Question

How do guard cells regulate the opening of stomatal pores?

Answer 1

Guard cells regulate the opening of the stomatal pores by controlling their internal water pressure (turgor pressure).

• When water from surrounding epidermal cells flows into the guard cells, the guard cells swell and become fully turgid.
• Because the guard cells have thin, elastic outer walls and thick, rigid inner walls, the swelling causes the outer walls to bulge outward.
• This outward expansion pulls the thick inner walls apart, creating an opening and successfully opening the stomatal pore.