Root deformation affects mineral nutrition but not leaf gas exchange and growth of Genipa americana seedlings during the recovery phase after soil flooding

Root deformation (RD) caused by errors in the pricking out process are irreversible and very difficult to detect in container-grown seedlings at the time of planting in the field. The objective of this study was to evaluate the effects of RD on leaf gas exchange, growth, biomass allocation and mineral nutrition of G. americana seedlings during the recovery phase after soil flooding. Four-months-old seedlings, with and without RD, were flooded for 42 days and their recovery was evaluated 28 days after soil drainage. There were no significant interactions between RD and soil flooding for all leaf gas exchange, growth and mineral nutrition after soil drainage, with the exception of leaf P concentrations. In plants with no RD, the P concentration in leaves of non-flooded plants was significantly higher than that of plants with RD. Soil flooding and RD did not influence leaf or root N concentrations or whole-plant N content. RD increased the K concentration in the roots, but not in the leaves. Changes in the nutrient concentrations in leaves and roots indicate that RD may affect physiological performance of seedlings after planting in the field.

Effects of Salt Stress on Absorption And Distribution of Osmotic Ions in Wheat Seedlings

Effects of salt stress on absorption and distribution of osmotic ions in wheat seedlings were studied with 4 winter wheat varieties under NaCl stress by exploring dynamic changes of Ca2+, K+, Na+, Ca2+/Na+, K+/Na+ and Na+ limiting ability. The results showed that the contents of K+, Ca2+ and the K+/Na+ ratio gradually decreased in a manner of both salt concentration dependent and stress time dependent. The extent of reduction of K+ and Ca2+ in root was much more severe than that in shoot. The ability of Na+ limiting in QM6 and DK961 was stronger than that in JM22 and QF1. These results indicate that the maintenance of higher Na+ content in root, Na+ limiting ability, Ca2+ and K+ concentration will be the main physiological traits for the salt-tolerance of wheat. Bangladesh J. Bot. 50(4): 1209-1214, 2021 (December)

Potassium Effects on NCC Are Attenuated during Inhibition of Cullin E3–Ubiquitin Ligases

The thiazide-sensitive sodium chloride cotransporter (NCC) plays a vital role in maintaining sodium (Na+) and potassium (K+) homeostasis. NCC activity is modulated by with-no-lysine kinases 1 and 4 (WNK1 and WNK4), the abundance of which is controlled by the RING-type E3 ligase Cullin 3 (Cul3) and its substrate adapter Kelch-like protein 3. Dietary K+ intake has an inverse correlation with NCC activity, but the mechanism underlying this phenomenon remains to be fully elucidated. Here, we investigated the involvement of other members of the cullin family in mediating K+ effects on NCC phosphorylation (active form) and abundance. In kidneys from mice fed diets varying in K+ content, there were negative correlations between NCC (phosphorylated and total) and active (neddylated) forms of cullins (Cul1, 3, 4, and 5). High dietary K+ effects on phosphorylated NCC were attenuated in Cul3 mutant mice (CUL3-Het/Δ9). Short-term (30 min) and long-term (24 h) alterations in the extracellular K+ concentration did not affect cullin neddylation levels in ex vivo renal tubules. In the short term, the ability of high extracellular K+ to decrease NCC phosphorylation was preserved in the presence of MLN4924 (pan-cullin inhibitor), but the response to low extracellular K+ was absent. In the long term, MLN4924 attenuated the effects of high extracellular K+ on NCC phosphorylation, and responses to low extracellular K+ were absent. Our data suggest that in addition to Cul3, other cullins are involved in mediating the effects of K+ on NCC phosphorylation and abundance.

Oil Palm (Elaeis Guineensis Jacq.) Genetic Differences in Mineral Nutrition (Part III): Specific Leaflet Mineral Concentrations of High-Yielding Oil Palm Progenies and their Implications for Managing K And Mg Nutrition

