• NAME :FAIMA NAZIR• ROLL NO: 11031506-040• DISCIPLINE: BS(HONS)BOTANY• SEMESTER: 6th• COURSE TITLE: PLANT ANATOMY• COURSE CODE: BOT-307• SUBMITTED TO: M’AM TAYBA

• U O G

TOPIC

ANATOMY OF LEAVES

TYPES OF LEAVES

There are two types of leaves1. Dorsilventral

leaves(dicotyledonous)2. Isobilatral

leaves(monocotyledonous)

ANATOMY OF DICOTYLEDONOUS LEAF

A leaf consists of following layers.1. Cuticle2. Upper epidermis 3. Lower epidermis4. Pores also known as stoma /stomata5. Mesophyll Tissue 1.Palisade mesophyll 2.Spongy mesophyll

CUTICAL

1. The outer thick waxy covering of the plants and leaves.

2. Cuticle protects plant from drying out by reducing water loss.

3. Does not let oxygen or carbon dioxide pass through it.

UPPER EPIDERMIS

• Upper epidermis consists of a single layer of cells covered by cuticle. Sometime contains pores which allow gas or water molecule to pass through it.

LOWER EPIDERMIS

• Below the spongy mesophyll is the lower epidermis. We will see vascular bundle here and stomata.

STOMATA

• The pore like openings in the underside of the leaf is called stoma (singular) and stomata (plural).

• Each stoma consists of two guard cells which control the opening and closing of the stomata

FUNCTION OF STOMATA

• Stomata allow carbon dioxide and oxygen and water vapor diffuse into and out of the leaf by opening and closing .

• If the stomata were kept open all the time, water loss due to transpiration would be so great that few plants would be able to take enough water to survive.

MESOPHYLL TISSUE

• There are two type of mesophyll tissue

1.Palisade mesophyll• Just beneath the epidermis there are column

shaped cells containing chloroplast are known as Palisade mesophyll .

• Most photosynthesis takes place here.

2. Spongy mesophyll• The second type of mesophyll tissue is the

spongy mesophyll which is composed of closely packed irregular shape cells surronded by air spaces.

• There are fewer chloroplast because they are under side of the leaves

ANATOMY OF MONOCOTYLEDONOUS LEAF

• Most of monocotyledonous leaves are nearly erect and more or less both surfaces usually receive direct and equal amount of sunlight. Such leaves are called isobilateral leaves(monocotyledonous).

• e.g Zea maize (MAIZE)

ANATOMY OF ZEA MAYS (MAIZE)-MONOCOT

• EPIDERMIS• The epidermis is found on both upper and

lower surfaces of the leaf.• Epidermal layer are uniseriate.• Stomata are confined to both the epidermal

layers

• MESOPHYLL• It is not differentiated into palisad and spongy

tissue.• Thin walled, isodiametric chlorophyllous cells

having intercellular spaces amoung them.

• VASCULAR BUNDLES• Collateral and closed in shape• Smaller in size• Bundle sheath contain starch grain• xylem consist of vessels and phloem of sieve tube

and companion cells• Sclerencyma cells give mechanical support to the

leaf