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The excessive use of chemical fertilizers in the Guanxi honey pomelo production area has led to severe soil acidification and magnesium (Mg) deficiency, adversely affecting pomelo fruit quality. To address this issue, an integrated nutrient optimization model crucial for ensuring the sustainable and environmentally friendly development of the Guanxi honey pomelo industry has been explored. In a three-year experiment, two fertilizer treatments were implemented: a farmer fertilizer practice (FP) and an NPK reduction plus foliar Mg fertilizer (OPT + fMg). We investigated the impact of this integrated optimized fertilization measure on pomelo fruit quality from three aspects: flavor (sugars and organic acids), nutrition (vitamin C and mineral elements), and antioxidant properties (phenolics, flavonoids, and phytic acid). The results revealed that the OPT + fMg treatment improved fruit flavor by reducing acidity (titratable acid, citric acid, and quinine), while having a minimal impact on sugar components (sucrose, fructose, and glucose). Additionally, the OPT + fMg treatment increased the total phenolics, total flavonoids, and phytic acid in the fruit peel, enhancing its potential antioxidant quality. However, the OPT + fMg treatment reduced the mineral nutrient quality (excluding calcium) in the fruit. As for the fruit developmental period, the OPT + fMg treatment significantly increased the total flavonoid concentration in the peel from the mid-expansion fruit stage, followed by notable increases in phytic acid in the peel during the mid-to-late expansion fruit stage. The total phenolic concentration in the peel significantly rose only during the late fruit development stage. The most pronounced effect was observed on phytic acid in both peel and pulp. The influence of the OPT + fMg treatment on the mineral nutrients (excluding calcium) primarily occurred during the mid-to-late expansion fruit stage. Overall, the OPT + fMg treatment significantly improved the comprehensive nutritional quality of pomelo fruit, providing valuable insights for scientifically reducing fertilizer application while enhancing fruit quality. [ABSTRACT FROM AUTHOR]

Agronomic properties are more likely to be impacted by water deficits that affect the nutrient uptake and production of secondary metabolites based on their timing and intensity. The aim of this study was to assess the effects of the water deficit on the nutritional quality of forage sorghum (Sorghum bicolor) hybrids. For that purpose, a factorial, completely randomized experiment was conducted by considering three forage sorghum hybrids (AGRI 002-E, BREVANT SS318, and BRS 658) and two levels of evapotranspiration water replacement (50% and 100% of ETc). Parameters relating to water consumption, secondary metabolites (isoflavones daidzein, daidzin, genistein, and genistin), leaf nutrients (P, K, Ca, Mg, S, Mn, and Zn), and bromatological attributes (dry matter, crude protein, neutral detergent fiber, and mineral material) were evaluated at the end of the crop cycle. Isoflavone levels differed between the hybrids and were highest in water-deficient sorghum. There was a significant interaction between the factors only for the daidzin. The leaf content of the other compounds was influenced either by hybrids (genistein) or by the replacement of evapotranspired water levels (daidzein). The leaf content of P and S was influenced by the interaction between the factors, while the levels of K, Ca, and Mg were influenced by the effect of a single factor. The leaf contents of Mn and Zn were not influenced by the treatments. There was a difference between the hybrids for dry mass and crude protein contents, and hybrids x water deficit was only significant for dry mass. The hybrids Brevant SS318 and BRS 658 had the highest crude protein. The presented results are novel and demonstrate that water deficits can significantly affect the levels of secondary metabolites and the nutritional quality of forage sorghum, depending on the hybrid. The mentioned indices are important parameters for evaluating the nutritional quality and development of agricultural crops, particularly in response to adverse environmental conditions such as water stress. [ABSTRACT FROM AUTHOR]

We studied the recovery of the growth and physiological parameters of Scots pine seedlings after long-term zinc toxicity. The removal of excess zinc from the nutrient solution resulted in the rapid recovery of primary root growth but did not promote the initiation and growth of lateral roots. The recovery of root growth was accompanied by the rapid uptake of manganese, magnesium, and copper. Despite the maximum rate of manganese uptake by the roots, the manganese content in the needles of the recovering plants did not reach control values during the 28 days of the experiment, unlike magnesium, iron, and copper. In general, the recovery of ion homeostasis eliminated all of the negative effects on the photosynthetic pigment content in the needles. However, these changes, along with recovery of the water content in the needles, were not accompanied by an increase in the weight gain of the recovering seedlings compared with that of the Zn-stressed seedlings. The increased accumulation of phenolic compounds in the needles persisted for a long period after excess zinc was removed from the nutrient solution. The decreased lignin content in the roots and needles is a characteristic feature of Zn-stressed plants. Moreover, the removal of excess zinc from the nutrient solution did not lead to an increase in the lignin content in the organs. [ABSTRACT FROM AUTHOR]

To assess the effect of pure castor meal and a mixture of castor meal with ground hydrothermalized phonolite rock (CM+HP mixture) in providing nutrients, particularly N and K, and optimizing yield and quality of sweet potato, a field experiment was conducted using a randomized block design. Treatments were the absence and presence of synthetic N and K fertilizers (ammonium nitrate and KCl) combined with rates of organic fertilizers (1.2 and 2.4 Mg ha−1 of castor meal, 2.25 and 4.5 Mg ha−1 of CM+HP mixture, plus a treatment without organic fertilizers). The CM+HP mixture maintained adequate N and K status in plant leaves. Organic fertilizers increased the number of storage roots per plant and the sweetness of the storage roots, while synthetic fertilizers increased the storage root mean weight. Castor meal combined with synthetic fertilizers improved soil health (increased organic matter and enzyme activity in the soil). The combined application of synthetic fertilizers with 2.4 Mg ha−1 of castor meal or 4.5 Mg ha−1 of CM+HP mixture had the greatest benefit on storage root yield, with an average increase of 128% (10.9 Mg ha−1) on marketable storage root yield, and the nutrient removal compared with the sole application of organic fertilizers. [ABSTRACT FROM AUTHOR]

Yerba mate is a forest species of both cultural and economic importance growing in the subtropical regions of South America, especially in the south of Brazil. Despite its importance, yerba mate has never received enough attention from researchers, so the nutritional sufficiency ranges and critical levels have not yet been determined. This research aimed to establish these parameters for yerba mate to enable its foliar diagnosis. A total of 167 leaf samples were collected from production fields located in the five yerba mate-growing regions in Rio Grande do Sul, and the leaf nutrients were determined by standard chemical methods. The yield of each production field was accessed, and the cutoff value separating low- and high-yield groups was calculated in 16.75 Mg ha−1. The multivariate compositional nutrient diagnosis (CND) standards were determined, and nutrient interactions were estimated by correlation and principal component analyses. There was no positive correlation between any single nutrient and yield, even in the high-yield population, evidencing that a higher yield is the outcome of the balance among all nutrients. Excess of B occurred in one-third of the low-yield samples, while deficiency of Cu and K occurred in one-fourth of these samples. Finally, we established the adequate leaf nutrient levels for yerba mate. [ABSTRACT FROM AUTHOR]

