Preferential Absorption of Potassium by Leaf Tissue of the Mangrove, Avicennia Marina: An Aspect of Halophytic Competence in Coping with Salt

Abstract

SummaryOne aspect of the salt tolerance of the mangrove, Avicennia marina, was investigated: the preferential absorption of potassium by leaf tissue in the presence of high concentrations of salt (sodium chloride). The rate of absorption of potassium, over the concentration range 0·02 to 1·5 mM, follows the Michaelis-Menten relation, approaching the theoretical maximum, V max, at 1· 5 mM. The apparent Michaelis constant is 0·20 mM. At higher concentrations, up to 50 mM potassium, the rate of potassium absorption reaches values several times higher than the theoretical maximum calculated on the basis of the relation applying over the low range of concentrations, indicating the operation of a second mechanism of absorption. At both low (1 mM) and high (10 mM) concentrations of potassium, its absorption was little affected by sodium chloride concentrations up to 200 mM. At 10 mM potassium, sodium chloride at concentrations up to and including 500 mM (more than its concentration in sea.water) failed to interfere with the absorption of potassium.~,,~,

Sodium and Potassium Absorption by Bean Stem Tissue

“…6) (2). This is true for barley roots (4), corn roots (35), mangrove leaves (26), and storage tissue (21). In fact this ;m has been dual pattern seems to-be universal in plant cells (2).…”

“…Although the use o,f 86Rb as a tracer for K has been questioned in uptake studies involving marine algae (37) there was little qualitative or quan,itative difference in results when 86Rb or 42K was used to label K solution's. In uptake studies with higher green plants use of 8)Rb to label K appears to be a valid procedure and is well documented (23,26). Since relatively little is known about the albsorpti-on characteristics of stem tissue, however, it seemed advisable to test the validity of such a procedure.…”

Kinetics and Energetics of Light-enhanced Potassium Absorption by Corn Leaf Tissue

“…The demonstration of more than 1 ion-transport mechanism in higher plants (6,7,30,31) light is closely linked to ATP formed by cyclic photophoslphorylation (22,23,29). Cyanide and unoouplers of oxidative phosphorylation, DNP, mC4-CCP, or NaN3 (1,11,12,18,19,32), manifested their greatest effect in the dark when a large percenitage of ATP is probably formed by respiratory processes.…”

Interactions between Ca, Na, and K inSalicornia virginicaand barley roots under saline conditions: multi- compartment transport box experiment

“…As far as we know, however, there has been little information on the stimulation of K uptake by Na in halophytes. Some halophytes, like Avicennia marina (Rains and Epstein 1967) and Triglochin maritima (Jefferies 1973) respond to salinity by increasing the K uptake in the presence of Ca. However, Suaeda maritima showed an uptake of K basically similar to that of the typical glycophyte pattern (Flowers et al 1977).…”