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 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 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.

scholarly journals Uptake of Potassium and Sodium by Seedlings of Sinapis Alba

1966 ◽  
Vol 19 (2) ◽  
pp. 257 ◽  
Author(s):  
MG Pitman
Keyword(s):  
Plant Growth ◽  
General Model ◽  
Cell Walls ◽  
Sinapis Alba ◽  
Anion Transport ◽  
Sodium Uptake ◽  
Lower Ratio ◽  
Total Potassium ◽  
Different Levels ◽  
Active Anion

Seedlings of Sinapis alba (mustard) have a lower potassium selectivity than those of barley, as shown by the lower ratio of potassium to sodium in the shoots of plants grown on the same solution. The ratio in the shoots is usually lower than in the roots, whereas in barley it is higher. In spite of this difference in selectivity, the uptake of potassium and sodium by mustard has much in common with that by barley. The total potassium and sodium uptake to the shoot is independent of the ratio in the solution; the ratio of potassium to sodium in the shoot is proportional to that in the roots, but not to that in solution; and potassium selectivity can be reduced by transpiration. Thus it appears that the same general model for ion uptake can be used for both plants, although they have different levels of selectivity. In this model it is suggested that total potassium and sodium uptake is controlled by an active anion transport coupled with plant growth by means of metabolism, but selectivity is determined during movement of ions into the stele through cytoplasm and cell walls.

scholarly journals Active transport of sodium and potassium by the choroid plexus of the rat

1974 ◽  
Vol 241 (2) ◽  
pp. 359-372 ◽  
Author(s):  
Conrad E. Johanson ◽  
Donal J. Reed ◽  
Dixon M. Woodbury
Keyword(s):  
Choroid Plexus ◽  
Active Transport ◽  
Sodium And Potassium

Sodium and potassium movement in the excised rat aorta

1960 ◽  
Vol 199 (1) ◽  
pp. 28-30 ◽  
Author(s):  
Oswald Dawkins ◽  
David F. Bohr
Keyword(s):  
Cell Membrane ◽  
Active Transport ◽  
Rat Aorta ◽  
Rat Plasma ◽  
Electrolyte Composition ◽  
Krebs Solution ◽  
Equivalent Amount ◽  
Rapid Changes ◽  
Active Transport System ◽  
Sodium And Potassium

When the rat aorta is excised and placed in a bath of Krebs' solution it loses over two-thirds of its potassium and gains roughly an equivalent amount of sodium within the first 15 seconds. If the aorta is placed in rat plasma instead of Krebs' solution, a similar change occurs. These rapid changes in aorta electrolyte composition do not occur when the whole rat is perfused with Krebs' solution. It is concluded that in the handling involved in the removal of the aorta its cell membrane barriers are altered in such a way that they no longer maintain the normal transmembrane gradients of these cations. After 2 minutes in the bath the potassium in the aorta gradually increases and its sodium decreases suggesting that the cell membrane has regained its characteristics as a barrier and is capable of maintaining sodium and potassium gradients established by an active transport system.

Sign in / Sign up

Export Citation Format

Share Document