Leaf Potassium Concentrations Research Articles

Overexpression of AtNHX1 increases leaf potassium content by improving enrichment capacity in tobacco (Nicotiana tabacum) roots.

The NHX1 gene encodes a Na+ /H+ antiporter located in the tonoplast membrane, which plays critical role in regulating plant salt tolerance. It is also involved in the uptake and accumulation of K in plants; however, its precise mechanism is unknown. In this research, we elucidated the physiological basis underlying the increases in K content induced by NHX1 . We evaluated main agronomic traits, leaf K content, K+ uptake kinetics, and root morphological and physiological characteristics from field-planted and hydroponic plants. We included a wild-type tobacco (Nicotiana tabacum ) variety (K326) and three transgenic tobacco lines (NK7, NK9, NK10) that overexpress AtNHX1 from Arabidopsis thaliana . Results demonstrated that the agronomic performance of the AtNHX1 -overexpressing tobacco lines was similar to K326 in field and hydroponic settings. The three AtNHX1 -overexpressing tobacco lines had significantly higher leaf K contents than K326. Under hydroponic condition, enhanced K uptake capacity and a larger maximum K uptake rate were seen in AtNHX1 -overexpressing tobacco lines. AtNHX1 -overexpressing lines also exhibited significantly superior root morphological and physiological traits relative to K326, including root biomass, root volume, absorption area, root activity, cation exchange capacity, soluble protein content, and H+ -ATPase activity. Overexpression of AtNHX1 in tobacco significantly improves the K uptake and accumulation. Therefore, leaf K content greatly increased in these transgenic lines in the end. Our findings strongly suggest that AtNHX1 overexpression increased leaf K content by boosting the capacity of enriching K in tobacco roots, thereby advancing the understanding of the function of AtNHX1 .

Foliar Nourishment with Different Potassium Sources to Maximize Yield Through Improving Nutrient Uptake in Citrus Aurantifolia Trees Grown in Potassium-Deficient Soil

AbstractPurpose: Based on its crucial regulatory role in several biochemical processes, potassium (K) is considered to greatly influence fruit yield and quality. Methods: Two field experiments were carried out in two seasons (2021 and 2022) to explore the response of lemon (Baladi cv.) trees grown in K-deficient soil to four different K fertilizer sources applied individually as a foliar spray. K citrate (KC1 = 1.3 vs. KC2 = 2.6 g L− 1), K nitrate (KN1 = 1.5 vs. KN2 = 3.0 g L− 1), K tartrate (KT1 = 1.5 vs. KT2 = 3.0 g L− 1), and K thiosulfate (KS1 = 1.25 vs. KS2 = 2.5 g L− 1) were applied three times, and the treated trees were compared with untreated trees. This study was established with a randomized complete block design (RCBD) using four replicates. Results: The findings revealed that the KC treatment, regardless of dosage, showed clear superiority in terms of the values for the leaf phosphorus (%), manganese, and zinc contents (mg kg− 1), as well as fruit firmness, fruit dry matter, and total soluble solids in both seasons. In second place was the KT treatment, which yielded the best values for fruit length and width in 2021, the best values for leaf nitrogen and iron contents and fruit weight and volume in 2022, and the best values regarding variable fluorescence by maximum fluorescence, relative chlorophyll content (SPAD readings), the photosynthetic performance index, total acidity, and vitamin C in both seasons. Furthermore, the highest total lemon yield and leaf potassium contents were achieved with the KN treatment in both seasons. The heat map illustrating that most of the studied characteristics were positively and significantly correlated with total lemon yield (TLY). Conclusions: The KN treatment, closely followed by the KC treatment, is regarded to be the best treatment for most of the studied trails.

