Download Exploring the movement of water and minerals in plants

Exploring the movement of water and
minerals in plants
Aseel Samaro
Introduction
 Water is needed in cells to support the plant and
to photosynthesise. Minerals in the soil dissolve
in water.
 How do plants get the water and minerals they
need? How do they move through the plant?
The saguaro cactus
Taking water in
 Plants take in water and dissolved minerals through their roots.
 The roots grow downwards and can also spread out underground to absorb
water and minerals from a large area.
 Roots anchor plants firmly in the ground.
 Water and minerals move from the roots, up the stem or tree trunk to the
leaves and flowers.
 Water in plant cells causes them to swell and become rigid.
Plants native to the
Sonoran Desert in the
Western USA.
Why do these plants
have differently
shaped root systems?
Name two functions of the roots.
Look at Figure 2.2.7b. Why do these plants have differently
shaped roots?
Why does water move to the leaves?
Name two functions of the roots.
Roots take up water and minerals; and anchor the plant
Look at Figure 2.2.7b. Why do these plants have differently
shaped roots?
to get water from different parts of the soil
Why does water move to the leaves?
for photosynthesis
Keeping the water
 Plants can lose water from the leaves through the stomata, which let in carbon dioxide.
Stomata close in hot conditions.
 The loss of water from a leaf is called transpiration.
 Plants lose most water when it is dry, hot and windy.
 Leaves have a waxy cuticle to prevent water loss
 The cuticles of desert plants are much thicker and waxier compared to other plants.
 Their leaves are often small or needle-like, which also prevents too much water loss.
 Some plants have curled or folded leaves.
 The curl reduces the surface area of the leaf. It also traps moist air to
help reduce transpiration further.
How is the saguaro cactus adapted to
prevent water loss?
Some plants have curled or folded leaves to
reduce water loss.
What is transpiration?
In what conditions will plants lose least water?
Describe how plants can reduce water loss.
Draw a diagram to show the movement of water through a plant.
What is transpiration?
Movement of water through a plant until it evaporates from the leaves
In what conditions will plants lose least water?
Cold; wet; no wind
Describe how plants can reduce water loss.
By closing the stomata; some have small or needle-like leaves
Draw a diagram to show the movement of water through a plant.
Arrows going from soil water into the roots; up the stem; into the leaves; then
showing water evaporating
Looking at cells
 Water and minerals move from the roots up the plant, in a series of cells in
the stem.
 These xylem cells form a pipeline through the plant.
 The roots of the plant have special cells called root hair cells.
 These have long, hair-like extensions that penetrate between the soil
particles.
 They have a large surface area through which they can absorb water.
 The guard cells are also important for controlling water loss.
 When the guard cells are swollen with water, they open the stomata
to let excess water leave the leaf.
 When the guard cells contain little water, they close the stomata.
How are these xylem cells
adapted to their function?
How effective are the adaptations of xylem, stomata and root cells for
transpiration?
How effective are the adaptations of xylem, stomata and root cells for
transpiration?
The root has not got a large enough area to take up enough water, so
the root hairs increase the surface area. They have no chloroplasts;
because they receive no light to photosynthesise. In the xylem, there
are no cell walls at the ends, so it makes a tube to allow quick
transport of water and minerals.
Did you know…?
 The tallest plants in the world are the giant redwood trees in
California.
 They can reach over 100 m in height. Water travels in the xylem
cells from their roots right up to the highest leaves.
Thank you