Background and aims: In oil palm, similar fertilization treatments can result in leaflet potassium and magnesium concentrations that vary significantly from one progeny to another. This hinders the development of standardized fertilizer recommendations for this crop, as they are usually calculated based on optimum leaflet nutrient concentrations.Methods: 4-high-yielding oil palm progenies with contrasting leaflet K and Mg concentrations (C1, C2, and C3 of Deli x La Mé origin and C4 of Deli x Yangambi origin) were treated with combinations of 3-levels of KCl and MgSO4, in a completely randomized split-plot factorial design with 6-replicates, where progenies were a sub-factor.Results: For a given level of KCl or MgSO4, different leaflet K and Mg concentrations were found between progenies (p < 0.0001). Leaflet K concentration and yield response to KCl applications revealed that the four oil palm progenies have different optimum leaflet K concentrations. In our study period (5-8 YAP), progenies C1 and C3 showed their highest fresh fruit bunch (FFB) yields (13.62 and 16.54 t ha-1 year-1, respectively) at K2, whereas progenies C2 and C4 showed their highest yields (14.62 and 12.39 t ha-1 year-1, respectively) at K1. Conclusion: Our study highlighted specific optimum leaflet K and Mg concentrations for different oil palm progenies in a given environment. It paves the way for adopting K and Mg fertilizer application rates adapted to specific requirements of each type of oil palm planting material.

Tuning Potassium Fertilization to Improve pH and Acidity in Glera Grapevine (Vitis vinifera L.) under a Warming Climate

Potassium concentration in grape berries can affect acidity and pH in must and wines. Under the current warming scenario, where preserving equilibrated value for these grape parameters is increasingly challenging, K fertilization could represent a tool to manage grape composition. In this study, the effect of potassium fertilization was investigated over 4 years (2013–2016) in field-grown grapevines (Vitis vinifera cv. Glera). Four different potassium rates (0, 15, 30, 60 kg K2O ha−1 year−1) were tested and agronomic responses, grape quality as well as K concentration in the berry were recorded over the four years. At harvest, yield parameters and total soluble solids were unaffected by potassium fertilization. On the contrary, the titratable acidity of the musts was increased by the higher rate of potassium (K60), and both tartaric and malic acids showed higher values when the K rate was higher. K fertilization did not affect the pH, as all the treatments displayed comparable pH values and in an optimal range for winemaking. Overall, in our experimental conditions, medium potassium inputs showed better results on Glera grape quality compared to low K rates, by promoting higher titratable acidity levels without altering the pH in musts.

Study the radioactive concentration for soil samples contaminated with depleted uranium in Al-Nahrawan site at Baghdad governorate using high purity germanium detector

This study is investigating the radioactivity in soil samples at the Al-Nahrawan site. The radiation survey appears there are 3000 square meters area are contaminated with DU in AL-Nahrawan site identified using Geiger–Müller (GM) for radiation survey and gamma spectrometry for 52 soil samples analysis taken from AL-Nahrawan site at different depths (0-70) cm and different locations. The results of gamma analysis using high-purity germanium show that the ratio between 235U/238U is less than 0.00720 (neutral ratio), and it has different values from 0.002-0.00588, and the average value of radioactive nuclides concentration for (238U, 235U and 40K) are (76019.61, 259.55 and 147.5) Bq/kg respectively, these values are higher than the (BG) radioactive concentration levels in Iraq for (238U and 235U) isotopes, and the analysis of 40K concentration appeared in the acceptable limits. The health effects of depleted uranium in the human body it is exposed to many health troubles through the entry of uranium oxide particles.

Potassium effects on NCC are attenuated during inhibition of Cullin E3-ubiquitin ligases

The thiazide sensitive sodium-chloride co-transporter (NCC) plays a vital role in maintaining sodium (Na+) and potassium (K+) homeostasis. NCC activity is modulated by the with-no-lysine kinases 1 and 4 (WNK1 and WNK4), the abundance of which are controlled by the RING-type E3 ligase Cullin 3 (Cul3) and its substrate adapter Kelch-like protein 3. Dietary K+ intake has an inverse correlation with NCC activity, but the mechanism underlying this phenomenon remains to be fully elucidated. Here, we investigated the involvement of other members of the Cullin family in mediating K+ effects on NCC phosphorylation (active form) and abundance. In kidneys from mice fed diets varying in K+ content, there were negative correlations between NCC (phosphorylated and total) and active (neddylated) forms of Cullins (Cul1, 3, 4 and 5). High dietary K+ effects on phosphorylated NCC were attenuated in Cul3 mutant mice (CUL3-Het/Δ9). Short-term (30 min) and long-term (24 h) alterations in the extracellular K+ concentration did not affect Cullin neddylation levels in ex vivo renal tubules. Short-term, the ability of high extracellular K+ to decrease NCC phosphorylation was preserved in the presence of MLN4924 (pan Cullin inhibitor), but the response to low extracellular K+ was absent. Long-term, MLN4924 attenuated the effects of high extracellular K+ on NCC phosphorylation and responses to low extracellular K+ were absent. Our data suggest that in addition to Cul3, other Cullins are involved in mediating the effects of K+ on NCC phosphorylation and abundance.

