1. During the daytime, the enzymatic activity of phosphorylase facilitates the conversion of starch into sugar, contributing to increased sugar levels.
2. Conversely, during the nighttime, there is a reversal in this process, with sugar being converted back into starch through the action of phosphorylase.
3. These diurnal variations in enzymatic activity result in dynamic changes in the osmotic potential of guard cells, influencing the regulation of stomatal aperture in plants.