LeavesStone Bridge High School

Environmental ClassMr. Luis A. Velázquez

The leaf is a part of the plant that is charge of making food for the plant.

99% of the photosynthesis is done here.

Is known as the photosynthetic organ.

What are leaves?

The leaf is the primary photosynthetic organ of the plant. It consists of a flattened portion, called the blade, that is attached to the plant by a structure called the petiole.

Sometimes leaves are divided into two or more sections called leaflets.– Leaves with a single undivided blade are called

simple, those with two or more leaflets are called compound.

Parts of the leaves Petiole - a thin stalk that connects the blad of the

leaf to the plant's stem. Blade - a thin, flat part of the leaf that extends off

the end of the petiole. It is green as it contains cholorophyll which is necessary in making the plant's food..– The blade contains veins which help bring in the water

necessary for photosynthesis and to transport food out to all parts of the plant. The xylem is responsible for water transportation and the phloem for food.

Leaves Parts Cuticle (A), The outer surface of the leaf has a thin waxy

covering called the this layer's primary function is to prevent water loss within the leaf.

Epidermis (B) The epidermis also lines the lower area of the leaf.

The vascular tissue : ( C, D & E ) Xylem and Phloem. xylem and phloem are found within the veins of the leaf.

Mesophyll. The word mesophyll is greek and means "middle" (meso) "leaf" (phyllon). Mesophyll is where photosynethesis actually occurs Mesophyll can then be divided into two layers, the

– palisade layer (F)– The spongy layer (G)

Stomata (H) Guard cells (I) - specialized cells surround the stomata and

are shaped like two cupped hands.

Leaf Information Leaves can be of many different shapes:

Primarily, leaves are divided into simple - a single leaf blade with a bud at the base of the leafstem; or compound - a leaf with more than one blade. 

All blades are attached to a single leafstem.  Where the leafstem attaches to the twig there is a bud.

There different types of compound leaves:– Pinnate– Palmate– Doubly

Different type of leaf arrangement :– Alternate– Opposite

                                                                  

Leaf Anatomy

Leaf Quiz

Review Worksheet

The End

Simple Leaf

Compound leaf

Leaf Arrangement

Simple Leaves - Margin Structure

Types of Compound Leaves

Leaf Parts