the skin and seeds, respectively. After winemaking, an increase was also found regarding the control (i.e., 1.59-fold with ZnSO₄-450 g ha⁻¹). The contents of the sugars and fatty acids, as well as the colorimetric analyses, were also assessed, but significant variations were not found among treatments. In general, Zn biofortification increased with ZnO and ZnSO₄, without significantly affecting the physicochemical characteristics of grapes. Full article

As the productivity and quality of tomato fruits are responsive to Mg applications, without surpassing the threshold of toxicity, the assessment of potential levels of Mg accumulation in tissues, as well as the interactions with Ca and physicochemical properties, prompt this study. An agronomic workflow for Mg enrichment, consisting of six foliar applications of MgSO₄ with four concentrations (0%, 0.25%, 1% and 4%), equivalent to 0, 43.9, 175.5 and 702 g ha⁻¹_, was applied on two tomato (Lycopersicum esculentum L.) genotypes (Heinz1534 and Heinz9205). During fruit development, leaf gas exchange was screened, with only minor physiological deviations being found. At harvest, Mg contents among tissues and the interactions with Ca were analyzed, and it was found that in both varieties a higher Mg/Ca ratio prevailed in the most external part of the fruit sprayed with 4% MgSO₄. However, Mg distribution prevailed relatively near the epidermis in H1534, while in H9205 the higher contents of this nutrient occurred in the core of the fruit, which indicated a decrease of the relative proportion of Ca. The morphologic (height and diameter), physical (dry weight and density) and colorimetric parameters, and the total soluble solids of fruits, did not reveal significant changes in both tomato varieties. It was further concluded that foliar application until 4% MgSO₄ does not have physiological impacts in the fruit’s quality of both varieties, but in spite of the different patterns of Mg accumulation in tissues, if the mean value in the whole fruit is considered, this nutrient prevails in H1534. This study thus suggests that variety H1534 can be used to attain tomato fruits with added value, providing an option of further processing to achieve food products with functional properties, ultimately proving a beneficial option to producers, the food processing industry and consumers. Moreover, the study reinforces the importance of variety choice when designing enrichment workflows. Full article

Calcium is essential for plants, yet as its mobility is limited, the understanding of the rate of Ca²⁺ accumulation and deposition in tissues of tubers, as well as the interactions with other critical nutrients prompted this study. To assess the interactions and differential accumulation of micro and macronutrients in the tissues of tubers, Solanum tuberosum L. varieties Agria and Rossi were cultivated and, after the beginning of tuberization, four foliar sprayings (at 8–10 day intervals) with CaCl₂ (3 and 6 kg ha⁻¹) or Ca(NO₃)₂ (2 and 4 kg ha⁻¹) solutions were performed. It was found that both fertilizers increased Ca accumulation in tubers (mostly in the parenchyma tissues located in the center of the equatorial region). The functioning of the photosynthetic apparatus was not affected until the 3rd application but was somewhat affected when approaching the end of the crop cycle (after the 4th application), although the lower dose of CaCl₂ seemed to improve the photochemical use of energy, particularly when compared with the greater dose of Ca(NO₃)₂. Still, none of these impacts modified tuber height and diameter. Following the increased accumulation of Ca, in the tubers of both varieties, the mean contents of P, K, Na, Fe, and Zn revealed different accumulation patterns. Moreover, accumulation of K, Fe, Mn, and Zn prevailed in the epidermis, displaying a contrasting pattern relative to Ca. Therefore, Ca accumulation revealed a heterogeneous trend in the different regions analyzed, and Ca enrichment of tubers altered the accumulation of other nutrients. Full article

Grapes and wine are widely consumed in the world, yet their mineral content can be influenced by many factors such as the mineral composition of soils, viticulture practices and environmental conditions. In this context, considering the importance of Zn in the human physiology, the enrichment of Moscatel and Castelão grapes (white and red variety, respectively) with this nutrient prompted this study; further assessment of tissue deposition and some implications for wine production. Using two foliar fertilizers (ZnO or ZnSO₄, at 150, 450 and 900 g ha⁻¹), decreases in net photosynthesis and stomatal conductance occurred in both varieties, suggesting that the physiological threshold of Zn toxicity was reached without visible symptoms. Following foliar spraying with both fertilizers, the content of Zn in leaves of the Castelão and Moscatel varieties showed higher values in all treatments relative to the control. Moreover, in grapes this tendency occurred only in Castelão. Concerning Cu, Fe, Ca, K, S and P, some significant differences also happened in leaves and grapes among treatments. At harvest, the indexes of Zn enrichment in grapes increased between 2.14- and 8.38-fold and between 1.02- and 1.44-fold in Castelão and Moscatel varieties, respectively. Zinc in the dried skin of Castelão only increased with ZnO and ZnSO₄ sprayed at 900 g ha⁻¹ (ca. 2.71- and 1.5-fold relative to the control, respectively), but in Moscatel a clear accumulation trend could not be found. The dry weight of grapes ranged (in %) between 16 and 23 (but did not vary significantly among treatments of each variety or in each treatment between varieties), and total soluble solids (e.g., mainly soluble sugars and proteins) and color parameters showed some significant variations. Through winemaking, the contents of Zn increased in both varieties (1.34- and 3.57-fold, in Castelão and Moscatel, respectively) and in all treatments, although non-significantly in Castelão. It is concluded that, to increase the contents of Zn in grapes without reaching the threshold of toxicity, ZnO or ZnSO₄ can be used for foliar spraying of Castelão and Moscatel varieties until 900 g ha⁻¹ and that winemaking augments the level of this nutrient. Full article