Download Water_Potential__Transpiration

Water Potential & Transpiration
AP Lab #9
Plant Structure – Ch 35
Transport in Plants – Ch 36
Water potential
• Water potential = potential energy of water
– Amount of water and its potential “pull”
– ml of water/mass of plant
• Recall water’s essential properties that lead
to its universality in living organisms…
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Water loss from a plant – transpiration
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Basic plant structure
• Roots
• Stems
• leaves
3 main cell types make up tissue types
– parenchyma
– collenchyma
– sclerenchyma
3 main tissue types
• Dermal tissue
• Ground
tissue
• Vascular
tissue
Transport through the plant - Vascular Tissue
– Water & solute transport vs. sugar transport
• Xylem
• phloem
Transpiration - from root to stem to
leaf
•
1. Water enters root –
low water potential and
hydrostatic pressure
2. Water enters stem –
capillary action and adhesion;
water potential
3. Water leaves leaf –
evaporative pull and water
potential
A closer look at the root
Water moves into root via apoplastic
movement and symplastic movement
Ions taken into root from the soil water
create a low water potential in root
hairs
Water moves around and through Parenchyma
cells that make up the ground tissue of the root,
into the vascular cylinder
•
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Movement through stem is via vascular bundles
leaves
• Water potential of
outside environment
is less than internal
environment
• Stomata regulate the
flow
• Water moves from
high water potential
to low
• Flow of water?
Your turn…
• Hypothesize on how the environmental
conditions of our lab will affect water
movement
• Trace a water molecule from root to leaf, using
all appropriate vocabulary and plant
structures.
– Water vocab
– Plant structure vocab
Environmental challenges for plants
•
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