1. Leaf Structure Aquaponics

3. Leaf Structure-Dermal layers Cuticle-The thin waxy covering on the outer surface of the leaf has a thin waxy covering This layer's primary function is to prevent water loss within the leaf. (Plants that live entirely within water do not have a cuticle). Directly underneath the cuticle is a layer of cells called the epidermis (upper and lower)

4. Leaf Tissues Mesophyll – Ground tissue between upper and lower epidermis – Two types: Palisade parenchyma (mesophyll) cells – Lots of chloroplasts in these cells – Most photosynthesis occurs here Spongy parenchyma (mesophyll) cells – Lots of air spaces where O 2 and CO 2 circulate – Near stomata (Think: sponges have lots of air spaces) Veins – Xylem and phloem are continuous from roots through stem to leaves

6. Vascular Tissue Transports materials in roots, stems, & leaves. Xylem – Carry water & minerals up from roots – Tube-shaped dead cells Their walls are used as water pipes Phloem – Carry nutrients (food) throughout plant SUGARS (sucrose), amino acids…. – Tube-shaped living cells

8. http://wps.prenhall.com/wps/media/objects/838/858365/ch03anim/3_1_6_1a.swf

10. Stomata and Guard Cells The underside portion of a leaf has stomata and is the site of transpiration (water movement) and gas exchange.

11. Stomata help regulate the rate of transpiration Guard cells – 2 cells on either side of stomata (surrounds stomata) – regulate water loss What conditions will promote closing of guard cells? – Hot, dry, windy conditions

12. Stoma Opening/Closing http://academic.kellogg.edu/herbrandsonc/bio111/animations/0021.swf

13. Vein  H2O Leaf cross section Figure 10.3 Mesophyll (leaf tissue) CO 2 O2O2 Stomata CO2 O2 Stomata; Stoma (pl) 30-40 chloroplasts Cross Section

14. http://www.purchon.com/biology/flash/leaf.swf