Potassium Concentration Research Articles

Effect of preservation on changes in the volume of corneal endothelial cells in an environment with a high concentration of potassium

The experimental study of preservation length on the effect of high potassium concentration in the medium on the volume of human corneal endothelial cells was done. The results of the study of individual samples of fragments of donor material and the values calculated using joined data after hypothermic preservation for 4 and 10 days are presented. The increase of the time when cornea samples are kept in preservation medium (Eusol-C) at 4℃ led to a decrease in the average value (M ± SEM) of cell swelling indicator (N) in a potassium medium from 1.055 ±0.001; n = 982 to 1.014±0.001; n = 338; after 4 and 10 days, respectively. Student’s-t test for independent samples showed a high degree of significance for the difference between these values (p = 2E-76). Identification of the proportion of cells capable to swell in a medium with a high content of potassium ions (N 1), reflecting the electrogenic activity in these cells, showed a decrease of this indicator in the studied groups with increasing duration of preservation (94.3% and 56.8% after 4 and 10 days, respectively). Based on the results of the study, it is suggested that the values of endothelial cells swelling in a potassium environment can serve as indicators of the cells’ ability to restore electrogenic transport. It is concluded that the study of cell swelling in a medium with a high content of potassium ions can provide information for predicting the functionality of the graft.

Catalytic Effects of Potassium Concentration on Steam Gasification of Biofuels Blended from Olive Mill Solid Wastes and Pine Sawdust for a Sustainable Energy of Syngas

The effect of potassium impregnation at different concentrations during gasification, under nitrogen/water steam atmosphere, of char produced via pyrolysis of olive mill residues blended or not with pine sawdust was investigated. Three concentrations (0.1 M, 0.5 M, and 1.5 M) of potassium carbonate solution (K2CO3) were selected to impregnate samples. First, four types of pellets were prepared; one using exhausted olive mill solid waste (G) noted (100G) and three using G blended with pine sawdust (S) in different percentages (50%S–50%G (50S50G); 60%S–40%G (60S40G); 80%S–20%G (80S20G)). Investigations showed that when isothermal temperature increases during the gasification conducted with two water steam percentages of 10% and 30%, the reactivity increases with potassium concentration up to 0.5 M, especially for 100G. Still, higher catalyst concentration (1.5 M) showed adverse effects attributable to silicon release and char pore fouling. Moreover, the effect of the steam concentration on the gasification reactivity was significant with the non-impregnated sample 100G. Finally, a kinetic study was carried out to determine the different kinetic parameters corresponding to the Arrhenius law.

Controllable mechanism of hazardous jarosite transformation into recyclable hematite in the leaching solution of secondary zinc oxide powder

The controlled synthesis of recyclable hematite in the leaching solution of secondary zinc oxide powder is an urgent problem in the chemical industry and metallurgy fields. In this paper, the effects of the temperature, agitation speed, and seed addition on the contents of iron, sulfur, potassium, sodium, and zinc in the iron removal residues, as well as the iron concentration in the supernatant after iron removal were systematically studied. In addition to the temperature control already reported, we found that the agitation speed can also control the transformation between jarosite and hematite phases. The content of jarosite in the residues can be effectively controlled by adjusting the agitation speed, thereby significantly improving the quality of hematite product, as indicated by SEM-EDS and XRD results. Under temperature of 185 °C, an agitation speed of 500 rpm, and a seed addition of 15 g/L, the iron, sulfur and zinc contents in the filter residues and the iron concentration in the supernatant were 59%, 3.22%, 0.92%, and 4.182 g/L, respectively. Kinetic studies show that the rapid oxidation kinetics is not conducive to the formation of high-quality hematite products. These results can directly guide the process of transformation of harmful jarosite into recyclable hematite from the leaching solution of secondary zinc oxide powder, which is of great practical significance for the controlled and waste-free removal of iron from aqueous solutions in the chemical industry and metallurgy fields.