An experiment was conducted with two-year-old 'Fino 95' lemon plants (Citrus limon Burm. f. cv. Fino) grafted on C. macrophylla (Citrus macrophylla Wester) to study the effects of salinity on plants inoculated with arbuscular mycorrhizal fungi (AMF). Half of the inoculated (+AM) and non-inoculated (−AM) plants were irrigated with half-strength Hoagland solution, and the remainder were inoculated with half-strength Hoagland solution + 30 mM NaCl. Ninety-eight days later, results showed that AMF had alleviated the negative effect of salinity on growth. Inoculation with AMF provided some protection against the damage that salinity caused on cellular membranes and improved the plant water status and turgor under saline conditions (Ψx and Π increased by 16% and 48%, respectively). The responses of mineral nutrition to salinity and AMF treatments were complex. P concentrations in the leaves and roots of +AM plants were lower than in those of −AM plants, but inoculation improved Ca2+ (by 20%), Mg2+ (24%), Fe2+ (21%), and Zn2+ (7%) nutrition in roots and also the Mg2+/Na+ ratio in leaves (33%), reducing the antagonistic effect of Na+ on Mg2+ nutrition in salt-treated plants. AMF could protect plants against salt stress through the maintenance of the gas exchange capacity and due to a better antioxidant response. All these positive effects of AMF contributed to mitigating the harmful effects of salinity stress on the plant growth performance of lemon trees grafted on C. macrophylla rootstock under salinity conditions. [ABSTRACT FROM AUTHOR]

Simple Summary: Understanding placental vascularity is vital for ensuring the proper nourishment of the fetus and, therefore, a healthy offspring. We aimed to investigate the impact of vitamin and mineral supplementation and/or different rates of body weight gain on placental vascularity in beef heifers. To this end, in the first experiment, heifers were divided into groups that received vitamin and mineral supplementation or did not at least 72 days before breeding. At breeding, they were further divided into low or moderate-weight gain groups, resulting in four different treatments maintained until day 83 of pregnancy when tissue collection was performed. In the second experiment, another group of heifers received a basal diet or a diet with vitamin and mineral supplementation from breeding until parturition. We evaluated placental blood vessel density in both experiments and the placental expression of genes related to blood vessel growth in the first experiment. Results showed that supplementation and the rate of body weight gain during early pregnancy did not significantly affect placental vascularity or the expression of angiogenic factors. On the other hand, placental vascularity measured at parturition was increased in the fetal placenta of the supplemented group. These findings suggest that supplementation with vitamins and minerals throughout all gestation may impact placental function at a later stage of pregnancy. The effect of vitamins and minerals supplementation (VTM) and/or two rates of body weight gain (GAIN) on bovine placental vascular development and angiogenic factors gene expression were evaluated in two experiments: In Exp. 1, crossbred Angus heifers (n = 34) were assigned to VTM/NoVTM treatments at least 71 days before breeding to allow changes in the mineral status. At breeding, through artificial insemination (AI), heifers were assigned to low-gain (LG) 0.28 kg/d or moderate-gain (MG) 0.79 kg/d treatments, resulting in NoVTM-LG (Control; n = 8), NoVTM-MG (n = 8), VTM-LG (n = 9), and VTM-MG (n = 9) until day 83 of gestation; In Exp. 2, crossbred angus heifers (n = 28), were assigned to control (CON; n = 12), receiving a basal total mixed ration (TMR) or TMR + VTM (VTM; n = 16) from breeding until parturition. Placentomes from Exp. 1 and cotyledons (COT) from Exp. 2 were evaluated by immunohistochemistry for COT vascular density area. COTs from Exp. 1 were evaluated for angiogenic factor (ANGPT-1, ANGPT-2, eNOS2, eNOS3, FLT1, KDR, TEK, VEGFA) gene expression. In Exp. 1, COT vascularity was not affected by the interaction of VTM and GAIN (p = 0.67) or the main effects of VTM (p = 0.50) and GAIN (p = 0.55). Likewise, angiogenic factors were not differentially expressed between treatments (p < 0.05). In Exp. 2, COT vascularity was greater in VTM vs. CON (p = 0.07). In conclusion, there is a suggested later-stage influence of vitamin and mineral supplementation on placental vascularity, emphasizing the importance of supplementation beyond early pregnancy. [ABSTRACT FROM AUTHOR]

Mesembryanthemum crystallinum L. is an obligatory halophyte species showing optimum growth at elevated soil salinity levels, but the ionic requirements for growth stimulation are not known. The aim of the present study was to compare the effects of sodium, potassium and calcium in the form of chloride and nitrate salts on the growth, physiological performance, ion accumulation and mineral nutrition of M. crystallinum plants in controlled conditions. In a paradoxical way, while sodium and potassium had comparable stimulative effect on plant growth, the effect of calcium was strongly negative even at a relatively low concentration, eventually leading to plant death. Moreover, the effect of Ca nitrate was less negative in comparison to that of Ca chloride, but K in the form of nitrate had some negative effects. There were three components of the stimulation of biomass accumulation by NaCl and KCl salinity in M. crsytallinum: the increase in tissue water content, increase in ion accumulation, and growth activation. As optimum growth was in a salinity range from 20 to 100 mM, the increase in the dry biomass of plants at a moderate (200 mM) and high (400 mM) salinity in comparison to control plants was mostly due to ion accumulation. Among physiological indicators, changes in leaf chlorophyll concentration appeared relatively late, but the chlorophyll a fluorescence parameter, Performance Index Total, was the most sensitive to the effect of salts. In conclusion, both sodium and potassium in the form of chloride salts are efficient in promoting the optimum growth of M. crystallinum plants. However, mechanisms leading to the negative effect of calcium on plants need to be assessed further. [ABSTRACT FROM AUTHOR]

Nutrients and light are critical factors for sustained Centella asiatica L. Urban production under a controlled environment. The growth, triterpene glycosides, and antioxidant activities of C. asiatica grown under a controlled environment with different nutrient solution formulations (NFFs) and LED light intensities were investigated. Four different NSFs were tested on plant growth, bioactive compounds, and their activities in a conventional greenhouse. The results showed that the plants grown with Houghland and Arnon solution exhibited better growth performance, whereas the use of Resh's Tropical Dry Summer solution led to increased bioactive compounds and their activities. Subsequently, Resh's Tropical Dry Summer solution was selected to evaluate the effect of light intensity in a controlled environment. Plants were grown under three LED light intensities (110, 220, and 330 µmol/m2/s PPFD) compared with fluorescent and natural lights (45 and 326 µmol/m2/s PPFD, respectively). We found that light intensity had the strongest influence on growth, triterpene glycosides, and antioxidant activities. Significantly higher values of the most studied parameters were observed in plants grown under high light intensity compared to those grown under low light intensity. The optimal light intensity was 330 µmol/m2/s PPFD, representing an efficient approach for commercially producing this medicinal plant with a higher yield and medicinal properties in a controlled environment. [ABSTRACT FROM AUTHOR]

Utilizing water resources rationally has become critical due to the expected increase in water scarcity. Cacti are capable of surviving with minimal water requirements and in poor soils. Despite being highly drought-resistant, cacti still faces limitations in realizing its full potential under drought-stress conditions. To this end, we investigated the interactive effect of humic substances (Hs) and arbuscular mycorrhizal fungi (AMF) on cactus plants under drought stress. In the study, a cactus pot experiment had three irrigation levels (W1: no irrigation, W2: 15% of field capacity, and W3: 30% of field capacity) and two biostimulants (Hs soil amendment and AMF inoculation), applied alone or combined. The findings show that the W1 and W2 regimes affected cactus performance. However, Hs and/or AMF significantly improved growth. Our results revealed that drought increased the generation of reactive oxygen species. However, Hs and/or AMF application improved nutrient uptake and increased anthocyanin content and free amino acids. Furthermore, the soil's organic matter, phosphorus, nitrogen, and potassium contents were improved by the application of these biostimulants. Altogether, using Hs alone or in combination with AMF can be an effective and sustainable approach to enhance the tolerance of cactus plants to drought conditions, while also improving the soil quality. [ABSTRACT FROM AUTHOR]

