BIO 1306 Lecture Notes - Lecture 16: Circadian Rhythm, Stoma, Transpiration
Document Summary
Concept 36. 4: the rate of transpiration is regulated by stomata. Leaves generally have large surface areas and high surface-to-volume ratios. These characteristics increase photosynthesis, but also increase water loss through stomata. Guard cells help balance ________________ with gas exchange for photosynthesis. About 95% of the water a plant loses escapes through stomata. Each stoma is flanked by a pair of guard cells, which control the diameter of the stoma by changing shape. Stomatal density is under genetic and ________________ control. Changes in turgor pressure open and close stomata. When turgid, guard cells bow outward and the pore between them opens. When flaccid, guard cells become less bowed and the pore closes. This results primarily from the reversible uptake and loss of potassium ions (k. Generally, stomata open during the day and close at ________________ water loss. All eukaryotic organisms have internal clocks; circadian rhythms are 24-hour cycles. Drought, high temperature, and wind can cause stomata to close during the daytime.
