Plant Organ (Dicotyledonous Leaf)

Front 1

Main functions of leaves

Back 1

•trap sunlight for photosynthesis

•allows gaseous exchange to take place through the stoma for photosynthesis ,respiration and transpiration

•transport water and produced nutrients

Front 2

External structure of a leaf

Back 2

1.Lamina/leaf blade :has large, flat surface for absorbing lots of sunlight for photosynthesis

2. Midrib/main vein: with xylem to conduct water and dissolved mineral salts and phloem tissues to conduct dissolved nutrients (sugars)

3.margin-the edge of the leaf

4. Petiole/the leaf stalk:supports the leaf,has xylem and phloem to conduct water to and dissolved nutrients from ,the leaf.

5. Lateral veins: support the lead blade in a flat position to get lots of sunlight for photosynthesis

Front 3

Internal structure of a leaf (epidermis)

Back 3

•cuticle is impermeable to water and is transparent -prevents moisture loss and allows sunlight through to the mesophyll cells

•upper epidermal cells are transparent -allow sunlight through to the mesophyll cells and also has no chloroplasts

•lower epidermis has many stoma -ensures that gaseous exchange takes place

Front 4

Palisade and Spongy Mesophyll

Back 4

Palisade mesophyll

-directly below the upper epidermis with no intercellular spaces to have a large possible surface exposed to sunlight

-chlorenchyma tissues for photosynthesis

-thin cell walls to facilitate osmosis and diffusion of gases

Spongy mesophyll

-loosely packed for gaseous exchange

-chlorenchyma for photosynthesis

Front 5

Vascular bundles

Back 5

•contain xylem:

to transport water and dissolved mineral salts to the mesophyll cells

•contain phloem:

To transport produced organic nutrients to other parts of the plants