Exogenous putrescine application imparts salt stress-induced oxidative stress tolerance via regulating antioxidant activity, potassium uptake, and abscisic acid to gibberellin ratio in Zinnia flowers

This research was conducted to investigate the efficacy of putrescine (PUT) treatment (0, 1, 2, and 4 mM) on improving morphophysiological and biochemical characteristics of Zinnia elegans “State Fair” flowers under salt stress (0, 50, and 100 mM NaCl). The experiment was designed in a factorial setting under completely randomized design with 4 replications. The results showed that by increasing the salt stress intensity, the stress index (SSI) increased while morphological traits such as plant height decreased. PUT treatments effectively recovered the decrease in plant height and flower quality compared to the not-treated plants. Treatment by PUT 2 mM under 50 and 100 mM salt stress levels reduced the SSI by 28 and 35%, respectively, and increased plant height by 20 and 27% compared to untreated plants (PUT 0 mM). 2 mM PUT treatment also had the greatest effect on increasing fresh and dry biomass, number and surface area of leaves, flower diameter, internodal length, leaf relative water content, protein contents, total chlorophyll contents, carotenoids, leaf potassium (K+) content, and K+/Na+ ratio in treated plants compared to untreated control plants. The treatment of 2 mM PUT decreased the electrolyte leakage, leaf sodium (Na+) content, H2O2, malondialdehyde, and proline content. Furthermore, PUT treatments increased the activity of defense-related enzymes including catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and phenylalanine ammonium lyase (PAL), and reduced the abscisic acid (ABA) content while increased the level of gibberellin (GA) content compared to untreated samples under all different levels of salinity stress. In this research, enhancing the plant’s antioxidant system, increasing K+ absorption, K+/Na+ ratio, and reducing the ABA/GA ratio are likely the most important mechanisms of PUT treatment, which improved growth, and maintained the visual quality of zinnia flowers under salt stress conditions.

Combined application of biochar and peatmoss for mitigation of drought stress in tobacco

Drought poses a significant ecological threat that limits the production of crops worldwide. The objective of this study to examine the impact of soil applied biochar (BC) and peatmoss (PM) on the morpho-biochemical and quality traits of tobacco plants under drought conditions. In the present experiment work, a pot trial was conducted with two levels of drought severity (~ well-watered 75 ± 5% field capacity) and severe drought stress (~ 35 ± 5% field capacity), two levels of peatmoss (PM) @ 5% [PM+ (with peatmoss) and PM- (without peatmoss)] and three levels of rice straw biochar (BC0 = no biochar; BC1 = 150 mg kg− 1; and BC2 = 300 mg kg− 1 of soil) in tobacco plants. The results indicate that drought conditions significantly impacted the performance of tobacco plants. However, the combined approach of BC and PM significantly improved the growth, biomass, and total chlorophyll content (27.94%) and carotenoids (32.00%) of tobacco. This study further revealed that the drought conditions decreased the production of lipid peroxidation and proline accumulation. But the synergistic approach of BC and PM application increased soluble sugars (17.63 and 12.20%), soluble protein (31.16 and 15.88%), decreased the proline accumulation (13.92 and 9.03%), and MDA content (16.40 and 8.62%) under control and drought stressed conditions, respectively. Furthermore, the combined approach of BC and PM also improved the leaf potassium content (19.02%) by limiting the chloride ions (33.33%) under drought stressed conditions. Altogether, the balanced application of PM and BC has significant potential as an effective approach and sustainable method to increase the tolerance of tobacco plants subjected to drought conditions. This research uniquely highlights the combined potential of PM and BC as an eco-friendly strategy to enhance plant resilience under drought conditions, offering new insights into sustainable agricultural practices.

Leaf Functional Traits and Their Influencing Factors in Six Typical Vegetation Communities.

Leaf functional traits (LFTs) have become a popular topic in ecological research in recent years. Here, we measured eight LFTs, namely leaf area (LA), specific leaf area (SLA), leaf thickness (LT), leaf dry matter content (LDMC), leaf carbon content (LCC), leaf nitrogen content (LNC), leaf phosphorus content (LPC), and leaf potassium content (LKC), in six typical vegetation communities (sclerophyllous evergreen broad-leaved forests, temperate evergreen coniferous forests, cold-temperate evergreen coniferous forests, alpine deciduous broad-leaved shrubs, alpine meadows, and alpine scree sparse vegetation) in the Chayu River Basin, southeastern Qinghai-Tibet Plateau. Our aim was to explore their relationships with evolutionary history and environmental factors by combining the RLQ and the fourth-corner method, and the method of testing phylogenetic signal. The results showed that (i) there were significant differences in the eight LFTs among the six vegetation communities; (ii) the K values of the eight LFTs were less than 1; and (iii) except for LCC, all other LFTs were more sensitive to environmental changes. Among these traits, LA was the most affected by the environmental factors, followed by LNC. It showed that the LFTs in the study were minimally influenced by phylogenetic development but significantly by environmental changes. This study further verified the ecological adaptability of plants to changes in environmental factors and provides a scientific basis for predicting the distribution and diffusion direction of plants under global change conditions.

