Transcript Why Do Leaves Change Colors?

What are leaves and
what do they do?
Photosynthesis
•The process in which
plants turn water and
carbon dioxide into
sugar is called
photosynthesis.
•Plants use sunlight to
turn water and carbon
dioxide into glucose
(sugar).
Photosynthesis (continued)
•Cells in the plants leaves, called chloroplasts, contain a green
pigment called chlorophyll which interacts with sunlight to split the
water in the plant into its basic components.
•Carbon dioxide then enters the leaf and combines with the stored
energy in the chloroplasts through a chemical reaction to produce a
simple sugar.
•The sugar is then transported from the leaf to the rest of the plant
or tree to be used for energy.
•Oxygen is released from the leaf through the process of
Photosynthesis.
Why are leaves green?
•There are different color pigments in leaves. They are
Chlorophyll, Xanthophyl, Carotene, and Anthocyanins.
•Chlorophyll is the most abundant pigment in a leaf and
gives it a green color. The other pigments cannot be
seen.
Autumn Leaves
•In Autumn, the days grow shorter and
the temperature drops.
•Leaves respond to the decreasing
amount of sunlight by producing less
and less chlorophyll.
•When chlorophyll production stops,
the other pigments in the leaves begin
to show through.
Factors that influence the amount of fall color the
leaves will wear each year include:
•Rain
•Amount of sugar in the leaves
•Wind
•Temperatures
Cool, bright sunny days and chilly nights create the
brightest colors. The colors also depend on the makeup
of the trees and other plants.
Leaf Colors
•YELLOW- This is caused by the pigment Xanthophyl.
Some trees that turn this leaf color are: Ash, Birch, Beech, Butternut,
Elm, Hickory,Poplar, and Black Maple.
•RED- This is caused by the pigment Anthocyanin.
Some trees that turn this leaf color are: Northern Red Oak, Red
Maple, and Sumac.
•ORANGE- This is caused by the pigment Carotene.
Some trees that turn this leaf color are: Sugar Maple and some
Oaks.
Winter is Coming!
Leaves can freeze in the winter. They
must be shed so that the rest of the plant
can survive throughout the winter.
•A layer of cells, called the separation
layer, forms at the base of the leaf stem.
•When this layer is complete, the leaf is separated from the tissue
that connected it to the branch, and it falls.
Oak leaves are an exception. They never fully detach and remain
on the tree throughout the winter.
Evergreen trees do not lose their leaves because their leaves contain
substances that resist freezing.
Leaves Lesson-Fifth Grade
Created by
Janice Sullivan
EDU 6621
Integrating Technology
Into The Curriculum
Professor Morote
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