Assessment of Soil Fertility Status in Vegetable Growing Area of Daman-Palung, Nepal

Soil fertility assessment is essential for sustainable planning for a particular area. Considering this, a study was conducted in November 2018, to determine the soil fertility status of the vegetable growing area of Makwanpur district, Nepal. In total, 50 soil samples were collected randomly from a depth of 0-20 cm using a soil sampling auger. A standard analytical method was used to analyze the texture, soil pH, (Organic matter (OM), Nitrogen (N), Phosphorus (P2O5), and Potassium (K2O) status of samples at the National Soil Science Research Centre, Khumaltar. The sand, silt and clay content were 45.67±2.08, 35.6±51.37 and 18.49±0.93 respectively and were indicated as loam and sandy loam in texture. The soil was moderately acidic (pH 5.11±0.5) in nature. Soil organic matter ranged from low to medium but the medium (3.37±1.72 %) was prevalent. Total nitrogen content (0.22±0.01 %) and available phosphorus (230.58 ±85.61 ppm), were found to be high. Furthermore, available potassium (97.4±70.04 ppm) content was medium in the soil. The purpose of this soil fertility assessment is to help researchers and farmers in Daman, Palung know the soil fertility status of their area and to guide sustainable soil fertility practices. This soil fertility assessment aims to help researchers and farmers in Daman, Palung understand soil fertility status and determine the best soil fertility practices for their area.

Machine learning-based analysis of nutrient and water uptake in hydroponically grown soybeans

Recent advancements in sustainable agriculture have spurred interest in hydroponics as an alternative to conventional farming methods. However, the lack of data-driven approaches in hydroponic growth presents a significant challenge. This study addresses this gap by varying nitrogen, magnesium, and potassium concentrations in hydroponically grown soybeans and conducting essential nutrient profiling across the growth cycle. Statistical techniques like Linear Interpolation are employed to interpolate nutrient data and a feature selection pipeline consisting of chi-squared testing methods, Linear Regression with Recursive Feature Elimination (RFE) and ExtraTreesClassifier have been used to select important nutrients for predicting water uptake using non-parametric regression methods. For different nutrient growth media, i.e. for soybeans grown in Hoagland + Nitrogen and Hoagland + Magnesium media, the Random Forest regressor outperformed other methods in predicting water uptake, achieving testing Mean Squared Error (MSE) scores of 24.55 (R2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{R}}^{2}$$\\end{document} score 0.63) and 8.23 (R2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{R}}^{2}$$\\end{document} score 0.81), respectively. Similarly, for soybeans grown in Hoagland + Potassium media, Support Vector Regression demonstrated superior performance with a testing MSE of 4.37 and R2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{R}}^{2}$$\\end{document} score of 0.85. SHapley Additive exPlanations (SHAP) values are examined in each case to elucidate the contributions of individual nutrients to water uptake predictions. This research aims to provide data-driven insights to optimize hydroponic practices for sustainable food production.

Enrichment of Phytopathogen Dominated by Volutella in the Rhizosphere May Be an Important Cause of Continuous Cropping Obstacles in Sweet Potatoes

ABSTRACTObstacles related to the continuous cropping of sweet potatoes (Ipomoea batatas (L.) Lam.) restrict its intensive production. However, the effects of continuous cropping on soil properties and/or the rhizosphere microbial community are largely unclear. In this study, we analyzed changes in rhizosphere soil chemical properties and microbial communities of sweet potatoes across different cultivation years. We observed that the microbial diversity and complexity of the fungal ecological network in rhizosphere soils of sweet potatoes were decreased after 5 years of continuous cropping, with significant enrichment in Sphingobium, Gemmatimonas, Volutella, and Neoidriella. Tuber yield, soil pH, and available potassium (AK) content were significantly reduced after continuous cropping, with the soil microbial community having the highest correlation with pH, AK, and ammonium nitrogen (NH4+‐N). Specifically, soil pH and AK were positively correlated with Bacillus and Gaiella, and negatively correlated with some plant‐pathogenic fungi (Volutella and Neoidriella), while NH4+‐N showed the opposite trend. In addition, soil pH, AK, and the relative abundance of Bacillus were positively correlated with tuber yield, while Volutella showed the opposite trend. In summary, the continuous cropping of sweet potatoes negatively affects rhizosphere soil health, resulting in imbalanced soil fertility and an increased abundance of pathogens. These results improve our understanding of factors driving obstacles faced with the continuous cropping of sweet potatoes, enabling future studies and the development of technologies to overcome these obstacles.

