Stomatal opening and closing in commelina communis
Produced by Science & Plants for Schools (SAPS), this investigation looks at stomatal opening and closing in Commelina communis (Asiatic dayflower). This is achieved by varying the turgor of the guard cells by bathing lower epidermal peels in solutions of different osmotic strengths. Changes in guard cell turgor results in changes to the size of the stomata.
The experiment can be used to:
• practice the use of an eye-piece graticule
• develop good microscope skills
• develop knowledge and understanding of how osmosis and the state of turgor in guard cells affects the opening and closing of stomata.
The investigation is designed for students following a Scottish Highers course but it is equally useful for other post-16 courses in biology. It could even be adapted for secondary students of a younger age.