Download Transport in Plants

Transport in Plants
Title: Transport in Plants
Lesson objective:
1.Can I explain the role of vascular tissue?
Grade C/B
2.Can I describe the distribution of vascular
tissue in plants? Grade D/C
Starter: Name specialized cells in the
plant and what their roles are….
Root hair cell
Epidermal layer
with root hair
cells – increase
surface the area.
Absorb minerals by
active transport
and water by
osmosis from the
soil.
Vascular tissue in Roots…
Vascular tissue in Stems…
Sclerenchyma
tissue
Phloem
Cambium
Xylem
Vascular tissue in Leaves
Xylem…
Tissue – tubes with no
end walls, fibres and
parenchyma cells.
Xylem vessels – long
dead cells (empty) with
thick walls (lignin) and
pits.
How is xylem
adapted to its
function?
Lignin – waterproofs
cells, strengthens the
vessels, forms patterns
(allows flexibility).
Phloem
Tissue – sieve tube
elements and
companion cells
Sieve tubes – little
cytoplasm and no nucleus,
lined up, cross walls that
are perforated (sieve
plates).
Companion cells – large
nucleus and dense
cytoplasm, mitochondria
(metabolic processes),
plasmodesmata (links).
To do…
Microscope work – make schematic
diagrams of the root and stem, fully
labelled.
Title: Transpiration
Lesson objective:
1.Can I describe how transpiration occurs
and how to measure it? Grade C
2.Can I explain transpiration and what
could affect the rate ? Grade B/A
Homework: Notes on xylem and phloem….
Starter: Identify the plant organ and
add the labels in….
Specialised tissues…
In your groups – make a mini-factfile on one
of the three tissues: xylem, phloem or
stomata…
You can:
• Use your mobile phones – video your fact
file
• Use the paper provided to make a
‘leaflet’ 
You have 10 minutes…..
Stomata
Pathway of water:
Xylem bring water to leaf,
Exam question
Passes to mesophyll cells by osmosis,
Water evaporates from surface of mesophyll cells to the air
spaces as water vapour,
Water vapour collects (higher potential) and so diffuses out of
the leaf.
Transpiration…
Transpiration is the
loss of water
vapour from the
leaves.
Involves 3 processes:
• Osmosis from xylem
to mesophyll cells
• Evaporation
• Diffusion of water
out the stomata
The
potometer
Title: Transpiration
Lesson objective:
1.Can I describe the factors that affect the
rate of transpiration? Grade C
2.Can I explain how plants reduce water
loss? Grade B/A
Starter: Exam question….
Transpiration stream…
Useful to plant:
• Water is needed in leaves for
photosynthesis
• Water is needed for cells to grow and
elongate
• Keeps cells turgid
• Flow of water carries useful minerals
• Evaporation keeps plant cool
Factors affecting transpiration..
Number of leaves
Number, size and position of stomata
Cuticle
Light
Temperature
Humidity
Air movement
Water availability
Reducing water loss…
Exam question
Unavoidable….
Plants exchange gases via stomata during
the day.
How to reduce loss?
Waxy cuticle
Stomata found on undersurface of leaf
Stomata close at night
Loss of leaves
Loss of too much water…?
Xerophytes…
Plants that are adapted to living in dry/arid
conditions – they are able to reduce
water loss from leaves in numerous
ways….
Rolled leaf –
lower epidermis
is not exposed.
Thick waxy
cuticle
Trapped air in
centre with high
water potential
Hairs reduce
movement of air
Stomata in pits
to trap air with
moisture