Effect of Nano Urea on Leaf Nutrients and Some Quality Parameters of Tea (Camellia sinensis (L) O. Kuntze)

Some important parameters of tea on mature plants of TV 23 clone were studied after application of Nano-urea as foliar spray at Experimental Garden for Plantation Crops, Assam Agricultural University, Jorhat during the period 2021-2022. The usage of "Nano Urea" (Liquid), a novel product created and patented by Indian Farmers Fertilizer Cooperative Limited (IFFCO), is projected to replace the use of urea granules, one of the most widely used fertilizers in the world. Leaf nutrients i.e., nitrogen, phosphorus, potassium and quality parameters i.e., Caffeine, polyphenol were observed after application of nano urea. Leaf nitrogen, leaf phosphorus and leaf potassium were found to be increased with the application of higher dose of Nano Urea. Leaf nitrogen was observed maximum (4.57%) in the plot where 0.4% Nano-urea applied in three sprays. Total phosphorus content of leaf was found to be the highest in treatment T7(0.423%) the lowest was observed in treatment T0 (0.370%). Total potassium content of leaf was the highest in treatment T7 (2.517%) and lowest K2O content was observed in treatment T0 (2.013%) which was a control. In quality parameters, it was found that application of Nano Urea showed significant impact on the total caffeine content of tea leaf. The highest value of caffeine was found in treatment T7 (3.233%) and lowest was found in treatment T0 (3.10%) (control).

UAV hyperspectral image acquisition and processing, an application for nutrient estimation of rice in Vietnam

Hyperspectral imagery obtained from Unmanned Aerial Vehicles (UAVs) is increasingly employed to investigate nutrient concentrations in vegetation. The deployment of a hyperspectral camera on a UAV, flight planning, image acquisition, preprocessing of hyperspectral data, and the subsequent estimation of nutrient concentrations in vegetation are facing challenges. These challenges manifest as geometric, spectral distortions, and the abundance of numerous spectral bands. This study seeks to guide on mitigating the impact of issues encountered during an experiment to estimate nutrient concentrations in rice leaves using UAV hyperspectral images. An industrial hexagonal drone equipped with a push-broom hyperspectral camera featuring 122 bands within the Visible to Near-Infrared (VIS-NIR) wavelength range (400-960 nm) is employed to collect data over a 1-hectare testing rice field. Models for estimating Leaf Phosphorus Concentration (LPC) and Leaf Potassium Concentration (LKC) are developed based on the correlation between hyperspectral images, characterized by a 3 cm spatial resolution, and 162 LPC and 162 LKC reference data points. Utilizing various vegetation indices for LPC and LKC estimation, the outcomes reveal that a combination of band wavelengths at 838 nm and 734 nm is effective for LPC estimation, yielding a Root Mean Square Error (RMSE) of 27.1%. Conversely, LKC estimation exhibits an RMSE of 38.8% with an insignificant correlation between LKC and the current wavelength ranges. Above all, this study is a primary example of the utilization of UAV hyperspectral data in precision agriculture in Vietnam.

