Leaves
Stone Bridge High School
Environmental Class
Mr. Luis A. Velázquez
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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?
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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
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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
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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)
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Stomata (H)
Guard cells (I) - specialized cells surround the stomata and
are shaped like two cupped hands.
Leaf Information
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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
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Different type of leaf arrangement :
– Alternate
– Opposite
Leaf Anatomy
Review
Worksheet
Leaf Quiz
The End
Simple Leaf
Compound leaf
Leaf Arrangement
Simple Leaves - Margin Structure
Types of Compound Leaves
Leaf Parts