Transport in Plants Flashcards
What is lignin?
A hard, strong, waterproof substance that forms xylem walls
What are some characteristics of xylem vessels?
Transport Water and Minerals from Roots up
One-way
Made of dead cells
Give structural support to plant
What are some characteristics of phloem tubes?
Transport sucrose and amino acids THROUGHOUT plant.
Two-way
Made of living cells
Partially Permeable to allow sugar
Why do xylem vessels have parts of them removed?
So that water can flow without being stopped
What is the arrangement of xylem and phloem vessels in a root?
Xylem makes a star shape inside a circle.
Phloem fills the gaps between the star and the circle
XPPPX
PPXXXPP
XXXXXXXX
PPXXXPP
XPPPX
What is the arrangement of xylem and phloem vessels in a stem?
xylem on the inside, phloem on the outside
What is the arrangement of xylem and phloem vessels in a leaf?
Xylem on top and phloem under
What is the function of root hairs and how are they adapted to fit it?
Root hairs perform water uptake by osmosis and have a large surface area, similar to villi.
Define transpiration
The loss of water vapour through leaves
State the process of transpiration in terms of leaf tissue
Water enters leaf by xylem
Water moves to mesophyll by osmosis
Water evaporates into air gaps
Water vapour diffuses out of the stomata
What is transpiration pull (higher, detailed)
A force that reduces pressure at the top of xylem vessels, leading to more water being pushed up there.
This happens to keep water flowing up to leaves.
How does temperature affect transpiration rate
The higher the temp. the faster the diffusion/osmosis, therefore faster transpiration
How does humidity affect transpiration rate
The more water present in the air, the less the net movement of water out of the stomata, therefore slower transpiration.
How does wind affect transpiration rate?
With wind present, the water diffusing out of the stomata will be blown away, and there is a higher diffusion gradient, therefore faster transpiration.
What is translocation?
The movement of sucrose and amino acids by phloem from sources to sinks.