(1) Background: This study investigates the effects of potassium (K) and rootstock on the growth, photosynthetic activity, and mineral nutrition of lemon trees; (2) Methods: Lemon trees (cv. Adamopoulou) grafted onto sour orange (Citrus aurantium) (SO) or Volkamer lemon (Citrus volkameriana) (VL) rootstock were cultivated hydroponically under 0.00, 0.75, 1.50, 3.00, and 6.00 mM K. Plant growth and nutrition parameters, as well as leaf photosynthetic rate, stomatal conductance, transpiration rate, intracellular CO2, chlorophyll, and carotenoid concentration were assessed; (3) Results: Under K deficiency (0 mM K), plants exhibited chlorotic and necrotic symptoms, more pronounced in older leaves. Potassium deficiency adversely affected various physiological processes in lemon leaves, including a decrease in photosynthesis rate, stomatal conductance, transpiration rate, intercellular CO2 concentration, water use efficiency, CO2 utilization efficiency, chlorophyll a/b ratio, and carotenoid concentrations (some effects were rootstock-dependent). Low photosynthetic rates under K deficiency were due to both stomatal- and non-stomatal limitations. Elevated K in the nutrient solution consistently reduced the total plant uptake of P, Ca, Mg, B, Mn, and Zn, resulting in nutrient imbalances, as evidenced by the significant decrease in P, Ca, Mg, and Zn concentrations found in scion tissues (especially at the 6 mM K treatment). Rootstock-dependent responses were also observed in scion leaf and stem growth and in mineral nutrient concentrations, uptake, and distribution across plant parts; (4) Conclusions: Our study reveals interesting aspects on how to optimize K fertilization in lemon trees in the context of sustainable agriculture by considering nutrient interactions and rootstock-dependent effects. Understanding these complex interactions and improving K fertilization practices is expected to improve lemon tree performance, yield, and fruit quality. [ABSTRACT FROM AUTHOR]

The overuse of chemical pesticides and fertilizers in crop farming has led to a decrease in crop quality and negative impacts on soil and the environment. It is crucial to adopt alternative strategies to maintain soil and environmental quality while enhancing crop growth and yield. To explore this, a study was conducted under greenhouse conditions to investigate the effect of Rhizobium tropici CIAT 899 alone, as well as in association with mycorrhizae (Rhizophagus irregularis) and endophytic fungus (Serendipita indica), on the growth, yield, and nutrient status of snap bean plants. At harvest, the rhizobial strain CIAT 899 demonstrated the highest effectiveness. It significantly increased the number of nodules in both Contender and Garrafal Enana varieties by 6.97% and 14.81%, respectively, compared with the control without inoculation. Furthermore, the results indicated that co-inoculation of Rhizobium and symbiotic fungi had positive effects on nitrogen content, phosphorus availability, and overall plant growth. Regardless of the variety, plants inoculated with R. tropici CIAT 899 and Serendipita indica exhibited the highest values for plant growth parameters. This combination resulted in 168% and 135% increases in root dry biomass, as well as 140% and 225% increases in the number of pods for Contender and Garrafal Enana, respectively, compared with the control at harvest. Additionally, this study highlights the potential benefits of combining R. tropici with either Serendipita indica or Rhizophagus irregularis in terms of nitrogen and phosphorus uptake. These symbiotic microorganisms demonstrated synergistic interactions with snap bean plants, leading to improved mineral nutrition and enhanced growth. Overall, these findings suggest that utilizing these symbiotic microorganisms can effectively enhance the mineral nutrition and growth of snap bean plants. [ABSTRACT FROM AUTHOR]

In semiarid regions of Brazil, water and/or soil salinity is one of the limiting factors for sour passion fruit production. Low rainfall rates combined with edaphic conditions (high concentrations of soluble salts) intensify deleterious effects on plants. Thus, strategies that minimize the effects of salt stress, e.g., grafting with tolerant species and soil mulching, are extremely important to ensure the expansion of irrigated fruit farming in this region. From this perspective, this study aimed to evaluate the effect of grafting and mulching on the quantum yield, ionic relations, and fruit production of sour passion fruit irrigated with moderately saline water. The experiment was conducted under field conditions in split plots, in a 2 × (2 × 2) factorial arrangement to evaluate the combination of low and moderate salinity water (main plot) with the propagation method (seeds and grafting on P. cincinnata) and without and with plastic mulching (subplots), with four replications and three plants per plot. The ionic relations in passion fruit leaves were increased with the use of rootstocks and plastic mulching under irrigation with moderately saline water. The use of mulching increased the yield of photosystem II in sour passion fruit. The passion fruit plants propagated by seeds had 187.52% more fruits than those grafted onto P. cincinnata. The use of rootstocks with P. cincinnata in sour passion fruit restricted the uptake of Na and Cl but reduced fruit production. [ABSTRACT FROM AUTHOR]

The precise management of the nutrient solution pH is substantial for optimizing the growth and yield of hydroponically cultivated crops. Nutrient solution pH affects the solubility and availability of essential nutrients; however, during hydroponic cultivation, the pH of nutrient solution fluctuates due to unbalanced ion absorption by plants. Nutrient solution pH fluctuations might be passively controlled using a supplementary buffering agent. Nutrient solution characteristics such as pH and buffering agent molarity must be addressed simultaneously. Therefore, in this study, we aimed to evaluate hydroponically cultivated lettuce's physiological response to minor nutrient solution pH differences and the impact of supplementary buffering agent molarity on its growth, antioxidant activity, and mineral nutrient uptake. Green lettuce (Lactuca sativa (L.)) 'Hugin' was cultivated in deep water culture (DWC) hydroponics in a controlled environment replicating common vertical farming conditions, and nutrient solution pH impact within the range of 5.0–6.5 was evaluated every 0.5 pH unit. Initial nutrient solution buffer capacity was enhanced by adding MES (2-(N-morpholino) ethanesulfonic acid) at 0, 1, 3, and 5 mM concentrations. Results show that even small nutrient pH differences are reflected in plant physiological responses, indicating the significance of precise pH management. Even though dry weight accumulation is not affected by the pH 5.0–5.5 treatment, it increases root antioxidant response according to ABTS (2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activity. An initial nutrient solution buffer capacity increment with 3 mM of MES (2-(N-morpholino) ethanesulfonic acid) supplementary buffering agent resulted in a 17% yield increase compared to a nutrient solution without an additional buffering agent. MES buffer can provide adequate, passive, and precise nutrient solution pH control within the pH range of 6.0–6.5. [ABSTRACT FROM AUTHOR]