Study on the Changes in the Microbial Community in Rhizosphere Soil of Blueberry Plants at Different Growth Stages

In order to clarify the relationship between mineral nutrients and rhizosphere microorganisms at different growth and development stages of blueberry (Vaccinium spp.), this work studied the dynamic changes in element content and microbial quantity in different parts of blueberry plants. The test material was a 12-year-old half-highbush blueberry variety (‘Beilu’). The changes in the mineral nutrient elements in leaves, branches and the soil of blueberry plants were studied at the full bloom stage (T1), green fruit stage (T2), mature stage (T3) and late mature stage (T4), and the correlations of the average contents of mineral elements in the four periods were studied. The bacterial community in the rhizosphere soil was determined and analyzed using 16S rRNA high-throughput sequencing technology. The results showed that the changes in other mineral elements in various parts of blueberry plants varied in different periods. Nitrogen (N) showed a downward trend in branches, leaves and soil, especially in leaves (p < 0.05). The N contents in T2, T3 and T4 decreased by 9.9%, 26.4% and 29.9%, respectively. The N contents in the leaves and branches showed a downward trend at different growth stages, especially in leaves. The phosphorus (P) content in leaves showed a trend of increasing first and then decreasing, while it continued to increase in branches. The content of potassium (K) in leaves changed significantly, where it increased first and then decreased. The content of calcium (Ca) in leaves decreased first and then increased, while the content of magnesium (Mg) in branches and leaves decreased first and then increased, and the relative change was significant. The contents of iron (Fe) and zinc (Zn) in leaves decreased first and then increased, while the contents of manganese (Mn) and copper (Cu) were relatively stable. Cu decreased first and then increased in leaves and soil, and it increased first and then decreased in branches. The mineral nutrients in different growth stages of blueberry showed significant correlation in leaves, branches and soil. Mn in leaves was significantly positively correlated with P, Ca, Mg, Mn, Cu and Zn in soil (p < 0.01). Nitrogen and calcium in leaves were significantly correlated with manganese and phosphorus in soil, respectively. Ca in branches was significantly positively correlated with N and K in soil and was significantly positively correlated with Zn in soil (p < 0.01). Magnesium was significantly negatively correlated with iron in soil. The bacterial community structure of the blueberry rhizosphere soil changed significantly over time (p < 0.05), and the relative abundance showed the following trend: T4 > T2 > T3 > T1. At the phylum level, Proteobacteria, Acidobacteria, Actinobacteria, Chloroflexi and Verrucomicrobia were the dominant bacteria in different periods. Candidatus solibacter and Bryobacter were significantly higher in T1 and T3 than in T1 and T4. Bradyrhizobium flora increased significantly at T3. Sphingomonas increased significantly at T1 (p < 0.05).

Effects of Soil Nutrient Restoration Aging and Vegetation Recovery in Open Dumps of Cold and Arid Regions in Xinjiang, China

Open-pit coal mining inevitably damages the soil and vegetation in mining areas. Currently, the restoration of cold and arid open-pit mines in Xinjiang, China, is still in the initial exploratory stage, especially the changes in soil nutrients in spoil dumps over time. Dynamic remote sensing monitoring of vegetation in mining areas and their correlation are relatively rare. Using the Heishan Open Pit in Xinjiang, China, as a case, soil samples were collected during different discharge periods to analyze the changes in soil nutrients and uncover the restoration mechanisms. Based on four Landsat images from 2018 to 2023, the remote sensing ecological index (RSEI) and fractional vegetation cover (FVC) were obtained to evaluate the effect of mine restoration. Additionally, the correlation between vegetation changes and soil nutrients was analyzed. The results indicated that (i) the contents of nitrogen (N), phosphorus (P), potassium (K), and organic matter (OM) in the soil increased with the duration of the restoration period. (ii) When the restoration time of the dump exceeds 5 years, N, P, K, and OM content is higher than that of the original surface-covered vegetation area. (iii) Notably, under the same restoration aging, the soil in the artificial mine restoration demonstration base had significantly higher contents of these nutrients compared to the soil naturally restored in the dump. (iv) Over the past five years, the RSEI and FVC in the Heishan Open Pit showed an overall upward trend. The slope remediation and mine restoration project significantly increased the RSEI and FVC values in the mining area. (v) Air humidity and surface temperature were identified as key natural factors affecting the RSEI and FVC in cold and arid open pit. The correlation coefficients between soil nutrient content and vegetation coverage were higher than 0.78, indicating a close and complementary relationship between the two. The above results can clarify the time–effect relationship between natural recovery and artificial restoration of spoil dumps in cold and arid mining areas in Xinjiang, further promoting the research and practice of mine restoration technology in cold and arid open pits.

