Leaves structure and function By Bhuvan

Leaves Ask students to collect leaves and bring them to the class. Show them different leaves including simple and compound leaves. Let them touch and feel the texture. The teacher could also discuss venation.

Function of leaves Trap light energy for photosynthesis Producing sugar from photosynthesis Exchange of gases – oxygen and carbon dioxide

Structure Helps to catch more light energy Wide Helps to catch more light energy Thin Help get carbon dioxide from bottom to top of leaf for photosynthesis

Leaf structure Greener on top CO2 gets in here Teachers can supplement this by showing the students the onion peel under a microscope. CO2 gets in here

Leaf diagram – palisade layer Most chlorophyll Have a discussion with the students on the density of chlorophyll leading to photosynthesis. CO2

Leaf cell - palisade Position? Upper surface of leaf Features? Box shape Chloroplasts Function? Photosynthesis

Stoma is a small hole Its size is controlled by 2 guard cells closed open

Gas exchange Leaves are designed to allow carbon dioxide to get to the main chlorophyll layer at the top of the leaf They have small holes called stomata on the under surface Each hole is open & closed by 2 guard cells

Leaf diagram – stoma and guard cells

Stoma position

Stoma function is for gas exchange in the leaf oxygen Guard cell Provided plant is photosynthesising Carbon dioxide

Stomata open and close at different times of the day When it is light the plant needs CO2 for photosynthesis so the stoma open At night (darkness) they close

Gas exchange

T S of stem

The End