Induction of Cell Division in Leaf Cells of Coconut Palm by Alteration of pH and its Correlation with Glyoxalase-I Activity

Cell division in suspension cultures obtained from leaf cells of coconut was influenced by pH of the culture media. A 3-fold increase in cell number was obtained at pH 7.0 compared to suspensions growing at pH 5.0. The pH of both cells and media changed after 48 h of growth. Internal cell pH showed a significant increase when cultures were grown at pH 7.0 and 8.0 and increased only slightly at pH 5.0 and 6.0. Glyoxalase-I activity of cells in suspension culture was found to be pH-depcndent, showing maximum activity at pH 7.0. Glutathione, a co-enzyme for the substrate methylglyoxaJ for glyoxalase-I, produced a 2-fold increase in cell number at a concentration of 5 × 10−3 mol dm −3. The polyamine, spermidine, promoted cell division maximally at a concentration of 10−6 mol dm−3. Methylglyoxal-bis (guanylhydrazone), an inhibitor of spermidine biosynthesis, strongly inhibited cell division giving maximum inhibition at a concentration of 3 × 10−6 mol dm −3. These results indicate a positive correlation between cell division and glyoxalase-I activity.