Transport systems plants Flashcards
What are the plant organs?
Roots Stems Leaves
A leaf structure diagram contains…
Upper Epidermis Palisade Mesophyll Spongy Mesophyll Vein (consisting of xylem and phloem) Lower Epidermis Guard Cells Stomata
What are the Xylem vessels and what is their function?
They are dead cells, and are used to transport water and dissolved solutes
What is Phloem and what is it’s function?
It’s made of living cells, and it transports sugars
How do water and minerals move through the plant?
Water and minerals enter the plant through the root hairs and are transported in dead Xylem vessels (via osmosis) , to the stem and leaves for transpiration
Structure of the Xylem vessels
Thick, cellulose cell walls strengthened by lignin rings
(to withstand the pressure changes as water moves through the plant)
How does water travel to the Xylem vessels?
Via Root Cells which are covered in hairs to increase the surface area and therefore increase the speed at which water can be transported into the roots
Structure of the Phloem Tissue
- Living cells(called seive cells) with end walls that have pores.
- Companion cells provide the energy for the sieve cells.
The process of Transpiration
The loss of water from leaves by evaporation through the stomata.
What effects the rate of Transpiration?
Wind Speed - Increase the rate
Humidity - Decrease the rate
Higher Temperature - Increases the rate
Big Surface Area - Increases the rate
Features of leaves?
Large surface area
Thin
Thin waxy cuticle
Thin transparent epidermis.
Function of large surface feature in leaves.
Maximise light absorption
Function of a thin leaf
Short distance for carbon dioxide to diffuse into leaf cells
Function of thin waxy cuticles
Protects the leaves without blocking out light
Function of Thin transparent epidermis
Allows light to reach the palisade mesophyll cells
What apparatus is used to investigate the rate of transpiration.
Potometer
The transpiration steam is important because:
-It carries water for photosynthesis to the mesophyll cells: the upper layer of cells where photosynthesis mostly takes place in the leaves.
The water carries essential mineral salts dissolved in solution
Water taken up by the roots of a plant is transported through a plant to the leaves where some of it passes into the air. The stages of the process are:
Soil to xylem Xylem to leaf to air
Stages of soil to xylem
- Water enters root hair cells 2. Water moves from cell to cell through the root cortex by osmosis down a concentration gradient 3. centre of the root the water enters the xylem vessels (vein-like tissues that transport water and minerals up a plant)
Xylem to plant to air
- Water moves from the xylem vessels into the mesophyll cells where it can be used for photosynthesis.
- Some of the water evaporates into the surrounding air spaces inside the leaf and then diffuses out through the stomata into the surrounding air.
Name the diagram
The structure of a leaf has adaptations so that it can carry out photosynthesis effectively.
A leaf needs:
a way to transport water to the leaf, and glucose to other parts of the plant(xylem and phloem)
a way to exchange carbon dioxide and oxygen(stomata)
the ability to absorb light energy efficiently(palisade mesophyll)
What are the pores for in the end walls in phloem
To transport sugar from cell to cell.
