Question

When stomata are opening; we observe which of the following changes in the guard cells?

• A. OP increase and TP decreases
• B. OP and TP increases
• C. OP decreases, TP increases
• D. OP and TP decreases

Answer 1

The correct option is A OP increase and TP decreases

DPD is diffusion pressure deficit. It is calculated by algebraic difference of osmotic pressure and turgor pressure. Water flows from a region of low DPD to a region of high DPD. Thus, any factor which increases DPD will favour movement of water into the cell.

During stomatal opening water moves into the guard cells and they swell and become turgid. This movement of water into the guard cells is made possible due to a an increase in DPD (increase in OP and decrease in TP).