scholarly journals Long-term effect of low potassium fertilization on its soil fractions

2014 ◽  
Vol 60 (No. 8) ◽  
pp. 358-363 ◽  
Author(s):  
M. Madaras ◽  
M. Koubová ◽  
M. Smatanová
Keyword(s):  
Agricultural Soils ◽  
Application Rate ◽  
The Czech Republic ◽  
Xrd Diffraction ◽  
Long Term Effect ◽  
Low Potassium ◽  
Low K ◽  
Calculated Average ◽  
K Depletion

In the Czech Republic, negative potassium (K) budget in agricultural soils is caused by non-fertilization by K and by a decline of manure application. We investigated soil available, fixed (acid-extractable, K<sub>fix</sub>) and structural K pools in the field trial with graduated K application rate, established in 1972 at 8 sites of different climate and soils. The content of K-bearing minerals was evaluated on semi-quantitative scale by XRD diffraction. K-feldspars were a dominant source of structural K. Total soil K consisted of 1.7&ndash;7.1% of fixed K, which was in a positive relation to mixed-layer phyllosilicates. Differences in available K in treatments with K budget lower than &ndash;30 kg K/ha/year were small compared to those of fixed K. In control treatments, calculated average depletion of available K was&nbsp;&ndash;18 kg K/ha/year and the average depletion of fixed K was &ndash;12 kg K/ha/year; however at sites of higher altitude fixed K depletion prevailed. Fixed K accounted for 6&ndash;31% of the K budget. In negative K budget, monitoring of K<sub>fix</sub> is advisable to avoid fertility loss of soil with low K supplying capacity.

scholarly journals Polychlorinated dibenzo-p-dioxines and dibenzofurans in agricultural soils of the Czech Republic

2011 ◽  
Vol 51 (No. 10) ◽  
pp. 464-468 ◽  
Author(s):  
R. Vácha ◽  
M. Vysloužilová ◽  
V. Horváthová
Keyword(s):  
Czech Republic ◽  
Agricultural Soils ◽  
Lower Intensity ◽  
The Czech Republic ◽  
Background Value ◽  
Different Sources ◽  
Sludge Application

The set of 102 samples of agricultural soils was taken for the study of the load of agricultural soils with polychlorinated dibenzo-p-dioxins and dibenzofuranes (PCDDs/Fs). The background value of PCDDs/Fs in agricultural soils of theCzech Republicwas determined. The soils with different sources of the load of PCDDs/Fs were compared. It was concluded that fluvisols in fluvial zones and soils with long-term sludge application are soils with the highest contents of PCDDs/Fs. The soils affected by imission outputs show a lower intensity of the load with PCDDs/Fs that is characterised by higher content of toxic congeners.

Atrioventricular block in low potassium and K dependence of the nodal resting potential

1986 ◽  
Vol 64 (5) ◽  
pp. 531-538 ◽  
Author(s):  
E. Ruiz-Ceretti ◽  
A. Ponce Zumino
Keyword(s):  
Conduction Block ◽  
Resting Potential ◽  
Long Term Effects ◽  
Progressive Decline ◽  
Outward Currents ◽  
Low Potassium ◽  
Middle Node ◽  
Low K ◽  
Maximum Rate Of Rise

A progressive conduction block leading to atrioventricular dissociation develops in perfused rabbit hearts within 20–30 min of exposure to Krebs containing 0.5 mM potassium (low K). A decrease in potassium permeability resulting in membrane depolarization (as seen in Purkinje fibers) could be responsible for the loss of excitability in nodal cells. We investigated the K dependence of the resting potential and the long-term effects of low K perfusion on the resting and action potentials of nodal cells in rabbit hearts. The resting potential of atrial, atrionodal, and nodal cells varied by 5 2, 41, and 34 mV per decade of change in Ko within the range of 5–50 mM K. Hyperpolarization of the resting membrane, a progressive decline in action potential amplitude, and a decrease in maximum rate of rise were observed in nodal fibers when exposed to low K. Loss of propagated activity occurred in the middle node within 20–30 min while the cells remained hyperpolarized. There was no evidence of electrogenic Na extrusion and it seems that the low nodal resting potential results from a high resting PNa/PK permeability ratio. The early decrease in rate of rise in low K probably reflects an increase in K-dependent outward currents, whereas the progressive deterioration and final loss of conducted electrical activity may result from an accumulation of internal Na and Ca overload produced by low K inhibition of the Na pump.

scholarly journals Genome-Wide Analysis of HAK/KUP/KT Potassium Transporter Genes in Banana (Musa Acuminata L.) and Their Tissue-Specific Expression Profiles Under Potassium Stress