Changes in Amino Acid Accumulation and Nitrogen, Phosphorus, and Potassium Concentrations in Leaves of Date Palm (Phoenix dactylifera L.) Seedlings Exposed to UV Light Stress

Changes in Amino Acid Accumulation and Nitrogen, Phosphorus, and Potassium Concentrations in Leaves of Date Palm (Phoenix dactylifera L.) Seedlings Exposed to UV Light Stress

Efficiency of Nitrogen Fertilization in Millet Irrigated with Brackish Water

Nitrogen fertilization can provide greater nutritional support and mitigate salt stress in the millet crop. The aim of this study was to evaluate the physiological responses and agronomic performance of millet crop subjected to nitrogen fertilization and irrigation water salinity. The study was carried out in a greenhouse, using a completely randomized design in a 5 × 2 factorial scheme, with four replications, with five doses of nitrogen (40; 60; 80; 100 and 120 kg ha−1 of N), and two levels of electrical conductivity for the irrigation water: 0.3 and 4.0 dS m−1. We concluded that salt stress increased leaf sodium levels and had a negative impact on stalk and panicle dry mass, leaf gas exchange, mineral element concentrations (K, P, and Ca), and water use efficiency. The use of lower-salinity water associated with increased nitrogen fertilization provides greater stalk and panicle dry mass, photosynthesis, water use efficiency, chlorophyll index, leaf potassium concentration, and biomass production. The adverse effects of salt stress were evident in decreased transpiration and stomatal conductance, alongside reductions in leaf phosphorus and calcium levels, coupled with elevated leaf sodium concentrations, particularly as nitrogen fertilization rates increased in potted millet plants. These findings offer insights for devising strategies aimed at mitigating the detrimental effects of salt stress on millet plant nutrition through targeted nitrogen fertilization approaches.

Optimizing oil palm farming: Soil quality, fertilization and agro-environmental performance

The essential role of fertilization in the management of oil palm plantations cannot be overstated, with the understanding that effective strategies must be fine-tuned to accommodate the diversity of soil types present. The nuanced response of oil palm to fertilization under different soil conditions underscores the critical nature of this research. This study investigates the relationship between oil palm farming practices and agro-environmental performance of plantations. This research aims to understand the complex mechanisms influencing plantation productivity. Five agronomic field experiments were carried out on various soil types (Podzol, Inceptisol, Peat) during 2022. These experiments involved various types of soil and used different plant materials in a total land area of 33 hectares. The results of the peat soil trials revealed a positive effect of RP fertilizer on leaf phosphorus (P) content and a visible gradient in potassium (K) content with different doses of KCl. Average plantation yields peaked in 2022, showing the best yields ever recorded. On the contrary, experiments in podzolic soils showed that oil palm responded better to organic fertilizers than to mineral fertilizers in podzolic soils. The inceptisol soil revealed a significant increase in leaf potassium (K) content with KCl dose, confirming the positive effect of fresh oil palm empty fruit bunches (EFB) on potassium levels. In particular, EFB acts as a good K fertilizer, positively influencing the K content but negatively affecting the calcium content (Ca) due to K/Ca antagonism. These findings emphasize the need for diversified agricultural strategies to optimize oil palm cultivation, increase productivity, and reduce dependence on external input.

Nitrogen-fixing and non-nitrogen-fixing legume plants differ in leaf nutrient concentrations and relationships between photosynthetic and hydraulic traits.

Legumes account for a significant proportion of plants in the terrestrial ecosystems. Nitrogen (N)-fixing capability of certain legumes is a pivotal trait that contributes to their ecological dominance. Yet, the functional traits and trait relationships between N-fixer and non-N-fixer legumes are poorly understood. Here, we investigated 27 functional traits associated with morphology, nutrients, hydraulic conductance and photosynthesis in 42 woody legumes (19N-fixers and 23 non-N-fixers) in a common garden. Our results showed that N-fixers had higher specific leaf area, photosynthetic phosphorus (P)-use efficiency, leaf N, and iron concentrations on both area and mass basis, N/P ratio, and carbon (C) to P ratio, but lower wood density, area-based maximum photosynthetic rate (Aa), photosynthetic N-use efficiency, leaf mass- and area-based P and molybdenum and area-based boron concentrations, and C/N ratio, compared with non-N-fixers. The mass-based maximum photosynthetic rate (Am), stomatal conductance (gs), intrinsic water-use efficiency (WUEi), mass- and area-based leaf potassium and mass-based boron concentrations, leaf hydraulic conductance (Kleaf), and whole-shoot hydraulic conductance (Kshoot) showed no difference between N-fixers and non-N-fixers. Significant positive associations between all hydraulic and photosynthetic trait pairs were found in N-fixers, but only one pair (Kshoot-Aa) in non-N-fixers, suggesting that hydraulic conductance plays a more important role in mediating photosynthetic capacity in N-fixers compared with non-N-fixers. Higher mass-based leaf N was linked to lower time-integrated gs and higher WUEi among non-N-fixer legumes or all legumes pooled after phylogeny was considered. Moreover, mass-based P concentration was positively related to Am and gs in N-fixers, but not in non-N-fixers, indicating that the photosynthetic capacity and stomatal conductance in N-fixers were more dependent on leaf P status than in non-N-fixers. These findings expand our understanding of the trait-based ecology within and across N-fixer and non-N-fixer legumes in tropics.