Seasonal changes of macronutrients concentration in olive trees grown in acid and in alkaline soils

Leaf samples from mature olive (Olea europaea L. cv. ‘Kalamon’) trees were collected monthly from April 2018 to March 2019 from two olive orchards, cultivated one in acid and one in alkaline soil, located in Western Greece. Nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) concentrations in the leaves were determined and seasonal variation curves were calculated for each nutrient and orchard. The seasonal concentration patterns of N, P, K, Ca, and Mg nutrients were almost similar in both soils. Seasonal variation nutrient curves independently of soil acidity varied according to vegetation stages and no significant differences in nutrient concentrations were observed at different development stages between olives grown in the acid or the alkaline soils, with only one exception the leaf K concentration. The nutrient concentration measured in wintertime was at a sufficient level for optimum olive growth in both orchards. These concentrations could be used as reference values for leaf analysis interpretation and for developing an optimum fertilization program under Mediterranean climatic conditions.

Electrochemical and Fluorescent Properties of Crown Ether Functionalized Graphene Quantum Dots for Potassium and Sodium Ions Detection

The concentration of sodium and potassium ions in biological fluids, such as blood, urine and sweat, is indicative of several basic body function conditions. Therefore, the development of simple methods able to detect these alkaline ions is of outmost importance. In this study, we explored the electrochemical and optical properties of graphene quantum dots (GQDs) combined with the selective chelating ability of the crown ethers 15-crown-5 and 18-crown-6, with the final aim to propose novel composites for the effective detection of these ions. The results obtained comparing the performances of the single GQDs and crown ethers with those of the GQDs-15-crown-5 and GQDs-18-crown-6 composites, have demonstrated the superior properties of these latter. Electrochemical investigation showed that the GQDs based composites can be exploited for the potentiometric detection of Na+ and K+ ions, but selectivity still remains a concern. The nanocomposites showed the characteristic fluorescence emissions of GQDs and crown ethers. The GQDs-18-crown-6 composite exhibited ratiometric fluorescence emission behavior with the variation of K+ concentration, demonstrating its promising properties for the development of a selective fluorescent method for potassium determination.

Root K Affinity Drivers and Photosynthetic Characteristics in Response to Low Potassium Stress in K High-Efficiency Vegetable Soybean

Significant variations of potassium absorption and utilization exist in vegetable soybean. Pot and hydroponic experiments were carried out to examine the characteristics of root potassium (K) affinity-associated drivers and photosynthesis in vegetable soybean (edamame) [Glycine max (L.) Merr.] with different K efficiency. Two K high-efficiency vegetable soybean genotypes (Line 19 and Line 20) and two K low-efficiency genotypes (Line 7 and Line 36) were investigated in low K and normal K conditions. The root of K high-efficiency genotypes had a higher K+ affinity associated with a higher maximum K+ uptake rate (Imax), but lower Michaelis constant for K+ absorption (Km) and lower compensation concentration for K+ uptake (Cmin). Seedlings of K high-efficiency genotypes also had higher root vigor [triphenyl tetrazolium chloride (TTC) reduction method] and greater absorbing activity (methylene blue method), especially in the low K condition. Furthermore, the root bleeding-sap rate of K high-efficiency genotypes in low K stress was 9.9–24.3% greater than that of normal K conditions, which was accompanied by a relatively higher K concentration of root bleeding-sap in contributing to K+ upward flux. The root of K high-efficiency vegetable soybean genotypes exhibited K+ high-affinity and driving advantages. Photosynthetic parameters of K high-efficiency vegetable soybean genotypes were less affected by low K stress. Low K stress decreased the net photosynthetic rate of K high-efficiency genotypes by 6.1–6.9%, while that of K low-efficiency genotypes decreased by 10.9–15.7%. The higher chlorophyll (Chl) a/b ratio with enhanced relative content of Chl a in response to low K stress might be an adapted mechanism for K high-efficiency genotypes to maintain photosynthetic capacity. Stronger root K affinity drivers associated with photosynthetic adaptability to low K stress are the key factors in determining the K high-efficiency of vegetable soybeans.