2021 ◽  
Author(s):  
Siwen Liu ◽  
Bangting Wu ◽  
Yanling Xie ◽  
Sijun Zheng ◽  
Jianghui Xie ◽  
...  
Keyword(s):  
Expression Profiles ◽  
Expression Patterns ◽  
Specific Expression ◽  
Genome Wide ◽  
Low Potassium ◽  
Duplication Events ◽  
Osmotic Balance ◽  
Short And Long Term ◽  
Low K

Abstract Potassium is one of the most essential inorganic cations for plant growth and development. The high affinity K+ (HAK)/K+ uptake (KUP)/K+ transporter (KT) family plays essential roles in the regulation of cellular K+ levels and the maintenance of osmotic balance. However, the roles of these genes in the responses of bananas to low-potassium stress are unclear. In this study, 24 HAK/KUP/KT (MaHAK) genes were identified from banana genomic data. These genes were further classified into four groups based on phylogenetic analysis, gene structure and conserved domain analysis. Segmental duplication events played an important role in the expansion of the MaHAK gene family. Transcriptome analysis revealed the expression patterns of MaHAKs in various tissues under different K+ conditions. MaHAK14b was upregulated under both short- and long-term K+-deficient conditions, suggesting that it plays crucial roles in K+ uptake at low K+ concentrations. Furthermore, MaHAK14b mediated K+ uptake when it was heterologously expressed in the yeast mutant R5421 on low K+ medium. Collectively, these findings provide a foundation for further functional analysis of MaHAK genes, which may be used to improve stress resistance in bananas.

Discordant aspects of aldosterone resistance in potassium depletion

1992 ◽  
Vol 262 (6) ◽  
pp. F972-F979 ◽  
Author(s):  
S. K. Mujais ◽  
Y. Chen ◽  
N. A. Nora
Keyword(s):  
Biochemical Response ◽  
Sprague Dawley ◽  
Short Term ◽  
Sprague Dawley Rats ◽  
Pump Activity ◽  
Before And After ◽  
Collecting Tubules ◽  
Low K ◽  
K Depletion

Aldosterone resistance, defined as absent kaliuretic response to exogenous hormone, has been described in K depletion. It is not clear whether the absent kaliuresis is due to activation of K-conserving mechanisms or to failure of activation of the Na-K pump in cortical collecting tubules (CCT) by mineralocorticoids. Adrenalectomized male Sprague-Dawley rats were allocated to either a normal or low-K diet. Na-K pump activity (pmol.mm-1.h-1) in microdissected CCT and medullary collecting tubules (MCT, inner stripe of the outer medulla) was determined at 7 or 21 days after allocation to the dietary groups before and after exogenous aldosterone (50 micrograms twice daily, for 3 days). K depletion led to progressive hypertrophic changes in the CCT and MCT manifest in an increase in basal Na-K pump activity. In both K repletion and short-term K depletion (7 days), aldosterone led to the expected increase in CCT Na-K pump activity. With long-term K depletion, the CCT Na-K pump response to aldosterone was blunted. In the MCT where under normal conditions the Na-K pump is aldosterone unresponsive, an increasing aberrant responsiveness to the mineralocorticoid was observed with progressive K depletion. We conclude that apparent aldosterone resistance in short-term K depletion is likely due to activation of K-conserving mechanisms with early preservation of the CCT biochemical response to the hormone. With long-term K depletion, a blunted biochemical response to aldosterone may contribute to the absent kaliuretic response. In the MCT, K depletion led to the development of aberrant responsiveness to aldosterone.

scholarly journals Long-term effect of no-tillage on soil organic matter fractions in rainfed Aragon (NE Spain) .

2014 ◽  
Vol 1 ◽  
Author(s):  
Nuria Blanco-Moure ◽  
Ana Bielsa ◽  
Ricardo Gracia ◽  
María Victoria López
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Agricultural Soils ◽  
Soil Surface ◽  
Term Effect ◽  
No Tillage ◽  
Long Term Effect ◽  
Organic Matter Fractions ◽  
Ne Spain

This paper assesses the long-term effect of no-tillage (NT) on soil organic carbon (OC) content and its distribution among different organic matter fractions in rainfed agrosystems of Aragón (NE Spain). Adjacent fields of NT, conventional tillage (CT) and natural soils (NAT) were compared in three different cereal production areas. In the soil surface, the higher OC content found in the NAT soils was due to the particulate organic matter. In the case of agricultural soils, in general, the fractions responsible for the OC increase under NT were the fine particulate organic matter and the mineral-associated organic matter occluded within stable microaggregates.

A long-term effect of subliminally presented words

2010 ◽  
Author(s):  
Andreas T. Breuer ◽  
Michael E. J. Masson ◽  
Glen E. Bodner
Keyword(s):  
Term Effect ◽  
Long Term Effect
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