Heavy metals (HMs) contamination is one of the main abiotic factors affecting crop productivity and also threatens human health via consuming metal-contaminated crops as a food source. Over the past few years, HMs have drawn a lot of attention due to their increased use for commercial purposes and their harmful effects on plants and other life forms, thus threatening human survival. However, several methods have been adopted in recent years to combat the harsh effects of HMs. After phytohormones, the use of mineral nutrients such as selenium (Se) in the prevention of HM stress has been explored by researchers more recently. Selenium is an important micronutrient widely known for its antioxidant properties in plants and animals. Exogenous Se inhibits metal uptake and translocation and improves the antioxidant system, thus imparting resistance to HM toxicity in plants. Moreover, Se also regulates the production of various osmolytes in cells, which helps develop cell osmolarity. Selenium also produces different secondary metabolites in plants' defense mechanisms against different stresses. The uptake of mineral nutrients is a vital process for plant growth and development, which is also positively correlated with Se under metalloid toxicity. However, to understand the exact mechanism of Se in HM tolerance, different metabolic processes stimulated by Se and their pathways need to be explored. Hence, this review focuses on the role of Se on nutritional status, antioxidant metabolism, interaction with phytohormones and its role in the regulation of various genes involved in Se-induced HM tolerance. Thus, this study will help researchers in the future for the improvement of HM tolerance via Se application in plants. [ABSTRACT FROM AUTHOR]

Genetic characteristics and their interaction with environmental conditions, including nutritional management, determine coffee productivity and quality. The objective of this study was to evaluate fruit traits and nutrient accumulation in the fruit, husk, and bean, as well as in the leaves of different Coffea arabica cultivars cropped in the Gorongosa National Park, Mozambique. The experiment evaluated nine coffee cultivars in a randomized block design, with four replicates. Fruit and leaf samples were collected over two months (June and July 2021), in the fruit maturation phase, oven-dried and analyzed, namely, through a clustering unweighted pair group method with arithmetic mean (UPGMA). The characterization of ripe and dried coffee bean indicated differences in the performance of the cultivars. The accumulation of the macronutrients N, K, and Ca and micronutrients Fe, Mn, and B was highest in the bean, husk, fruit, and leaves of the evaluated cultivars. Nutrient concentrations and accumulation in the different evaluated organs have a direct influence on the nutritional crop management. This is crucial for a nutritional diagnosis that ensures high yields, but such mineral levels are also a result of the existing genetic diversity among cultivars, which must be taken into account for management and breeding purposes. [ABSTRACT FROM AUTHOR]

Glyphosate-resistant (GR) maize is dominant in countries where it is grown. Significant, adverse effects of glyphosate application to GR maize have been reported, but few data from robust studies exist to determine if such effects are common. In this study, the effects of recommended application rates (single and sequential applications) were used on GR maize grown at two locations for one season and for two seasons in a third location. No significant effects of glyphosate on mineral content (N, P, K, Ca, Mg, S, Cu, Fe, Mn, and Zn) in leaves or grain, plant height, stem diameter, ear parameters, or yield were found at any location or in any growing season. Likewise, harvested grain quality, as determined by percent starch, protein, and total lipids, was unaffected by glyphosate treatment at any location. Neither glyphosate nor aminomethylphosphonic acid, the primary degradation product of glyphosate, were found in grain from any treatment at any location, except for 20 ng g−1 of glyphosate found in grain from one season at one location. These results support the view that recommended applications of glyphosate have no significant effects on growth, grain composition, mineral content, grain quality, nor yield of GR maize. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) are widely present in heavy metal-polluted soils, but their effects on straw degradation and plant growth of rotated crops are poorly understood. In this study, a pot experiment was used to simulate the return of fore-rotating crop (Brassica napus L.) straw to farmland with a subsequent planting of maize in a lead–zinc mining area on the Yunnan Plateau, Southwest China, which included four treatments: control (CK), addition of rape straw (SR), inoculation of AMF (AMF), and both AMF inoculation and straw addition (AMF + SR). The effects of AMF on the degradation and nutrient release of the fore-rotating rape straw and the growth, mineral nutrition and the cadmium (Cd) and lead (Pb) contents of the subsequent maize were investigated. Compared with the CK treatment, AMF significantly promoted the degradation of rape straw and the release of mineral nutrients (nitrogen, phosphorus and potassium) as well as the Cd and Pb, increased the content of available nutrients in soil, and improved the mineral nutrient contents in the maize. AMF + SR significantly increased the maize height and biomass by 32–35% and decreased the available Cd and Pb contents in soil and the Cd and Pb contents in the maize by 20–30% and 18–25%, respectively. Moreover, the available Cd and Pb contents in the soil presented significant positive correlations with their contents in the maize but negative correlations with the height and biomass of the maize. Thus, AMF played an important regulatory role in the nutrient cycling and heavy metal accumulation of the crop rotation. [ABSTRACT FROM AUTHOR]

Phenolic compounds and glucosinolates are secondary plant metabolites that play fundamental roles in plant resistance to abiotic stress. These compounds have been found to increase in stress situations related to plant adaptive capacity. This review assesses the functions of phenolic compounds and glucosinolates in plant interactions involving abiotic stresses such as drought, salinity, high temperature, metals toxicity, and mineral deficiency or excess. Furthermore, their relation with water uptake and transport mediated through aquaporins is reviewed. In this way, the increases of phenolic compounds and glucosinolate synthesis have been related to primary responses to abiotic stress and induction of resistance. Thus, their metabolic pathways, root exudation, and external application are related to internal cell and tissue movement, with a lack of information in this latter aspect. [ABSTRACT FROM AUTHOR]

In the Ericaceae family, blueberries are the most commercially important species. Estimating the nutritional and physiological status of plants is a common practice carried out by producers. However, conventional methods are destructive, costly and time consuming. In recent years, methodologies such as measurements with the SPAD chlorophyll index have become available, which has proven to be an easy, fast and non-destructive method for estimating chlorophyll, N and Mg contents in the field. Therefore, this research aimed to estimate variations in SPAD readings between varieties and to determine whether Chlorophyll Index (SPAD) values are associated with Nitrogen and Magnesium contents in blueberry plants (Vaccinium corymbosum L.) from the varieties 'Biloxi', 'Legacy' and 'Victoria' in the vegetative phase under the conditions in the municipality of Paipa-Boyacá (Colombia). The varieties presented statistical differences in the SPAD index values, with a linear correlation between the SPAD index and the contents of N and Mg with a coefficient of determination (R2) greater than 0.8 in the three varieties. This result confirmed the usefulness and importance of using SPAD as a nutrition management tool in the evaluated varieties based on the SPAD readings, with a subsequent relationship with the threshold values of the foliar N and Magnesium status under field conditions. [ABSTRACT FROM AUTHOR]

Potassium (K) is an essential element, which is often supplied to horticultural crops via foliar spraying. Some studies have investigated the effect of different foliar-applied K compounds; however, most studies have focussed on crop quality and yield parameters, or were performed with isolated leaf cuticles. The aim of this study was to evaluate the rates of the foliar ion penetration and leaf surface deposition of 130 mM K sprays of compounds with markedly different point of deliquescence (POD) and efflorescence (POE) values, the rates having been previously estimated in climate chamber trials. Shoots of field-grown, commercial olive trees were sprayed with K-nitrate (KNO3), K-sulphate (K2SO4), K-chloride (KCl), K-phosphate (K3PO4), K-carbonate (K2CO3) and K-bicarbonate (KHCO3), and leaf samples were collected after 3 and 24 h. Cation and anion concentrations were determined in the leaf tissues, and in a preliminary leaf water wash for estimating surface-deposited ion concentrations. No significant leaf tissue K increments were recorded between the K sprays. Olive tissue anion concentrations showed different patterns, and a chloride (Cl−) increase was detected 3 h after the foliar KCl supply. On the other hand, the foliar K applications led to leaf nitrate changes regardless of the K source supplied. High amounts of K and accompanying ions were recovered in the washing liquid of the foliar K-supplied leaves. Some foliar K treatments increased the leaf surface concentration of sulphate and chloride, suggesting a potential effect on leaf cell anion extrusion. Hence, despite no evidence of foliar K uptake, an effect of leaf anion concentrations was observed, indicating that foliar nutrient sprays may influence leaf and leaf surface anion balance. [ABSTRACT FROM AUTHOR]