Alpha and beta diversity of functional traits in subtropical evergreen broad-leaved secondary forest communities.

Intra-speciic variation is the main source of functional trait diversity and has similar ecological effects as inter-speciic variation. We studied 79 species and 3546 individuals from 50 ixed monitoring plots in subtropical evergreen broad - leaved secondary forests in Zhejiang Province, China. Using trait gradient analysis, we examined nine traits (speciic leaf area, leaf dry matter content, wood density, leaf area, chlorophyll content, leaf nitrogen content, leaf phosphorus content, leaf potassium content, and nitrogen-phosphorus ratio) by decomposing species functional traits into alpha (within-community) and beta (among-communities) measure the impact of environmental gradients and the presence of other species on the variation of traits. All nine functional traits showed some degree of differentiation in the forest communities, with a greater range of variation in alpha values than in beta values . Correlations were signiicantly different between the trait differences in the communities. The alpha values of each trait showed a higher correlation with other components than the beta values. The factors affecting intra-speciic trait variation were relatively complex. The alpha component had a more signiicant and stronger effect on intra-speciic trait variation compared to the beta component. Abiotic factors, such as soil nutrient content, soil nitrogen-phosphorus content, directly affected the beta component. In contrast, biotic factors, such as tree height variation, had a direct and stronger effect on the alpha component. Our results demonstrate that alpha and beta components, as independent differentiation axes among coexisting species, have different sensitivities to different environmental factors and traits in different ecological strategies and spatial scales. Trait gradient analysis can more clearly reveal the variation patterns of species traits in communities, which will help to understand the scale effects and potential mechanisms of trait relationships.

Leaf stoichiometry of potassium, calcium, and magnesium in tropical plants: Responses to climatic and geographical variations—A case study from Hainan Island

AbstractGrasping how climate change will affect the tropical region's leaf potassium, calcium, and magnesium content is pivotal for enhancing our comprehension of plant stoichiometry. Currently, there is limited research on leaf potassium, calcium, and magnesium in tropical plants, which is particularly evident with the increasing importance of tropical rainforest biodiversity studies. This study investigated the impact of geographical and climatic factors on the leaf potassium, calcium, and magnesium content in 346 plants (including woody plants, herbs, and vines) on Hainan Island. The findings demonstrated that the average leaf potassium, calcium, and magnesium contents were 5.77, 11.86, and 2.92 mg·g−1, respectively, which were less than that in the Chinese flora. Mean annual precipitation (MAP) has a promoting effect on leaf potassium content (p < 0.05), suggesting that artificial potassium fertilization is needed due to the increasing MAP. Leaf potassium and magnesium content were positively correlated with latitude (p < 0.05) and longitude (p < 0.01); and there was a negative correlation between leaf calcium content and latitude (p < 0.05), showing that geographical factors have a significant impact on the potassium, calcium, and magnesium content of plant leaves. Additionally, the variables regulating leaf potassium, calcium, and magnesium varied across woody plants, herbs, and vines. Therefore, it is necessary to make corresponding adjustments according to local conditions and the plant functional types during nutrient management. In conclusion, this study sheds light on their potential responses to global changes and is instrumental in informing the management of these nutrients in tropical rainforest plants.