Plant growth promoting bacteria promote rice growth cultivated in two different sandy soils subjected distinct climates conditions.

Sandy soils contain around 70% sand in their composition, making them highly fragile and susceptible to land degradation. Practices such as no-tillage cultivation, the use of bioinoculants, and the application of organic amendments can restore the organic matter in these soils, ensuring sustainable production. In this context, this work aimed to study the microbiological aspects of two sandy soil areas (Brazilian Northeast and South) under contrasting climatic conditions (tropical and temperate). With this purpose, prokaryotic communities were evaluated, and the plant growth-promoting potential of isolated bacteria was assessed by rice inoculation in sandy soil. Despite the high sand content in both soils, soil from the NE was related to the highest phosphorous, calcium, potassium, copper, sodium, zinc, magnesium, and manganese contents, organic matter percentage, and pH. The Shannon diversity index indicated that prokaryotic communities in NE were more diverse than in SU, and PCA revealed that microbial composition exhibited distinct patterns. The rice inoculation experiments were executed to verify if the bacterial isolates displayed a similar growth promotion potential when inoculated in sandy soil areas subjected to different climatic conditions. When all PGP characteristics evaluated were pooled in a PCA, a similar pattern was observed for SU and NE. Burkholderia sp. SU94 was related to highest PGP characteristics evaluated. Paraburkholderia sp. NE32 showed similar results to those of the non-inoculated control. This similar effect of rice growth in the Northeast and South of Brazil suggests that isolate SU94 adapts to different environmental conditions.

Virtual Instruments for Peak-Overlapping Studies to Determine Low- and High-Concentration Components with Ion Chromatography: Potassium and Sodium.

We developed the LabVIEW-based virtual instruments (VIs) to bridge a gap in commercial software and to enable systematic peak-overlapping studies to recognise the concentration levels enabling reliable simultaneous determination of major and minor constituents in samples with wide concentration proportions. The VIs were applied to a case study of the ion chromatographic determination of potassium as minor and sodium as a major ion with an IonPac CS12A column and 50 μL injection loop. Two successive studies based on multilevel two-factorial response surface experimental designs, (1) a model peak-overlapping study based on single-ion injections, and (2) an accuracy and precision study, provided guidelines for real sample analyses. By adjusting sample dilutions so that the sodium mass concentration was set to 340 mg/L, the simultaneous determination of potassium in the presence of sodium was possible in samples with sodium over potassium concentration ratios between 14 and 341. The relative expanded uncertainty associated with potassium ion determination was between 0.52 and 4.4%, and the relative bias was between -3.8 and 1.9%. We analysed Ringer's physiologic solutions, standard sea, trisodium citrate anticoagulant, and buffered citrate anticoagulant solutions. We confirmed that the VI-supported peak-overlapping studies contributed to the quality of results by enabling the evidence-based choices of concentration levels adjusted by a dilution.

Investigating the effect of changing the K:Ca ratio in nutrient solution on the quantitative and qualitative yield of Lilium spp. in hydroponic cultivation

Nowadays, hydroponics is an advanced method for plant production in agriculture. The optimal balance of nutrients in the nutrient solution is crucial to enhance plant performance in this method. To investigate the effect of potassium to calcium (K:Ca) ratio change in nutrient solution on quantitative and qualitative yield of lilies in hydroponic culture, a randomized complete block design with nine treatments and three replications was designed and carried out in 30% perlite and 70% sand. The treatments included different concentrations of calcium (Ca) at three levels of 0, 3, and 6 mM and different concentrations of potassium (K) at three levels of 0, 3, and 6 mM in the Hoagland nutrient solution, with K:Ca ratios of 0:0, 0:3, 0:6, 3:0, 3:3, 3:6, 6:0, 6:3, and 6:6. Results showed that the presence of different levels of potassium and calcium was found to enhance the quality of lilies by influencing nutrient uptake. The results indicated that nutrient solutions containing different ratios of K:Ca had a significant effect on reproductive height, the number of aborted buds, stem diameter at the 5% level and the number of flowers, the number of leaves, the fresh weight of shoots, the dry weight of shoots, and the longevity at the 1% level. The highest yield in terms of longevity (17 days), the number of flowers, the number of leaves, and absorption of potassium and calcium were observed in the nutrient solution with a 3:3 K:Ca ratio.