In recent decades, forest nurseries in eastern Canada have been faced with periods of mild winter weather, delayed snowfall, and low seedling protective snow cover combined with winter rains instead of snowfall. These extreme conditions have resulted in the loss of millions of seedlings, in particular those that overwinter outdoors, probably due to their winter dehardening. The main objective of this study is to simulate different periods of warm weather at the beginning and end of winter and evaluate their effects on the dehardening and growth of Picea mariana and Picea glauca seedlings in response to different freezing temperatures. Three warming treatments were simulated (control, 1 day, and 3 days of warming at 10 °C) followed by three freezing temperatures (−4, −12, and −20 °C). In winter, regardless of the warming treatment, the seedlings of the two species tolerated the different freezing temperatures without any apparent damage. However, at the end of winter and in the absence of snow cover, the seedlings did not show frost tolerance at −20 °C. On the other hand, the seedlings showed normal growth after undergoing frosts at −4 °C and −12 °C, similar to that observed for control seedlings. Different cultural practices and protection strategies are proposed to improve frost tolerance and reduce the winter loss of seedlings. [ABSTRACT FROM AUTHOR]

Clonal Eucalyptus propagation is essential for various industry sectors. It requires cuttings to successfully develop adventitious roots (ARs). Environmental conditions are influential on AR development and may be altered to modulate the productivity of hard-to-root clones. The current knowledge gap in research on the physiological patterns underlying commercial-scale propagation results hinders the design of novel strategies. This study aimed to identify patterns of variation in AR-relevant parameters in contrasting seasons and species with distinct rooting performances. E. dunnii and E. ×urograndis (hard- (hardR) and easy-to-root (easyR), respectively) mini-stumps were subjected to light modulation treatments and to mini-tunnel use (MT) for a year. The treatment impact on the branching and rooting rates was recorded. The carbohydrate content, AR-related gene expression, and mineral nutrition profiles of cuttings from the control (Ctrl) and treated mini-stumps were analyzed. Light treatments were often detrimental to overall productivity, while MTs had a positive effect during summer, when it altered the cutting leaf nutrient profiles. Species and seasonality played large roles in all the assessed parameters. E. ×urograndis was particularly susceptible to seasonality, and its overall superior performance correlated with changes in its gene expression profile from excision to AR formation. These patterns indicate fundamental differences between easyR and hardR clones that contribute to the design of data-driven management strategies aiming to enhance propagation protocols. [ABSTRACT FROM AUTHOR]

Lettuce is widely used for its healthy properties, and it is of interest to increase them with minimal environmental impact. The purpose of this work was to evaluate the effect of the arbuscular mycorrhizal fungus (AMF) Funneliformis mosseae in lettuce plants (Lactuca sativa L. cv. Salinas) cultivated in a soilless system with sub-optimal phosphorus (P) compared with non-inoculated controls at two different P concentrations. Results show that lettuce inoculation with the selected AMF can improve the growth and the nutritional quality of lettuce even at sub-optimal P. Leaf content of chlorophylls, carotenoids, and phenols, known as important bioactive compounds for human health, was higher in mycorrhizal lettuce plants compared with non-mycorrhizal plants. The antioxidant capacity in AMF plants showed higher values compared with control plants grown at optimal P nutrition level. Moreover, leaf gas exchanges were higher in inoculated plants than in non-inoculated ones. Nitrogen, P, and magnesium leaf content was significantly higher in mycorrhizal plants compared with non-mycorrhizal plants grown with the same P level. These findings suggest that F. mosseae can stimulate plants growth, improving the nutritional quality of lettuce leaves even when grown with sub-optimal P concentration. [ABSTRACT FROM AUTHOR]

Salt stress during pre-harvest limits the shelf life and post-harvest quality of produce; however, silicon nutrition can mitigate salt stress in plants. Thus, we evaluated the effects of salinity and fertilization with Si, in pre-harvest, on the morpho-physiological characteristics of onion bulbs during shelf life. The experiment was set up in randomized complete blocks, with treatments arranged in split-split plots. The plots had four levels of electrical conductivity of irrigation water (0.65, 1.7, 2.8, and 4.1 dS m−1). The subplots had five fertilization levels with Si (0, 41.6, 83.2, 124.8, and 166.4 kg ha−1). The sub-sub plots had four shelf times (0, 20, 40, and 60 days after harvest). Irrigation water salinity and shelf time reduced firmness and increased the mass loss of onion bulbs during shelf life. Salt stress reduced the contents of sugars and total soluble solids of onion bulbs during storage; however, Si supply improved the contents of these variables. Salinity, Si supply, and shelf time increased the concentrations of pyruvic and ascorbic acids in onion bulbs during shelf life. Si doses between 121.8 and 127.0 kg ha−1 attenuated the impacts caused by moderate salinity, increasing the synthesis of metabolites and prolonging the onion bulbs' shelf life. [ABSTRACT FROM AUTHOR]

The agronomic biofortification of vegetables is a strategy for increasing the concentration of iron (Fe) in food and, consequently, the intake of this micronutrient by the population. When in deficiency, it can cause anemia—a pathology that affects millions of people. Soil-less cultivation is an important cropping system, but there are no studies on how Fe concentrations in a nutrient solution can promote biofortification and affect the quality of collard greens; this is the aim of the present study. For this purpose, five Fe concentrations (2, 4, 6, 8 and 10 mg L−1) were evaluated. Increasing the Fe concentration in the nutrient solution increased the leaf Fe content and decreased the leaf contents of cationic nutrients, without affecting yield. Photosynthetic pigment contents were positively affected by Fe concentrations, while ascorbic acid decreased. There was efficient biofortification of collard greens leaves from 4 mg L−1 Fe, and a higher nutritional quality of leaves was observed at Fe concentrations of 8 mg L−1. [ABSTRACT FROM AUTHOR]

Oak forests are facing multiple threats due to global change, with the introduction and expansion of invasive pathogens as one of the most detrimental. Here, we evaluated the use of soil biological fertiliser Biohumin® to improve the response of Quercus ilex L. to the soil-borne pathogen Phytophthora cinnamomi Rands by using one-year-old seedlings fertilised at 0, 12.5, and 25% concentrations of Biohumin® (v/v). Our hypothesis was that plant vigour and response to the pathogen would improve with Biohumin®. The effects of soil infestation and fertilisation were tested by assessing plant survival, growth, and physiology. The soil infested with P. cinnamomi negatively affected all the studied traits. We observed that a moderate concentration of Biohumin® (12.5%) increased plant survival. However, a high concentration (25%) reduced the survival compared with the control, probably as a result of the stress caused by both biotic (infection) and abiotic (soil toxicity) factors. Biohumin® at the highest concentration reduced the plant height-to-stem diameter ratio (H/D) and negatively affected plant biomass and physiological activity. Combined biofertilisation and infection induced synergistic negative effects in the leaf water potential compared with infection and fertilisation applied alone. A higher concentration of Biohumin® may favour pathogens more than plants. Further studies should explore the causes of the negative effect of the high concentration of Biohumin® observed here and evaluate if lower concentrations may benefit plant survival and physiology against soil pathogens. [ABSTRACT FROM AUTHOR]