Estimation model of potassium content in cotton leaves based on hyperspectral information of multileaf position

Potassium (K) is a highly mobile nutrient element that continuously adjusts its demand strategy among and within cotton leaves through redistribution. This indirectly leads to variations in the leaf potassium content (LKC, %) at different leaf positions. However, owing to the interaction between light and leaf age, leaf sensitivity at different positions to this change varies, including the reflection and absorption of the spectrum. How to selecting the optimal monitoring leaf position is an important factor in quickly and accurately evaluation of cotton LKC using spectral remote sensing technology. Therefore, this study proposes a comprehensive multileaf position estimation model based on the vertical distribution characteristics of LKC from top to bottom. This is aimed at achieving an accurate estimation of cotton LKC and optimizing the strategy for selecting the monitored leaf position. Between 2020 and 2021, we collected hyperspectral imaging data of the main stem leaves at different positions from top to bottom (Li, i=1, 2, 3, …, n), during the cotton budding, flowering, and boll setting stages. Vertical distribution characteristics, sensitivity differences, and spectral correlations of LKC at different leaf positions were investigated. Additionally, the optimal range of the dominant leaf position for monitoring was determined. Partial least squares regression (PLSR), random forest regression (RFR), support vector machine regression (SVR), and the entropy weight method (EWM) were used to establish LKC estimation models for single leaf and multileaf positions. The results showed a vertical heterogeneous distribution of cotton LKC, with LKC initially increasing and then gradually decreasing from top to bottom, and the average LKC of cotton reaches its maximum value at flowering stage. The upper leaf position demonstrated greater sensitivity to K and exhibited a stronger correlation with the spectrum. The selected dominant leaf positions for the three growth stages were L1–L5, L1–L4, and L1–L2, respectively. Based on the dominant leaf position monitoring range, the optimal single leaf position models for estimating LKC during the three growth stages were PLSR-L4, PLSR-L1, and SVR-L2, with The coefficient of determination of the validation set (R2val) of 0.786, 0.580, and 0.768, and the root-mean-square error of the validation set (RMSEval) of 0.168, 0.197, and 0.191, respectively. The multileaf position LKC estimation model was constructed by EWM with R2val of 0.887, 0.728, and 0.703, and RMSEval of 0.134, 0.172, and 0.209, respectively. In contrast, the newly developed multileaf position comprehensive estimation model yielded superior results, improving the stability of the model on the basis of high accuracy, especially during the budding and flowering stages. These findings hold significant importance for investigating cotton LKC spectral models and selecting suitable leaf positions for field monitoring.

Crosstalk of sucrose, potassium, and magnesium on growth, yield, and carbohydrate partitioning in bell pepper (Capsicum annuum L.) under poor light conditions

Bell pepper has received high demand due to its high nutritional value and contained antioxidant compounds. This research aimed to evaluate the effects of sucrose and some minerals on morpho-physiological characteristics, yield parameters, and carbohydrate partitioning in the bell pepper. The pot experiment was outlined hydroponically in a factorial format based on a completely randomized design. The first factor, sucrose, was sprayed in two concentrations (0 and 0.5% w/v) and the second factor, mineral nutrition, consisted of four levels (control, magnesium nitrate 0.5% w/v, potassium nitrate 0.5% w/v, magnesium nitrate 0.25% w/v + potassium nitrate 0.25% w/v). Results indicated that sucrose 5 + combined magnesium & potassium nitrate was superior in all of the biomass and yield parameters. In this combined treatment, fruit yield per plant and fruit vitamin C increased up to 44.03% and 47.71% in comparison with control. The highest leaf-soluble carbohydrate was recorded in plants treated with sucrose 5 + combined magnesium & potassium nitrate which was not significantly different from other contained sucrose treatments. The highest fruit soluble carbohydrate was observed in sucrose 5 + combined magnesium & potassium nitrate treatment as well, but its difference was not significant from sucrose 5 + potassium nitrate. The highest leaf potassium concentration was seen in three treatments that combined sucrose and minerals. The treatment of combined magnesium & potassium nitrate contributed to more leaf magnesium concentration compared with other nutrient treatments. In total, sucrose spray alongside combined magnesium & potassium nitrate led to higher carbohydrate accumulation in fruit, causing yield increment and nutritional value enhancement in bell peppers.

