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.
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.
Casuarina glauca is an actinorhizal tree which establishes root-nodule symbiosis with N2-fixing Frankia bacteria. This plant is commonly found in saline zones and is widely used to remediate marginal ...soils and prevent desertification. The nature of its ability to survive in extreme environments and the extent of Frankia contribution to stress tolerance remain unknown. Thus, we evaluated the ability of C. glauca to cope with salt stress and the influence of the symbiosis on this trait. To this end, we analysed the impact of salt on plant growth, mineral contents, water relations, photosynthetic-related parameters and non-structural sugars in nodulated vs. non-nodulated plants. Although the effects on photosynthesis and stomatal conductance started to become measurable in the presence of 200 mM NaCl, photochemical (e.g., photosynthetic electron flow) and biochemical (e.g., activity of photosynthetic enzymes) parameters were only strongly impaired when NaCl levels reached 600 mM. These results indicate the maintenance of high tissue hydration under salt stress, probably associated with enhanced osmotic potential. Furthermore, the maintenance of photosynthetic assimilation potential (Amax), together with the increase in the quantum yield of down-regulated energy dissipation of PSII (YNPQ), suggested a down-regulation of photosynthesis instead of photo-damaging effects. A comparison of the impact of increasing NaCl levels on the activities of photosynthetic (RubisCO and ribulose-5 phosphate kinase) and respiratory (pyruvate kinase and NADH-dependent malate dehydrogenase) enzymes vs. photosynthetic electron flow and fluorescence parameters, revealed that biochemical impairments are more limiting than photochemical damage. Altogether, these results indicate that, under controlled conditions, C. glauca tolerates high NaCl levels and that this capacity is linked to photosynthetic adjustments.
•Casuarina glauca tolerates seawater levels of salt.•Salt tolerance is innate at least under controlled environmental conditions.•Salt tolerance is linked to the down-regulation of photosynthetic functioning.•Biochemical impairments are more limiting than photochemical damage.•This is the first in depth report on the impact of salt stress in C. glauca.
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.
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.
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 (Pn). 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.
Bread wheat (
) is a major crop worldwide, and it is highly susceptible to heat. In this work, grain production and composition were evaluated in Portuguese
germplasm (landraces and commercial ...varieties), which was subjected to heat after anthesis (grain filling stage). Heat increased the test weight (TW) in Nabão, Grécia and Restauração, indicating an improved flour-yield potential. Mocho de Espiga Branca (MEB) and Transmontano (T94) showed higher thousand-kernel weight (TKW). Gentil Rosso presented increased soluble sugars, which are yeast substrates in the bread-making process. Ardila stood out for its protein increase under heat. Overall SDS was unaffected by higher temperature, but increased in T94, indicating a better dough elasticity for bread-making purposes. Under heat, lipid content was maintained in most genotypes, being endogenous fatty acids (FAs) key players in fresh bread quality. Lipid unsaturation, evaluated through the double bond index (DBI), also remained unaffected in most genotypes, suggesting a lower flour susceptibility to lipoperoxidation. In Grécia, heat promoted a higher abundance of monounsaturated oleic (C18:1) and polyunsaturated linoleic (C18:2) acids, which are essential fatty acids in the human diet. This work highlighted a great variability in most parameters both under control conditions or in response to heat during grain filling. Cluster analysis of traits revealed a lower susceptibility to heat during grain filling in Ardila, Restauração, and Ruivo, in contrast to MEQ, which seems to be more differentially affected at this stage. Characterization and identification of more favorable features under adverse environments may be relevant for agronomic, industrial, or breeding purposes, in view of a better crop adaptation to changing climate and an improved crop sustainability in agricultural systems more prone to heat stress.
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.
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.
An agronomic itinerary for Se biofortification of two rice cultivars (Ariete and Ceres) through foliar fertilization with sodium selenate and sodium selenite with different concentrations (25, 50, 75 ...and 100 g Se.ha
), was implemented in experimental fields. The selenium toxicity threshold was not exceeded, as shown by the eco-physiological data obtained through leaf gas exchanges. The highest Se enrichment in paddy grains was obtained with selenite for both cultivars, especially at the highest doses, i.e., 75 and 100 g Se.ha
, with approximately a 5.0-fold increase compared with control values. In paddy grains, Zn was the most affected element by the treatments with Se with decreases up to 54%. When comparing the losses between rough and polished grains regardless of the cultivars, Se species and concentrations, it was observed that only Cu, Mg and Zn exhibited losses <50%. The remaining elements generally had losses >70%. The loss of Se is more pronounced in Ceres cultivar than in Ariete but rarely exceeds 50%. The analysis by µ-EDXRF showed that, in Ariete cultivar, Se is mostly homogeneously distributed in the grain regardless of any treatments, while in Ceres cultivar, the Se distribution seems to favor accumulation in the periphery, perhaps in the bran.
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