The deterioration of plant mineral nutrition during drought is a significant factor in the negative influence of drought on plant performance. We aimed to study the effects of seasonal and multiyear water shortages on nutrient supply and demand in Scots pine and Norway spruce. We studied pine and spruce trees naturally grown in the Bryansk region (Russia). The dynamics of several nutrients (K, Ca, Mg, P, Fe, Mn, Zn, and Ca) in wood, needles, and bark of current-year twigs and the dynamics of the available pools of these elements at different soil depths were analysed. To assess the physiological consequences of changes in element concentrations, lipid peroxidation products and photosynthetic pigments were measured in the needles. Water shortage increased the wood concentrations of all elements except for Mn. In pine, this increase was mainly due to seasonal water deficit, whereas in spruce, multiyear differences in water supply were more important. This increased availability of nutrients was not observed in soil-based analyses. In needles, quite similar patterns of changes were found between species, with Mg increasing almost twofold and Fe and Mn decreasing under water shortage, whereas the remainder of the elements did not change much under differing water supplies. Neither the concentrations of photosynthetic pigments nor the contents of lipid peroxidation products correlated with element dynamics in needles. In summary, water shortage increased the availability of all elements except Mn for the plant; however, needle element contents were regulated independently of element availability for plants. [ABSTRACT FROM AUTHOR]

The aim of this study was to establish DRIS (Diagnosis and Recommendation Integrated System) norms and Nutritional Optimal Ranges (NOR) for 'Rojo Brillante' Protected Designation of Origin (PDO) 'Ribera del Xúquer'. The database contained 800 leaf samples collected in different crop phenological stages [after flowering (AF), fruit enlargement (FE), fruit colouring (FC), and harvesting HV)]. DRIS norms (78) were established for macronutrients: N, P, K, Ca, Mg and S; micronutrients B, Cu, Fe, Mn, and Zn and salinity elements: Na and Cl. The Nutrient Balance Index (NBI; the absolute value of the sum of the DRIS indices) was used to determine the optimal sampling period. Fruit enlargement was the period during which persimmon trees were more nutritionally balanced regardless of sprout origin (vegetative or floral) and irrigation type (drip or flood) in orchards [ABSTRACT FROM AUTHOR]

The design of an adequate culture medium is an essential step in the micropropagation process of plant species. Adjustment and balance of medium components involve the interaction of several factors, such as mineral nutrients, vitamins, and plant growth regulators (PGRs). This work aimed to shed light on the role of these three components on the plant growth and quality of micropropagated woody plants, using Actinidia arguta as a plant model. Two experiments using a five-dimensional experimental design space were defined using the Design of Experiments (DoE) method, to study the effect of five mineral factors (NH4NO3, KNO3, Mesos, Micros, and Iron) and five vitamins (Myo-inositol, thiamine, nicotinic acid, pyridoxine, and vitamin E). A third experiment, using 20 combinations of two PGRs: BAP (6-benzylaminopurine) and GA3 (gibberellic acid) was performed. Artificial Neural Networks (ANNs) algorithms were used to build models with the whole database to determine the effect of those components on several growth and quality parameters. Neurofuzzy logic allowed us to decipher and generate new knowledge on the hierarchy of some minerals as essential components of the culture media over vitamins and PRGs, suggesting rules about how MS basal media formulation could be modified to assess the quality of micropropagated woody plants. [ABSTRACT FROM AUTHOR]

Lettuce is an important vegetable cultivated worldwide, even in regions with highly saline soils. A large amount of research discusses the application of sulfur on the increase of antioxidation in plants. The powder from hoggery desulfurization tanks contained high amounts of sulfur and small amounts of other nutrients for plants. This powder can be added to liquid fertilizer to create high-sulfur liquid fertilizer (HSLF). This study observed the cell morphologies of lettuce root apices under salt stress after the application of HSLF. Lettuce plants were cultivated in hydroponic solutions containing one of two NaCl (0 and 40 mM) and three HSLF (0.0, 1.5, and 3.0 g L−1) concentrations. Salinity reduced the K+/Na+ ratio in the plant leaves; however, this reduction was smaller in the HSLF-treated plants. Except for phosphate and potassium, nutrient absorption is inhibited under conditions of high salinity. Using scanning electron microscopy, we observed apices more integrated on cell roots after increasing HSLF supplement under non-salt-stressed conditions. In addition, the cells were repaired after increasing the supplement of HSLF under the condition of 40 mM NaCl. Although salt stress reduced plant growth, the reductions were minimized in the HSLF-treated plants. The application of HSLF potentially alleviated salt injury in lettuce root apices and was probably associated with the improvement of phosphorus and potassium absorption and increasing K+/Na+ ratios in lettuce plants. [ABSTRACT FROM AUTHOR]

Crop wild relatives represent a valuable resource for the breeding of new crop varieties suitable for sustainable productivity in conditions of climate change. The aim of the present study was to assess salt tolerance of several wild accessions of T. fragiferum from habitats with different salinity levels in controlled conditions. Decrease of plant biomass and changes in partitioning between different organs was a characteristic response of plants with increasing substrate salinity, but these responses were genotype-specific. In several accessions, salinity stimulated reproductive development. The major differences in salinity responses between various T. fragiferum genotypes were at the level of dry biomass accumulation as well as water accumulation in plant tissues, resulting in relatively more similar effect on fresh mass. Na+ and Cl− accumulation capacity were organ-specific, with leaf petioles accumulating more, followed by leaf blades and stolons. Responses of mineral nutrition clearly were both genotype- and organ-specific, but several elements showed a relatively general pattern, such as increase in Zn concentration in all plant parts, and decrease in Ca and Mg concentration. Alterations in mineralome possibly reflect a reprogramming of the metabolism to adapt to changes in growth, morphology and ion accumulation resulting from effect of NaCl. High intraspecies morphological and physiological variability in responses of T. fragiferum accessions to salinity allow to describe them as ecotypes. [ABSTRACT FROM AUTHOR]

Nanoencapsulation with proteoliposomes from natural membranes has been proposed as a carrier for the highly efficient delivery of mineral nutrients into plant tissues. Since Boron deficiency occurred frequently in crops, and is an element with low movement in tissues, in this work, nanoencapsulated B vs free B was applied to in vitro sweet potato plants to investigate the regulation of B transporters (aquaporins and specific transporters). Additionally, an metabolomic analysis was performed, and mineral nutrient and pigment concentrations were determined. The results showed high increases in B concentration in leaves when B was applied as encapsulated, but also Fe and Mn concentration increased. Likewise, the metabolomics study showed that single carbohydrates of these plants could be related to the energy need for increasing the expression of most NIP aquaporins (NIP1;2, NIP1;3; NIP4;1, NIP4;2, NIP5;1, NIP6;1, and NIP7) and boron transporters (BOR2, BOR4 and BOR7;1). Therefore, the results were associated with the higher mobility of encapsulated B into leaves and the stimulation of transport into cells, since after applying encapsulated B, the aforementioned NIPs and BORs increased in expression. [ABSTRACT FROM AUTHOR]

