scholarly journals Sodium and Potassium Uptake by Seedlings of Hordeum Vulgare

1965 ◽  
Vol 18 (1) ◽  
pp. 10 ◽  
Author(s):  
MG Pitman
Keyword(s):  
Hordeum Vulgare ◽  
Water Flow ◽  
Divalent Cations ◽  
Potassium Transport ◽  
Potassium Uptake ◽  
Active Process ◽  
Experimental Conditions ◽  
Sodium Uptake ◽  
Sodium And Potassium

Uptake of potassium and sodium from culture solutions by barley seedlings under a range of experimental conditions has been determined. It was shown that both sodium and potassium transport to the shoot was due to an active process in the root which was limited by the plant's growth. This process was not available for uptake of divalent cations. Sodium uptake at higher concentrations showed some relation to transpiration and the resulting increase in sodium uptake with concentration reduced the selectivity in the plant for potassium to sodium. It was shown that potassium transport across the root was independent of water flow to the cytoplasm. The role of the cytoplasm in selective ion uptake to the shoot is discussed.

scholarly journals Transpiration and the Selective Uptake of Potassium by Barley Seedlings (Hordeum Vulgare Cv. Bolivia)

1965 ◽  
Vol 18 (5) ◽  
pp. 987 ◽  
Author(s):  
MG Pitman
Keyword(s):  
Hordeum Vulgare ◽  
Active Transport ◽  
Transpiration Rate ◽  
Water Flux ◽  
Anion Transport ◽  
Potassium Uptake ◽  
Sodium Uptake ◽  
Total Uptake ◽  
Sodium And Potassium ◽  
Active Anion

Selective potassium uptake by barley seedlings decreases with increased solution concentrations above 20 m-equiv /1. This decrease is shown to be due to an action of transpiration. Total uptake of potassium and sodium was unaffected by transpiration, but increased transpiration rate increased sodium uptake and decreased potassium uptake. These changes in sodium and potassium content are difficult to explain in terms of "passive" metabolic components of uptake. It is suggested that sodium and potassium uptake to the shoot is controlled by active anion transport and that water flux acts on movement of sodium and potassium through the root to the site of active transport.

scholarly journals Plant Response to Saline Substrates II. Chloride, Sodium, and Potassium Uptake and Translocation in Young Plants of Hordeum Vulgare During and After a Short Sodium Chloride Treatment

1962 ◽  
Vol 15 (1) ◽  
pp. 39 ◽  
Author(s):  
H Greenway
Keyword(s):  
Sodium Chloride ◽  
Hordeum Vulgare ◽  
Salinity Stress ◽  
Chloride Concentration ◽  
Plant Response ◽  
Potassium Uptake ◽  
Sodium Chloride Concentration ◽  
Subsequent Response ◽  
Chloride Treatment ◽  
Sodium And Potassium

Young barley plants, Hordeum vulgare cv. Chevron, were subjected to a sodium chloride concentration of 100 m-equiv/l. In a "continued" treatment, the salinity stress was maintained for 15 days. In a "removed" treatment, sodium chloride was removed from the substrate after 5 days, and the subsequent response was studied over a period of 10 days.

Renal Na-K-ATPase: its role in tubular sodium and potassium transport

1982 ◽  
Vol 242 (3) ◽  
pp. F207-F219 ◽  
Author(s):  
A. I. Katz
Keyword(s):  
Cation Transport ◽  
Potassium Transport ◽  
Secondary Active Transport ◽  
Nephron Segments ◽  
Single Nephron ◽  
Acute Changes ◽  
K Transport ◽  
Sodium And Potassium ◽  
Slow Turnover

