Any of the microscopic openings or pores in the epidermis of leaves and young stems. They are generally more numerous on the undersides of leaves. They provide for the exchange of gases between the outside air and the interconnecting air canals within the leaf. A stoma opens and closes in response to turgor pressure within its two surrounding guard cells. Because the inner wall of each of these sausage- or bean-shaped cells is thicker than the outer wall, when they fill with water and become turgid they balloon outward, enlarging the stoma. A drop in carbon-dioxide levels to lower than normal also causes the guard cells to become turgid. Guard cells control excessive water loss from the plant, closing on hot, dry, or windy days and opening when conditions are more favorable.
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Practical aspects of stoma management: by reading this article and writing a practice profile, you can gain ten continuing education points (CEPs). You have up to a year to send in your practice profile. Guidelines on how to write and submit a profile are featured at the end of this article. (Gastroenterology).
Nov 06, 2002; NS165 Collett K (2002) Practical aspects of stoma management. Nursing Standard. 17, 8, 45-52. Date of acceptance: October 16,...