Rucete ✏ Biology In a Nutshell
1. Function of Stomata
Stomata are small pores on leaf surfaces that regulate gas exchange, transpiration, ascent of sap, and photosynthesis.
Each stoma is surrounded by guard cells, which control the opening and closing of the pore.
2. Factors That Cause Stomata to Open
Low CO₂ concentration inside the leaf
→ Encourages stomata to open to allow more CO₂ in for photosynthesis.Influx of potassium ions (K⁺) into guard cells
→ Causes water to enter by osmosis, making guard cells turgid and opening the pore.Daylight
→ During the day, CO₂ levels drop due to active photosynthesis, triggering stomatal opening.
3. Factors That Cause Stomata to Close
High temperatures
→ Helps reduce water loss by minimizing transpiration.Nighttime
→ CO₂ levels rise due to respiration, causing stomata to close since photosynthesis is inactive.