The Leaf

Lamina

The leaf blade which is usually broad and flat to increase the surface area for maximum sunlight absorption

Why is the thin shape of the lamina important for photosynthesis?

It allows sunlight to penetrate the layers of the leaf and provides a shorter diffusion distance for carbon dioxide to enter the leaf and the oxygen to exit

What does the network of veins along the lamina contain?

Vascular Bundles which consist of xyl vessels and phloem tubes

What is the function of the xylem vessels?

To transport water from the roots to the leaves

What is the function of the phloem tubes?

To transport the plant’s food (glucose) to other parts of the plant

What is the main vein in a leaf and where does it run

The midrib is continuous with the petiole and runs through the center of the leaf.

What is the main vein’s function?

To support the leaf

Petiole

The leaf stalk

What is the function of the petiole

Attaches the leaf to the plant and produces support for the leaf. It keeps the leaves at 90° angles for full exposure to sunlight

Why are most leaves green?

They contain chlorophyll

What is chlorophyll

A green pigment found in the chloroplasts of plant cells

What is the function of chlorophyll?

To trap sunlight energy and convert it to chemical energy to be used in photosynthesis

What are leaf margins?

The edges of leaves

How can leaf margins vary?

They can be smooth or serrated and become narrow at the tip (apex) opposite the petiole

Cuticle

A waxy covering on the upper and lower surface

Epidermal cells

The outermost cells of a leaf that contain no chloroplasts

Stoma

A pore on the underside of the leaf through which carbon dioxide enters and oxygen exits

What happens when stomata are open

Water will escape the leaf resulting in dehydration

Stomata are usually found on which surface?

Lower surface

Guard Cells

A pair of sausage-shaped cells found on either side of the stomata.

Mesophyll cells

Specialized cells that contain chloroplasts . Consists of palisade cells and spongy cells.

Palisade cells

Contain more chloroplasts as they are the main site of photosynthesis

What do Air spaces allow?

Between the spongy cells, allow for diffusion of gases in and out of the leaf

What is the function of the Vein

Provides support for the leaf. It transports both water and minerals (via xylem) from the roots to the leaves and transports manufactured food, glucose, (via phloem) from the leaves to all parts of the plant.

What is the function if the Waxy Cuticle

prevents water loss