Na-K-ATPase, the enzymatic equivalent of the sodium:potassium pump, is found in large amounts in the kidney, and this organ has figured prominently both as a source for the purification of the enzyme and as a target for the study of its properties. Located on the basolateral aspect of tubule cells, renal Na-K-ATPase plays a key role in the active translocation of Na and K across this membrane as well as in the "secondary active" transport of a number of other solutes. The activity of renal Na-K-ATPase varies in parallel with sustained changes in Na or K transport, indicating the participation of this enzyme in the chronic adaptation of the kidney to altered Na reabsorption or K secretory load. Because of its slow turnover, however, the role of Na-K-ATPase in the modulation of acute changes in cation transport is unclear. Several hormones and vanadate influence renal Na-K-ATPase activity, and their importance as potential physiologic regulators of this enzyme is examined. Most of the information on the renal enzyme has been obtained from studies using homogenates or subcellular fractions thereof, but more recently the development of tubule microdissection and microanalytic methods has made possible the study of Na-K-ATPase in single nephron segments. This approach has opened new possibilities for evaluating the role of this enzyme in kidney function by facilitating correlation of enzyme activity with transport events in the same structure and by enabling us to focus the study of Na-K-ATPase on discrete anatomic subdivisions of the functionally heterogeneous nephron.

Sodium and potassium handling by the aldosterone-sensitive distal nephron: the pivotal role of the distal and connecting tubule

2004 ◽  
Vol 287 (4) ◽  
pp. F593-F601 ◽  
Author(s):  
Pierre Meneton ◽  
Johannes Loffing ◽  
David G. Warnock
Keyword(s):  
Sodium Intake ◽  
Collecting Duct ◽  
Genetic Defect ◽  
Potassium Transport ◽  
The Body ◽  
Dietary Sodium ◽  
Sodium Reabsorption ◽  
Connecting Tubule ◽  
Sodium And Potassium

Sodium reabsorption and potassium secretion in the distal convoluted tubule and in the connecting tubule can maintain the homeostasis of the body, especially when dietary sodium intake is high and potassium intake is low. Under these conditions, a large proportion of the aldosterone-regulated sodium and potassium transport would occur in these nephron segments before the tubular fluid reaches the collecting duct. The differences between these two segments and the collecting duct would be more quantitative than qualitative. The collecting duct would come into play when the upstream segments are overloaded by a primary genetic defect that affects sodium and/or potassium transport or by a diet that is exceedingly poor in sodium and rich in potassium. It is likely that the homeostatic role of the distal convoluted and connecting tubules, which are technically difficult to study, has been underestimated, whereas the role of the more easily accessible collecting duct may have been overemphasized.

Site of Lysosome Production During Hepatic Injury

1969 ◽  
Vol 27 ◽  
pp. 348-349
Author(s):  
Nalin J. Unakar
Keyword(s):  
Electron Microscopy ◽  
Golgi Apparatus ◽  
Mouse Liver ◽  
Hepatic Injury ◽  
Close Approximation ◽  
Experimental Conditions ◽  
Toxic Injury

The increased number of lysosomes as well as the close approximation of lysosomes to the Golgi apparatus in tissue under variety of experimental conditions is commonly observed. These observations suggest Golgi involvement in lysosomal production. The role of the Golgi apparatus in the production of lysosomes in mouse liver was studied by electron microscopy of liver following toxic injury by CCI4.

The Affiliative Role of Empathy in Everyday Interpersonal Interactions

2019 ◽  
Author(s):  
Whitney R. Ringwald ◽  
Aidan G.C. Wright
Keyword(s):  
Individual Differences ◽  
Structural Equation ◽  
Community Sample ◽  
Empirical Support ◽  
Interpersonal Behavior ◽  
Equation Modeling ◽  
Experimental Conditions ◽  
Student Sample ◽  
Ecological Momentary

Empathy theoretically serves an affiliative interpersonal function by satisfying motives for intimacy and union with others. Accordingly, empathy is expected to vary depending on the situation. Inconsistent empirical support for empathy’s affiliative role may be due to methodology focused on individual differences in empathy or differences between controlled experimental conditions, which fail to capture its dynamic and interpersonal nature. To address these shortcomings, we used ecological momentary assessment to establish typical patterns of empathy across everyday interactions. Associations among empathy, affect, and interpersonal behavior of self and interaction partner were examined in a student sample (N=330), then replicated in a pre-registered community sample (N=279). Multi-level structural equation modeling was used to distinguish individual differences in empathy from interaction-level effects. Results show people are more empathetic during positively-valanced interactions with others perceived as warm and when expressing warmth. By confirming the typically affiliative role of empathy, existing research to the contrary can be best understood as exceptions to the norm.

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