Definition - What does Guard Cell mean?
A guard cell is an epidermal cell that can open the stomata to take in or release oxygen, carbon dioxide and water, consequently enabling these molecules to travel through the stomata. Guard cells are shaped like kidneys or sausages and the walls normally vary in rigidity.
MaximumYield explains Guard Cell
Guard cells are normally produced in pairs that are divided by the stomata's pore. The pores widen when water flows freely, but the guard cells tend to become weak and flaccid if the plant is lacking water. Sunrise encourages a flow of potassium ions through the guard cells, which stimulates water movement.
Guard cells are often affected by endogenous and environmental factors including drought, temperature, humidity, concentration of carbon dioxide, and light. Guard cells can also process and perceive changes in the plant’s hormonal structure.