Transpiration and the leaf
Edited by Jamie (ScienceAid Editor), SpellBot, Taylor (ScienceAid Editor)
Below is a cross section of a leaf. This is what you would see if you looked down the leaf towards the stem.
The guard cells control the entry of carbon dioxide through the stomata by opening and closing. Therefore they close at night - reducing water loss.
- 1Shape.The long, thin shape of the leaf provides maximum surface area for receiving light.Advertisement
- 2Cuticle.The waxy cuticle on the top of the leaf protects it from the elements and also prevents water from escaping.
- 3Palisade layer.Cells have a lot of chloroplasts (containing chlorophyll) in them - making the most of the conditions high in light on the top of the leaf.
- 4Veins.Phloem carry sugar and amino acids, and xylem carry water and mineral ions from the roots.
For more information on this subject see water in plants.
Transpiration is the movement of water molecules through the plant - up from the roots, through Xylem vessels and evaporating out through the stomata in the leaves.
Certain conditions affect the rate of transpiration.
- 1Temperature.If it is warm, water is lost because of the increased movement of the molecules.
- 2Wind Velocity.The wind will blow away molecules near the stomata.
- 3Humidity.Moisture in the air will slow down water loss because the concentration gradient is small.Advertisement
- If you have problems with any of these steps, ask a question for more help, or post in the comments section below.
Categories : Plants
Recent edits by: SpellBot, Jamie (ScienceAid Editor)