Photosynthesis
All living things need food for energy but, unlike animals,
plants make their own food. The plant’s leaves absorb sunlight
and a gas called carbon dioxide from the air, while the roots
take up water. Inside the leaf, energy from the sunlight is
used to turn the carbon dioxide and water into sugary food
for the plant. The process is called photosynthesis, which
means “making things with light.” The plant also creates
oxygen as a by-product of photosynthesis, which it releases
through its leaves.
Tree roots can take up as much space
underground as branches do above it.
They give the tree stability and take
up water and minerals.PLANT LIFELIVING WORLDTAKE A LOOK: TRANSPIRATION OPEN STOMA Each stoma or pore is
flanked by a pair of guard cells, which open
and close to control the amount of gas and
water vapor passing in and out of the leaf.Guard cell StomaThe surface of a leaf is covered in
microscopic pores called stomata. When
a stoma opens it allows carbon dioxide
into the leaf for photosynthesis, and also
water vapor to escape in a process called
transpiration. The lost moisture is
replaced by water drawn up through the
roots. Water from the soil contains many
of the minerals that the plant needs.Leaf colors
Leaves contain a variety of pigments.
In spring and summer the green pigment
chlorophyll masks the colors of the
others. In winter, lack of sunlight forces
deciduous trees to stop photosynthesis.
The chlorophyll in their leaves is broken
down, allowing other colors—yellow, red,
and brown—to show.The plant’s leaves absorb
carbon dioxide from
the air and use it in
photosynthesis. INSIDE A LEAF
Photosynthesis takes place
within tiny structures called
chloroplasts, inside leaf cells.
Chloroplasts are green
because they contain a
pigment called chlorophyll.At night the plant takes some of
the oxygen back in to help it
burn its own sugars for energy.Plants need water to stay
strong and healthy. Water
is carried around a tree in
minute tubes called xylem.CARBON DIOXIDEOXYGENWATER87