SOME PHYSICOCHEMICAL AND MICROBIOLOGICAL PROPERTIES OF TRADITIONAL HELETE CHEESE

In this study, some chemical and microbiological properties and mineral content of Helete cheese produced locally from goat milk were investigated. Dry matter, fat, protein, ash, pH, acidity, total mesophilic-aerobic bacteria, total mold, yeast, Staphylococcus aureus, total coliform and Escherichia coli and calcium, magnesium, zinc, phosphorus and potassium content were investigated in cheese samples. At the end of the research, it was determined that Helete cheese was in accordance with the standards specified in the Turkish Food Codex and Helete cheese was classified as semi-hard and full fat cheese.

Impact of Ultra-Processed Foods on Food Sustainability: Exposure Assessment and Health Implications.

Excessive consumption of ultra-processed food (UPF) is a global health concern as-sociated with an increased incidence of non-communicable diseases. UPFs are characterized by their extensive industrial processing and high content of additives, preservatives, chemicals, and artificial ingredients that are used to mask defects or inferior ingredients of end food products, presenting a multifaceted challenge to contemporary society. Exposure assessment showed that almost 50% to 30% of the energy consumption per day comes from UPFs. The more processed a food is, the less likely it is to be healthy and nutritious. UPFs affect human health by increasing the risk of obesity, heart disease, cancer, depression, diabetes, etc., as these foods are typically made up of a large number of preservatives, high content of fats, sodium, and sugars, and low contents of protein, fiber, and potassium. The ingredients required for the production of UPFs are commonly derived from intensive monoculture and livestock of raw foods. This, in turn, exerts imminent effects on agriculture, biodiversity, and the global food system by altering the bioavailability of nutrients within agricultural soil, thereby increasing the dependency on ferti-lizers and insecticides. Recent studies have shown that over-consumption of UPF has an effect on culinary traditions, loss of biodiversity, human well-being, and food system sustainability. Therefore, for better food system sustainability, the consumption of UPFs should be reduced, and we should move toward minimal processing technologies, preferably for seasonal and or-ganic local products. Based on available data, there is an urgent need to implement policies and regulations for the agro-food industry to include nutritional and environmental criteria. This review explains the different dimensions of UPFs in relation to health, nutrition, environment, current challenges, future innovations, and wider sustainability concerns.

Physico-chemical characteristics and quality assessment of soil in parts of the Banganga Basin in northeastern Rajasthan, NW India.

Soil is a vital natural resource that has a bearing on any developmental activity. A database comprising primary physicochemical characteristics and soil suitability would assist the planners in devising an appropriate land use policy and any intervention strategy for soil quality improvement. The physicochemical characteristics of soils in parts of the Banganga Basin, located in the semi-arid terrain of NW India were evaluated mainly through surface samples and sub-surface ones wherever sections were exposed in stream banks. The soil in the studied terrain is a Quaternary age, pale brown to dark brown and occasionally red, alluvial soil. Sandy loam is the dominant soil type, while sandy soil and loamy sand types also occur. The soil maintains a depth-wise consistency in physicochemical characteristics. The average soil pH value is 8.55, indicating a slightly alkaline and healthy soil. The soil has a high available nitrogen content (0.53 to 2.24%), adequate available phosphorus (23.58 and 62.18mg/kg), and low potassium (22.5 and 200mg/kg) contents. The organic carbon, Mg, and Ca levels are generally on the lower side. A consistency in overall soil characteristics is evident in the narrow range of the Soil Quality Index, varying between 10 and 14, and soil can be categorized into three categories with overlapping soil qualities.