The production and quality of grapes are determined by the hydric and nutritional status of the vine. In modern viticulture, the interface between grapevine and soil is represented by the rootstock, which modulates the uptake of water and nutrients. Thus, selection of new rootstocks for abiotic stress tolerance represents an adaptation strategy for viticulture to the new environmental conditions imposed by climate change. The aim of this work is to evaluate the water-use efficiency (WUE) and the nutritional status of a selection of 30 new rootstock genotypes, originating from several breeding programs. WUE and gas exchange were measured for each genotype in two environments characterized by different water availability, and the levels of N, P, K, Mg, Ca, Na, Fe, Mn, and Zn in the leaf blades were determined during the phenological stages of flowering and ripening. Water availability was different in the two environments, affecting gas exchange, with mean values of carbon assimilation of 10.43 ± 0.32 and 3.84 ± 0.34 µmol CO2 m−2 s−1, respectively. Genotypes were classified according to their water stress tolerance, vigor, and affinity for macronutrients and micronutrients. A total of 14 genotypes showed tolerance to water stress, and 10 of them reported high vigor and carbon assimilation. Furthermore, the majority of water-stress-tolerant genotypes had greater affinity for Mg than for K. In further studies, the most promising rootstocks will be evaluated in grafting combination with Vitis vinifera. [ABSTRACT FROM AUTHOR]

Growing Picea glauca seedlings poses many challenges for forest nursery managers, includ- ing reaching the target height at the end of the first growing season (1 + 0) and the homogeneity and uniformity of seedling growth. To increase growth and morphophysiological quality of white spruce seedlings (1 + 0), emphasis was placed on improving the physicochemistry of the acidic peat substrate by replacing silica with granular calcite as a covering material. The objective of our study is to compare the effects of silica and calcite on the physicochemistry of the peat substrate, as well as on growth and mineral nutrition of white spruce seedlings (1 + 0) under forest nursery conditions. Three treatments were used to cover the cavities of large white spruce seedlings produced in containers: silica (29 g/cavity; control treatment), calcite (24 g/cavity) and calcite + (31 g/cavity). At the end of the first growing season, the two calcite treatments significantly increased the total dry mass (28%), roots (27%) and shoot (29%) dry masses and height (24%) compared to silica treatments. Average calcium concentration and content of calcite treatments were significantly higher than that of silica treatment. [ABSTRACT FROM AUTHOR]

Research on organic electrochemical transistor (OECT) based sensors to monitor in vivo plant traits such as xylem sap concentration is attracting attention for their potential application in precision agriculture. Fabrication and electronic aspects of OECT have been the subject of extensive research while its characterization within the plant water relation context deserves further efforts. This study tested the hypothesis that the response (R) of an OECT (bioristor) implanted in the trunk of olive trees is inversely proportional to the water flux density flowing through the plant (Jw). This study also examined the influence on R of vapor pressure deficit (VPD) as coupled/uncoupled with light. R was hourly recorded in potted olive trees for a 10-day period concomitantly with Jw (weight loss method). A subgroup of trees was bagged in order to reduce VPD and in turn Jw, and other trees were located in a walk-in chamber where VPD and light were independently managed. R was tightly sensitive to diurnal oscillation of Jw and at negligible values of Jw (late afternoon and night) R increased. The bioristor was not sensitive to the VPD per se unless a light source was coupled to trigger Jw. This study preliminarily examined the suitability of bioristor to estimate the mean daily nutrients accumulation rate (Ca, K) in leaves comparing chemical and sensor-based procedures showing a good agreement between them opening new perspective towards the application of OECT sensor in precision agricultural cropping systems. [ABSTRACT FROM AUTHOR]

It is well known that trees grown on roadsides suffer from stressful environments, including poor soils, bad weather, and harmful gases from automobile exhaust. Improving the adaptability of roadside trees to adverse environments is important for urban management. An experiment was carried out with six-year-old Buxus megistophylla Levl. hedgerows, where 20 mg/L 5-aminolevulinic acids (5-ALA) solution was sprayed on the blade surface at the end of April. Three months later, plant morphology, chlorophyll fast fluorescence characteristics, antioxidant enzyme activities and the mineral element content were investigated. The results showed that leaf size and thickness were significantly greater with 5-ALA treatment, and the leaf color was also greener than those of the control. 5-ALA treatment significantly promoted the electron transfer activity of the PSII reaction center on the donor side, the reaction center itself and the receptor side. It reduced energy dissipation through the heat with increased photochemical quantum yields. The activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in leaves and roots, were stimulated by 5-ALA treatment. The content of soluble sugars and free proline in leaves was significantly increased by 5-ALA treatment, as were the absorption and accumulation of several kinds of mineral nutrient elements, such as nitrogen, phosphate, calcium, magnesium, iron, copper and boron. Additionally, 5-ALA application significantly increased the content of cadmium, mercury, chromium and lead in the roots but decreased them in the leaves. This implies that 5-ALA may induce a mechanism in B. megistophylla in which toxic elements were intercepted in roots to avoid accumulation in leaves, which ensured healthy growth of the aboveground tissues. 5-ALA may regulate the absorption and utilization of mineral nutrient elements in soil with the interception of toxic heavy metal elements in roots, promote leaf photosynthetic performance, induce the accumulation of soluble sugars and free proline, and improve the antioxidant enzyme systems for plants to adapt to the stressful environment of urban roads. These results provide a basis for 5-ALA applications alongside city roads. [ABSTRACT FROM AUTHOR]

Soil analysis is used to estimate nutrient availability, but nutrient concentrations are not always related to yield in most fruit plants, including grapevines. Thus, additional multivariate mathematical models, such as the compositional nutrient diagnosis (CND), which takes into account leaves nutrient concentration, and yield, can contribute to estimating critical levels or sufficiency bands of elements, as well as to detect deficiency and/or excess of nutrients. The aim of the present study was to establish CND standards, and the critical level and sufficiency band of nutrients, in the grapevine Vitis vinifera L., grown in a subtropical climate region. Leaves were collected in 81 vineyards in the Campanha Gaúcha do Rio Grande do Sul region, Southern Brazil, and analyzed for macroand micro-nutrient concentration. The yield of each vineyard was assessed. Grapevine nutritional status was calculated through the CND method. CND-r² indices were effective in establishing the nutritional status of grapevines for macro- and micro-nutrients as sub-optimal, excessive, or balanced. The CND methodology established the critical level and sufficiency bands of nutrients more accurately than the current recommendations for grapevines. Multi-nutrient associations were more effective than the single nutrient determination in defining the threshold of a given nutrient that can reduce grapevine yield. [ABSTRACT FROM AUTHOR]

