Opening and closing stoma, animation. Stomata are pores found on the leaf surface that regulate the exchange of gases between the leaf's interior and the atmosphere. Each pore is controlled by two guard cells (white). First potassium ions (black) are seen being actively pumped from the epidermal cells (brown) to the guard cells. This raises the osmotic pressure, and water (blue) moves into the cells. This causes a turgor state that leads to the guard cells swelling. The thick central walls don't stretch as much as the thinner outer walls, pulling the pore open. Closing of the pore occurs when potassium ions diffuse out of the guard cells, followed by water, causing the cells to become flaccid. Stomatal closure is a natural response to darkness or drought as a means of conserving water. | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Biocosmos / Francis Leroy & Maximilien Moens |
Modell-Rechte: | nicht erforderlich |
Länge: | 35 Sekunden |
Seitenverhältnis: | 16:9 |
Restrictions: | - |