Uptake of magnesium by suspension cultures of plant cells (Ipomoea sp.)

Abstract

The magnesium level required to support full growth in batch suspension cultures of an Ipomoea sp. (Morning Glory) cell line in 2% sucrose media was less than 0.3 mM. The uptake of magnesium increased with increasing magnesium in the medium, and with increasing pH at constant magnesium level. In medium containing 1.0 mM (24 mg/ℓ) magnesium, a culture kept at pH 4.7 absorbed 6 mg of magnesium in 150 h; the corresponding figure for a culture kept at pH 6.9 was 19 mg.Much of the excess magnesium taken up by cells grown at the 1.0 mM magnesium level at various controlled pH levels could be extracted by grinding the cells in distilled water. The data suggest that under conditions of high magnesium supply and high pH these cells absorb large amounts (i.e. several milligrams per gram dry cells) of magnesium in excess of their requirement for growth.