chapter 30 4 l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Chapter 30.4 PowerPoint Presentation
Download Presentation
Chapter 30.4

Loading in 2 Seconds...

play fullscreen
1 / 9

Chapter 30.4 - PowerPoint PPT Presentation


  • 128 Views
  • Uploaded on

Chapter 30.4. How Do Stems and Leaves Conserve Water?. AP Biology Spring 2011. Water Loss. Most of water (>90%) absorbed by plant is lost due to evaporation out at the leaves Only a small amount of water is available to maintain the plants metabolism . Water-Conserving Cuticle.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Chapter 30.4' - deo


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
chapter 30 4

Chapter 30.4

How Do Stems and Leaves Conserve Water?

AP Biology

Spring 2011

water loss
Water Loss
  • Most of water (>90%) absorbed by plant is lost due to evaporation out at the leaves
  • Only a small amount of water is available to maintain the plants metabolism
water conserving cuticle
Water-Conserving Cuticle
  • Cuticle: translucent, water-impermeable layer of waxes, pectin, and cellulose fibers embedded in cutin
    • Secreted from epidermal cells which cover the outer surfaces of the plant
water conserving cuticle4
Water-Conserving Cuticle
  • Cuticle does not prevent sunlight from entering the leaf
  • Cuticle does restricts water loss, the inward diffusion of CO2, and outward diffusion of O2
controlled water loss of stomata
Controlled Water Loss of Stomata
  • Stomata: tiny, collapsible openings at the plant epidermis that regulate the passage of water, carbon dioxide, and oxygen
  • Guard Cells: a pair of these controls the opening and closing of the stomata
controlled water loss of stomata6
Controlled Water Loss of Stomata
  • Stomata open and close in response to environmental cues
    • Open stomata allow carbon dioxide to enter
      • BENEFIT
    • Open stomata allow water to be lost
      • DETRIMENT
controlled water loss of stomata7
Controlled Water Loss of Stomata
  • When plants are exposed to sunlight:
    • Potassium and water move into the guard cells
    • Causes guard cells to swell: Turgor Pressure
  • Stomata of most plants are open during the day and closed during the night
controlled water loss of stomata8
Controlled Water Loss of Stomata
  • CAM Plants
    • Cacti
    • Adaptations allow stomata to open at night when cells of these plants fix carbon dioxide
    • Stomata close during the day to conserve water in arid habitats
controlled water loss of stomata9
Controlled Water Loss of Stomata
  • Water-stessed plants close their stomata in response to abscisic acid
    • Absicsic acid: controls calcium ion entry into guard cells
  • Pollution:
    • Can clog stomata and damage them so that they remain permanently closed