Panicum virgatum L. (switchgrass) cultivars (‘Alamo’, ‘Cimarron’, ‘Kanlow’, ‘NL 94C2-3’, ‘NSL 2009-1’, and ‘NSL 2009-2’) were evaluated for salt tolerance in two separate greenhouse experiments. In experiment (Expt.) 1, switchgrass seedlings were irrigated with a nutrient solution at an electrical conductivity (EC) of 1.2 dS·m−1 (control) or a saline solution (spiked with salts) at an EC of 5.0 dS·m−1 (EC 5) or 10.0 dS·m−1 (EC 10) for four weeks, once a week. Treatment EC 10 reduced the tiller number by 32% to 37% for all switchgrass cultivars except ‘Kanlow’. All switchgrass cultivars under EC 10 had a significant reduction of 50% to 63% in dry weight. In Expt. 2, switchgrass was seeded in substrates moistened with either a nutrient solution of EC 1.2 dS·m−1 (control) or a saline solution of EC of 5.0, 10.0, or 20.0 dS·m−1 (EC 5, EC 10, or EC 20). Treatment EC 5 did not affect the seedling emergence, regardless of cultivar. Compared to the control, EC 10 reduced the seedling emergence of switchgrass ‘Alamo’, ‘Cimarron’, and ‘NL 94C2-3’ by 44%, 33%, and 82%, respectively. All switchgrass cultivars under EC 10 had a 46% to 88% reduction in the seedling emergence index except ‘NSL 2009-2’. No switchgrass seedlings emerged under EC 20. In summary, high salinity negatively affected switchgrass seedling emergence and growth. Dendrogram and cluster of six switchgrass cultivars indicated that ‘Alamo’ was the most tolerant cultivar, while ‘NSL 2009-2’ was the least tolerant cultivar at both seedling emergence and growth stages. A growth-stage dependent response to salinity was observed for the remaining switchgrass cultivars. ‘NSL 2009-1’ and ‘NL 94C2-3’ were more tolerant to salinity than ‘Cimarron’ and ‘Kanlow’ at the seedling emergence stage; however, ‘Kanlow’ and ‘Cimarron’ were more tolerant to salinity than ‘NSL 2009-1’ and ‘NL 94C2-3’ at the seedling growth stage. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate nutrient concentrations in the flowers, leaves (pre-flowering and grain-filling period), grains, and husks of Robusta coffee genotypes cultivated in the Amazon region, as well as to identify their genetic diversity. This experiment was carried out in Alta Floresta D'Oeste, Rondônia, Brazil, in randomized blocks with three replications; for the leaves, a factorial experimental design of sampling periods was included. The nutrient concentrations of the different evaluated organs were subjected to analysis of variance by the F test (p < 0.01), and the genetic parameters were estimated. To determine the genetic diversity, the genotypes were grouped by the UPGMA hierarchical method, and to predict it the relative importance of traits was analyzed. Genetic divergence among Coffea canephora genotypes was indicated by the leaf nutrient concentrations. At a maximum dissimilarity threshold of 82% for the genotypes, the UPGMA method formed six groups. Concentrations of nitrogen (N) and phosphorus (P) in the leaf sampling periods of pre-flowering and grain filling were not influenced by genotypes. The leaf and flower iron (Fe) concentrations contributed most to genetic divergence. For a nutritional diagnosis of Robusta coffee, it is important to take into account the comparisons of genetic diversity as well as the nutritional requirements during the flowering and grain-filling periods. [ABSTRACT FROM AUTHOR]

The effect of mineral nutrition on wilt diseases has been previously reported in many herbaceous hosts, though such an effect on Verticillium wilt in olive (Olea europaea L.; VWO), caused by Verticillium dahliae, is still uncertain. Field observations reveal that nitrogen (N) excess or imbalances of N-potassium (K) favour VWO epidemics. However, this has yet to be demonstrated. Thus, the aim of this study was to evaluate the influences of nutritional imbalances of N and K in V. dahliae infection of olive. To this end, adjusted treatments with N excess (↑N+↑Na), K deficiency (↓K) and their combination (↑N+↑Na+↓K) were evaluated on the viability of V. dahliae microsclerotia (MS), as well as on disease development in olive plants. In parallel, the potential indirect effect of the treatments on the viability of conidia and MS of V. dahliae was evaluated through the stimuli of root exudates. Treatments ↑N+↑Na and ↑N+↑Na+↓K decreased MS germination and disease progress, whereas ↓K significantly increased both parameters. Root exudates from treated plants increased the conidia germination of V. dahliae but reduced the MS germination. The results of this study will be the basis for planning further research towards a better understanding of the effect of mineral nutrition on VWO. [ABSTRACT FROM AUTHOR]

While it is generally acknowledged that drought is one of the main abiotic factors affecting plant growth, how mineral nutrition is specifically and negatively affected by water deficit has received very little attention, other than being analyzed as a consequence of reduced growth. Therefore, Brassica napus plants were subjected to a gradual onset of water deficits (mild, severe, or severe extended), and leaves were analyzed at the ionomic, transcriptomic and metabolic levels. The number of Differentially Expressed Genes (DEGs) and of the most differentially accumulated metabolites increased from mild (525 DEGs, 57 metabolites) to severe (5454 DEGs, 78 metabolites) and severe extended (9346 DEGs, 95 metabolites) water deficit. Gene ontology enrichment analysis of the 11,747 DEGs identified revealed that ion transport was one of the most significant processes affected, even under mild water deficit, and this was also confirmed by the shift in ionomic composition (mostly micronutrients with a strong decrease in Mo, Fe, Zn, and Mn in leaves) that occurred well before growth reduction. The metabolomic data and most of the transcriptomic data suggested that well-known early leaf responses to drought such as phytohormone metabolism (ABA and JA), proline accumulation, and oxidative stress defense were induced later than repression of genes related to nutrient transport. [ABSTRACT FROM AUTHOR]

Simple Summary: Variations in phosphorous (P) digestibility as a function of methodology, phosphate source, physicochemical characteristics and commercial source were evaluated in broilers. Three methodologies and two phosphates (monocalcium phosphate, MCP, and dicalcium phosphate, DCP) from three different commercial sources were used in two experiments. In the first experiment, MCP and DCP were incorporated into a P-deficient diet at two levels of inclusion and P digestibility was evaluated using three methodologies of the regression method (total excreta, marker in excreta and prececal digestibility). In the second experiment, variations in P digestibility of six phosphate sources (three MCP and three DCP) were evaluated using the total collection method. The P digestibility of MCP ranged from 75.2 to 87.4% and from 80.5 to 86.6% for DCP amongst methodologies (p > 0.05). Particle size, surface area, degree of crystallinity and impurities varied amongst commercial sources. The P digestibility of the three tested commercial sources of MCP was 79.6% (MCP1), 70.2% (MCP2) and 65.6% (MCP3); p > 0.05. The P digestibility of the three tested commercial sources of DCP was 80.1% (DCP1), 77.4% (DCP2) and 71.4% (DCP3); p > 0.05. The objective of this study was to compare the total tract (total excreta and marker) and prececal methodologies to determine phosphorus (P) digestibility and to evaluate its variation as a function of the physicochemical characteristics of the inorganic phosphate used (monocalcium, MCP and dicalcium, DCP) from different commercial sources. A total of 176 1-day-old male broilers were used in two digestibility experiments. In Experiment 1, one MCP and one DCP were incorporated in the basal diet at two levels. In Experiment 2, MCP and DCP from three commercial sources were incorporated to the basal diet at one level. Physicochemical characteristics of inorganic phosphates were examined, as well. Additionally, bone mineralization and growth performance traits were investigated in both trials. The digestibility of MCP ranged from 75.2 to 87.4% and from 80.5 to 86.6% for DCP amongst methodologies, but differences between total tract and preceal methodologies were not statistically significant. Particle size, surface area, degree of crystallinity and impurities varied amongst commercial sources. The P digestibility of the three tested commercial sources of MCP was 79.6% (MCP1), 70.2% (MCP2) and 65.6% (MCP3); p > 0.05. The P digestibility of the 3 tested commercial sources of DCP was 80.1% (DCP1), 77.4% (DCP2) and 71.4% (DCP3); p > 0.05. [ABSTRACT FROM AUTHOR]