2.5.10

Stages of Stomata

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State of Stomata

The state of stomata (open or closed) achieves a balance between allowing gases for photosynthesis into the leaves, and conserving water in the plant.

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Abundant water

  • When water is abundant (lots available) the plant can afford to lose water.
  • So it opens the stomata to allow gases for photosynthesis to move freely in and out of the leaf.
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Scarce water

  • When water is scarce (rare), stomata close in order to prevent further water loss.
    • This is achieved by guard cells returning to a limp state after they lose water.
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Time of day

  • At night, stomata close because, in the absence of sunlight, carbon dioxide is not required for photosynthesis.
    • At this time, their only objective is to prevent water loss.

Jump to other topics

1Cell Biology

1.1What's in Cells?

1.2Cell Division

1.3Transport in Cells

2Organisation

2.1Principles of Organisation

2.2Enzymes

2.3Circulatory System

2.4Non-Communicable Diseases

2.5Plant Tissues, Organs & Systems

3Infection & Response

4Bioenergetics

5Homeostasis & Response

5.1Homeostasis

5.2The Human Nervous System

5.3Hormonal Coordination in Humans

5.4Plant Hormones

6Inheritance, Variation & Evolution

7Ecology

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