Production and Quality Evaluation of Yogurt and Watermelon Juice Blends

The study investigated the effect of incorporation of watermelon juice in yogurt on the quality of the blends. Yogurt and watermelon (Citrullus lanatus) juice were produced. The watermelon juice was used to substitute 0, 10, 20, 30, 40, and 50% of yogurt. The chemical composition, antioxidant activity, physicochemical, and sensory properties of the blends were determined using standard procedures. The pH of the yogurt and watermelon juice were 4.57 and 5.78, respectively and varied from 5.18 -6.04 for the blends. The moisture, protein, ash, fat and carbohydrate contents decreased with increase in the amount of watermelon juice in the blends. The vitamin C, calcium, zinc and magnesium contents increased while the phosphorus and potassium contents decreased with increased level of watermelon juice in the blends. The phenols and carotenoids contents increased while the flavonoids content decreased with increase in the level of watermelon juice in the blends. The antioxidant activity using DPPH assay varied with the samples where yogurt had higher radical scavenging activity than the watermelon juice. The radical scavenging activities and the ferric reducing antioxidant property (FRAP) values also increased with the level of watermelon juice in the blends. The FRAP values for yogurt and watermelon juice were 1.22 and 1.58mg/ml, respectively and increased to a range of 1.29 -3.70 mg/ml for the blends. The yogurt had higher scores than the watermelon juice for all the sensory attributes evaluated. The scores for the sensory attributes decreased with increase in the level of watermelon juice in the blends. However, the scores for the blend containing 10 % watermelon juice for all the attributes were not significantly different (p>0.05) from those of the yogurt. Therefore, it is concluded that watermelon juice could be used to substitute 10% yogurt without adversely affecting the qualities of the blends.

Allelochemicals Released from Rice Straw Inhibit Wheat Seed Germination and Seedling Growth

Recently, returning rice straw to soil has become a common problem in wheat production because it causes decreased wheat seedling emergence. Allelopathy is an important factor affecting seed germination. However, the effects of rice straw extracts on wheat seed germination and seedling growth remain unclear. Wheat seeds and seedlings were treated with 30 g L−1 of rice leaf extracts (L1), 60 g L−1 of rice leaf extracts (L2), 30 g L−1 of rice stem extracts (S1), 60 g L−1 of rice stem extracts (S2) and sterile water (CK) to study the allelopathic effects of rice straw extracts on wheat seed germination and seedling growth. The α-amylase and antioxidant enzyme activities in wheat seeds; the agronomic traits, photosynthetic indicators, and nutrient contents of wheat seedlings; and the phenolic acids in rice stem extracts were determined. Common allelochemicals, including 4-hydroxybenzoic acid, hydrocinnamic acid, trans-cinnamic acid, vanillic acid, benzoic acid, protocatechualdehyde, caffeic acid, syringic acid, sinapic acid, and salicylic acid, were detected in rice stem extracts. Low-concentration rice leaf and stem extracts (30 g L−1) had no effect on the germination rate of wheat seeds. High-concentration (60 g L−1) rice stem and leaf extracts decreased the seed germination rate by 11.00% and 12.02%. Rice stem extract (60 g L−1) decreased the α-amylase activity, and gibberellin content of wheat seeds but increased superoxide dismutase, peroxidase, and catalase activities and malondialdehyde content in wheat seeds. Allelochemicals entered the internal tissues of wheat seeds, where they decreased the gibberellin content and α-amylase activity and increased the antioxidant enzyme activity, ultimately leading to an inhibitory effect on seed germination. Rice stem and leaf extracts decreased the SPAD value and photosynthetic indicators of wheat seedlings. Rice stem extract (60 g L−1) decreased the fresh weight and root length of wheat seedlings by 31.37% and 45.46%. Low-concentration rice leaf and stem extract (30 g L−1) had no effect on the nutrient contents of wheat seedlings. Rice leaf and stem extracts (60 g L−1) decreased the nitrogen and potassium contents of wheat seedlings. These results indicated that low-concentration rice leaf and stem extract (30 g L−1) had no effect on wheat seed germination and the high-concentration rice stem extract (60 g L−1) released allelochemicals and inhibited wheat seed germination and seedling growth. These findings provide a basis for the improvement of straw return techniques.

