Transcript B5: Transportation - HIS-IGSci-Bio

B5:
Transportation
Transport in Plants
State the functions of xylem
and phloem
 Flowering
plants have two separate transport
systems: xylem and phloem.
 These tissues are found throughout the plant
body in roots, stems and leaves,
 Xylem vessels transport water and mineral ions
from the roots up the stem to the leaves.



Roots absorb water and mineral ions from the soil.
These travel in the xylem upwards in the stem to
the leaves, flowers and fruits.
This is one-directional movement: from roots, via
Water transport
the stem, to the leaves.
Water movement in plants
State the functions of xylem
and phloem
 Phloem
vessels transport sucrose, amino acids and
hormones to other parts of the plant.



Sucrose is a soluble complex sugar
Sucrose is made from the sugars made in
photosynthesis and from the starch stored in roots and
stems.
Substances are moved in two directions in the phloem:
 downwards
from leaves to roots
 upwards from leaves to flowers, fruits and buds
 Upwards from storage organs to new stems and leaves.
Phloem loading video
Plant tissue
animation
Water
movement
animation
Inside a root
Inside a stem
Sink and source
Up the stem
Identify root hair cells and
state their functions
 Roots


Anchor the plant in the soil
Take up water and mineral salts
 Root



have 2 functions:
hairs are microscopic
Water passes into the root hair from the soil via
osmosis.
This process continues through all the cells until the
water reaches the xylem.
The xylem transports the water up the stem.
 Structure

of root hairs:
Long and thin with a large surface area.
Absorption by roots
Transpiration
 The
evaporation of
water from the leaves
and the loss of water
vapour to the
atmosphere.

Water only diffuses out of
the leaf when the
stomata are open.
 The
flow of water up the
stem relies on:


Cohesion of water
molecules to each other
Adhesion of water
molecules to the xylem
Factors affecting
transpiration
 Use
your textbook p93 to summarise the factors
that will affect the rate of transpiration in a plant
(draw graphs if appropriate)




Light
Humidity
Temperature
Wind
Page 98 – 99 complete the
exam-style questions: 1 - 7