ISSN:
1365-3040
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Summary. Soluble potassium concentrations were determined for the slightly vacuolated, unicellular, walled alga Chlorella emersonii. Sap of cells grown in 1 mol m−3 NaCI contained 140 mol m−3 K+ and sap of cells grown in 125, 200, and 335 mol m−3 NaCI contained 160-180 mol m−3 K +.The possible regulation of K + concentrations by a system of lurgor and volume maintenance was investigated by supplying 3-0-methylglucose. This solute accumulates to 85-230 mol m−3 in C. emersonii, but is not metabolized. Accumulation of 3-0-methylglucose increased the volume of cells grown at both low and high NaCI by about 10%. Furthermore, accumulation of 3-0-methylglucose also increased turgor pressures of cells grown in 1 and 125 mol m−3 NaCI by 0.3 and 0.2 MPa, respectively. (Similar measurements were not attempted for cells grown in 200 and 335 mol m−3 NaCI, because of the insensitivity of available methods to measure turgor pressure of cells exposed to high external osmotic pressures.)At all NaCI concentrations, the K + concentrations of cells which had accumulated 3-0-methylglucose were only 10-20 mol m−3 lower than K+ in cells which had not been supplied with 3-0-methylglucose. In contrast, accumulation of 3-0-methylglucose greatly decreased concentrations of the endogenous osmotic solutes, proline and sucrose, which accumulated in cells grown in 125 mol m−3 and higher NaCI concentrations.It is concluded that K+ concentrations in Chlorella emersonii are not controlled by a system of turgor and volume maintenance.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-3040.1983.tb01272.x