Effects of Different Weeding Methods on Soil Physicochemical Properties, Root Morphology, and Fruit Economic Traits in Camellia oleifera Abel. Plantations

Soil physicochemical properties, root characteristics, and fruit economic traits were determined in Camellia oleifera plantations under spontaneous vegetation + mowing (W1), spontaneous vegetation + glyphosate (W2), and no weeding (CK) treatments. Compared with CK, W1 reduced soil bulk density and increased total nitrogen, total phosphorus, ammonium nitrogen, nitrate nitrogen, and effective potassium content. W2 treatment resulted in higher bulk density than W1 and lower water-holding capacity, total nitrogen, total phosphorus, total potassium, ammonium nitrogen, nitrate nitrogen, and available potassium of the soil. Generally, both W1 and W2 inhibited weed morphological traits while favoring the C. oleifera root system, with the W1 treatment resulting in the greatest increase. Fruit transverse diameter, longitudinal diameter, yield, and oil yield were higher in W1 than in CK and W2 treatments. Weed root systems and C. oleifera root systems ultimately affect oil production and yield by affecting bulk density, ammonium nitrogen, nitrate nitrogen, fruit transverse diameter, seed yield, and seed kernel oil content. In summary, W1 treatment improved the physicochemical properties, root growth, fruit growth, and soil quality in C. oleifera plantations.

Biochemical changes in the aetiology of floppy kid syndrome in goat kids

AbstractIn the herd, 20 of 75 goat kids born became progressively ill. Twelve affected kids, aged 4–9 days, exhibited muscle weakness, pain without fever, diarrhoea and dehydration. Their health deteriorated rapidly, and within a few hours, one kid died. The results of the blood test revealed severe metabolic acidosis, hypokalaemia and changes in urea concentrations. Floppy kid syndrome was diagnosed. Treatment was initiated to correct the acid–base balance, and all affected kids were temporarily separated from their mothers. All the treated kids recovered. Before the onset of clinical signs, elevated urea concentrations and differences in maternal blood potassium levels were observed. This is the first report on changes in potassium concentrations in periparturient dams of goat kids with and without floppy kid syndrome, as well as the first report on changes in urea concentrations in kids before the onset of clinical signs.

Calcium-activated chloride channels. Role of potassium ions

Using the patch-clamp method in the whole-cell configuration, it was shownthat external potassium ions play an important role in the regulation of calcium-activated chloride currents. A clear dependence of the amplitude of chloride currents on changes in the concentration of external potassium is shown. Changes in concentration of sodium, magnesium and calcium ions from membrane outside have no so significant effect, like outside potassium ions. The effect of potassium on the amplitudes of chloride currents is significantly greater than the effect it has on other cell ionic currents — sodium, potassium, cation. There is reason to believe that a change in the amplitudes of chloride currents contributes to the pathophysiological processes characteristic of hypokalemia and hyperkalemia.

Contrasting Life-Form Influences Guam Ficus Foliar Nutrient Dynamics

Tropical trees that remain evergreen and exhibit leaf litterfall that is gradual over time coexist with trees that are seasonally deciduous and exhibit pulsed litterfall. The manner in which these trees acquire, store, and contribute nutrients to the biogeochemical cycle may differ. Green and senesced leaves from deciduous Ficus prolixa trees were compared with those from Ficus tinctoria on the island of Guam. The results enabled stoichiometry and resorption calculations. F. prolixa’s young green leaf nitrogen (N) and potassium (K) concentrations were double, and the phosphorus (P) concentration was triple, those of F. tinctoria. Concentrations converged as the leaves aged such that no differences in concentration occurred for senesced leaves, indicating that nutrient resorption proficiency did not differ between the two species. In contrast, the resorption efficiency was greater for F. prolixa than F. tinctoria for all three nutrients. The N:P values of 6–11 and K:P values of 5–7 were greater for young F. tinctoria leaves than young F. prolixa leaves. The N:K values were 1.1–1.6 and did not differ between the two species. No differences in pairwise stoichiometry occurred for senesced leaves for any of the nutrients. These Guam results conformed to global trends indicating that seasonally deciduous plants are more acquisitive and exhibit greater nutrient resorption efficiency. The differences in how these two native trees influence the community food web and nutrient cycling lies mostly in the volume and synchronicity of pulsed F. prolixa litter inputs, and not in differences in litter quality. These novel findings inform strategic foresight about sustaining ecosystem health in Guam’s heavily threatened forests.