Nutrient distribution in various tissues of Licorice (Glycyrrhiza glabra L.) and the influence of soil fertility on the levels of its bioactive compounds

This study aimed to optimize the production of licorice (Glycyrrhiza glabra L.) in field conditions using two licorice ecotypes and various types of nutrient sources. Licorice yield, leaf and root nutrient content, and its bioactive compounds were assessed. Mycorrhiza inoculation resulted in the highest rhizome dry weight in the Lalehzar (101.3 g) and Kermanshah (395.6 g) ecotypes in the first and second years, respectively. Rhizome dry weight was higher than the roots in both ecotypes. Two years old Kermanshah ecotype exhibited the highest root dry weight by using urea. The harvest index increased in Lalehzar ecotype by application of vermicompost in the first year and cow manure coupled with plant growth-promoting bacteria (PGPB) in the second year. Nitrogen content in leaves and roots significantly increased in the Kermanshah ecotype using cow manure and PGPB. Application of mycorrhiza (in Lalehzar ecotype) and cow manure combined with urea (in Kermanshah ecotype) led to leaf phosphorus (P) content improvement. The highest root P content in Lalehzar and Kermanshah ecotypes achieved by using cow manure and urea, respectively. Fertilization by urea and mycorrhiza led to higher leaf potassium (K) content in Kermanshah and Lalehzar, respectively, while urea yielded the highest root K content in the Kermanshah ecotype. Root glycyrrhizic acid (GA) content peaked in the Kermanshah ecotype with cow manure and PGPB (138 and 372.8 mg g-1 DW in the first and second years, respectively). Rhizome GA content performed better in the Lalehzar ecotype using cow manure and PGPB (191.34 mg g-1 DW, first year) and in the Kermanshah ecotype with cow manure and urea (239.62 mg g-1 DW, second year). Fertilizers had not significant effect on glabridin (GL) content. Notably, GA and GL exhibited a negative correlation with potassium and nitrogen. This study highlights the importance of balanced nutrient management for licorice cultivation.

AGRONOMIC EFFICIENCY OF REKAL REMINERALIZER IN SOYBEAN AND MAIZE CROPS

Remineralization regards using rocks as both conditioners and nutrient sources for agricultural soils; it also works as essential basis for degraded or depleted soil recovery. The aim of the present assay is to assess the performance of Rekal remineralizer and its effects on soybean and maize cultures, which were used as test plants. The following soil types were used in the experiment: Yellow Oxisol with sandy loam texture and Red Oxisol with clayey texture. The research was carried out in greenhouse, at the Agronomics School of Federal University of Goiás, Goiânia City, Goiás State. Experimental treatments consisted in using different Rekal remineralizer doses (0, 30, 60, 120 and 240 kg ha-1 K2O) to compare the results to those of FMX remineralizer products and potassium chloride (KCl), at the dose of 60 kg ha-1. Plant development variables (height, diameter and number of leaves), soil and leaf potassium content, calcium and magnesium content, CEC and soil base saturation, soybean grain yield, maize green mass yield and the relative efficiency of Rekal using in comparison to both FMX remineralizer and potassium chloride synthetic fertilizers were assessed. Results have shown that Rekal remineralizer presents agronomic efficiency comparable to that of KCl and FMX remineralizer. Using Rekal remineralizer can improve and keep important soil parameters, such as CEC, soil base saturation and calcium, magnesium and potassium content.

