1. Gas Exchange in Plants
SBI 3U

2. Plants need Oxygen too.
• Plants obtain the
gases they need
through their leaves.
• They require oxygen
for respiration and
carbon dioxide for
photosynthesis.
http://www.chemsoc.org/networks/LearnNet/cfb/images/12A.jpg

3. The gases diffuse into the
intercellular spaces of the
leaf through pores, which
are normally on the
underside of the leaf –
stomata. From these
spaces they will diffuse
into the cells that require
them.
The Epidermis of a leaf.

4. http://virtual.yosemite.cc.ca.us/randerson/Lynn's%20Bioslides/27.jpg
Stomatal opening and closing depends on changes in
the turgor of the guard cells. When water flows into the
guard cells by osmosis, their turgor increases and they
expand. If the guard cells loose water the opposite
happens and the pore closes.

5. http://biology.unlv.edu/Schulte/Anatomy/Leaves/PopulusStomata.jpg

6. http://www.plantsci.cam.ac.uk/Webb/images/stomata.jpg

7. http://bio1151.nicerweb.com/Locked/me
dia/ch36/36_15GuardCellFunction.jpg

8. http://www.progressivegardens.com/knowledge_tree/stomata.jpg

9. Lenticels – pores in the bark of
stems
http://sciencecity.oupchina.com.hk/biology/student/glossary/img/l
enticels.jpg
http://www.treedictionary.com/DICT200
3/IMAGES/LENTICELS%20BIRCH.jpg

10. http://www.digitalfrog.com/resources/archives/leaf.jpg
http://www.biotopics.co.uk/plants/leafst.html

12. http://home.comcast.net/~john.kimball1/BiologyPages/S/stoma.gif

13. http://www.northern.edu/ramsayj/etechWeb/images/leaves/leaf%20example1%20copy.JPG

15. Transport in plants
SBI 3U

17. http://www.bbc.co.uk/schools/gcsebitesize/img/bixylemphloem.gif