2 3 16 Perform A First Hand Investigation To Gather Informat

Method 1:
- Looked at Acacia pycnantha plant
- Phyllodes instead of leaves to reduce water loss through transpiration
- Looked at an eucalyptus leaf
- Thick waxy cuticle
- Water drop on the leaf surface stays together
- Reflective leaf surface
- Woody petiole
- Leaf orientation on the tree

Method 2:
- 4 measuring cylinders were filled with water to the top graduation, and some paraffin oil added to each, to form a visible surface layer
- One plant was placed into the first measuring cylinder, with leaves protruding from the top.
- Similarly, the lower epidermis of the 2nd plant was smeared with petroleum jelly, and then placed in the 2nd measuring cylinder. The upper epidermis of the 3rd plant was smeared with petroleum jelly, and both sides of the 4th plant were smeared with petroleum jelly.
- The measuring cylinders with plants were weighed.
- After 24 hours, they were reweighed, and any difference in weights recorded.

Results:
- Untreated (control) plant had most water loss, followed by upper epidermis covered, lower epidermis covered, and both sides covered.
- This suggests that plants lose water through their stomates, and that leaves have more stomates on their underside. This is because stomates on the underside of a leaf are less exposed to the sun than stomates on the upper epidermis, so having stomates on the underside of a leaf minimises water loss by evaporation.

General Response
Eucalyptus
- Waxy, hard leaves: Reduces water loss by reducing the rate of transpiration from the leave surface
- The leaves hang vertically, and this reduces the water loss, conserving water

Banksia
- Leaves have sunken stomates – this reduces transpiration

Wattle
- Leaves are small and hairy – the small size means less evaporation of water, and the hairy leaves reduce the transpiration by trapping water.

Grevillia
- Plants have narrow leaves to reduce the surface area, reducing transpiration