Nutritional changes in trees during drought‐induced mortality: A comprehensive meta‐analysis and a field study

AbstractBoth macronutrients and micronutrients are essential for tree growth and development through participating in various ecophysiological processes. However, the impact of the nutritional status of trees on their ability to withstand drought‐induced mortality remains inconclusive. We thus conducted a comprehensive meta‐analysis, compiling data on 11 essential nutrients from 44 publications (493 independent observations). Additionally, a field study was conducted on Pinus sylvestris L. trees with varying drought‐induced vitality loss in the “Visp” forest in southern Switzerland. No consistent decline in tree nutritional status was observed during tree mortality. The meta‐analysis revealed significantly lower leaf potassium (K), iron (Fe), and copper (Cu) concentrations with tree mortality. However, the field study showed no causal relationships between nutritional levels and the vitality status of trees. This discrepancy is mainly attributed to the intrinsic differences in the two types of experimental designs and the ontogenetic stages of target trees. Nutrient reductions preceding tree mortality were predominantly observed in non‐field conditions, where the study was conducted on seedlings and saplings with underdeveloped root systems. It limits the nutrient uptake capacity of these young trees during drought. Furthermore, tree nutritional responses are also influenced by many variables. Specifically, (a) leaf nutrients are more susceptible to drought stress than other organs; (b) reduced tree nutrient concentrations are more prevalent in evergreen species during drought‐induced mortality; (c) of all biomes, Mediterranean forests are most vulnerable to drought‐induced nutrient deficiencies; (d) soil types affect the direction and extent of tree nutritional responses. We identified factors that influence the relationship between tree nutritional status and drought survival, and proposed potential early‐warning indicators of impending tree mortality, for example, decreased K concentrations with declining vitality. These findings contribute to our understanding of tree responses to drought and provide practical implications for forest management strategies in the context of global change.

Response of Strawberry Plants to Foliar Application with Seaweeds Extract and Benzylaenine

This research was carried out in a greenhouse located south of Baghdad, Yusufiyah, Abu Halan area, in fall season at 20/10/2021, on Ruby gem strawberry cultivar. To find out the effect of spraying with growth regulator Benzyl adenine BA and seaweed extract on strawberry runners and some vegetative and fruiting characteristics. The study included implementation of a factorial experiment with two factors, first factor is spraying of growth regulator BA with three concentrations: 0, 50, 100 PPM as B0, B1, B2, respectively and second factor is seaweed extract spray with four concentrations: 0, 2, 4, 6 mg.L as A0, A1, A2, A3, respectively. treatments were distributed randomly in a randomized complete block design (RCBD) experiment. As experiment included 12 treatments with three replications and 12 plants for each experimental unit, thus the number of plants included in the experiment was 432 plants. The results showed that, seaweed extract spray at 6 mg/L.(A3) significantly increased in leaves number of 15.40 leaf.plant-1 and highest runner’s number of 4.77 runner.plant-1, highest leaf chlorophyll content of 0.825 %, highest leaf nitrogen content of 1.908 %, highest leaf phosphor content of 0.570 % and highest leaf potassium content of 1.87 %.

Response of some Growth Traits of Maize Plants to Conventional and Nano-Fertilizers

The Agricultural Research Station in the university city associated with the College of Agriculture at the University of Kufa undertook a fall 2022-2023 field experiment. The study examined the effects of zinc and iron nanoparticles at 2g.l-1 or 3g.l-1, conventional iron and zinc fertilizer at 3g.l-1, and distilled water on maize plant growth and development. A three-replication Randomized Completely Block Design (RCBD) factorial experiment was done. Nano-fertilization with nano-zinc at 3g.l-1 produced the best results across various vegetative development indicators. Plant height rate, stem diameter, leaf chlorophyll, nitrogen, and phosphorus content are these indicators. However, 3g.l-1 nano iron increased leaf area the highest, reaching 0.424 m2.plant-1. This treatment also produced the most rows per ear and the maximum leaf potassium concentration. In contrast, 1.5 g.L-1 traditional zinc and 1.5 gm.L-1 conventional iron fertilizer produced better vegetative growth and production. These included plant height, average stem diameter, leaf chlorophyll, and leaf elements (NPK). Additionally, 3 g.L-1 conventional iron produced the maximum leaf area. Overall, the 1.5 g.L-1 nano-zinc and 1.5 g.L-1 nano-iron fertilizer combination had higher vegetative growth rates than other combinations. However, the combination of 1 g.L-1 nano-iron and 1.5 g.L-1 nano-zinc had the maximum leaf area and potassium concentration.