Lecture 2 - Water Potential Flashcards
what direction does water move through the xylem
roots to shoots
steps of water movement in plants (4 steps)
- Water moves from soil to the root
- Water gets through the root
- Water moves up through the xylem
- Water moves from leaf to air
What did Malpighi and Grew find out by observing plant conducting tissues
They found out that plant structures that look similar to animal vasculature might be conducting tissues
What did Stephen Hales find out
that plant roots do not push up water, but pull water up by transpiration from the leaves
Important properties of water
1) Water is cohesive
2) Water is an excellent solvent
3) Water can dissociate into ions
4) Water has a high latent heat of vaporization (high boiling point)
5) Water has a high tensile strength
cohesive
Molecules stick to each other
How is water cohesive
Water is a polar molecule and is electronegative which forms hydrogen bonds with other water molecules
why is it important that water has a high latent heat of vaporization
It makes it more stable and in turn provides thermal stability to biological organisms
how many kJ is needed to cause 1 mole water to go from liquid - vapor state
44kJ
tensile strength
ability to resist a pulling force of molecules before breaking their bonds
Adhesion
a molecule is attracted to the other type of molecule
Surface tension
the property of liquid surfaces which allows it to resist an external force, due to the cohesive nature of its molecules
how do plants bring water from the roots to shoots
capillary action (capillarity)
what is the greek symbol for water potential
psi (baby trident shaped symbol)
water potential
ability of water molecule to move freely in solution/its potential energy
