Plant Nutrition and Transport Flashcards
How do plants produce their own ‘food’ ?
Photosynthesis
Where does photosynthesis occur?
In the leaves of all green plants
In chloroplasts
What is the equation for photosynthesis?
carbon dioxide + water = glucose + oxygen
6CO2 + 6H2O = C6H12O6 + 6O2
What does photosynthesis convert?
light energy into chemical energy
When is the chemical energy released from photosynthesis?
during respration
How are plant leaves adapted for photosynthesis?
They are thin and flat
So that as much light can be absorbed as possible and the distance that gases need to diffuse are very short
What is the top layer of a leaf called?
The waxy cuticle
How does the waxy cuticle help reduce water loss?
by evaporation
What layer is after the waxy cuticle in a leaf?
The upper epidermis
Why is the upper epidermis transparent?
So that light can pass through it to the palisade layer
Where are most choloroplasts found in, in a leaf?
The palisade layer, near the top where they can get the most light
What bundles do leaves have a network of?
vascular bundles
What are the two transport vessels in the vascular bundles?
Xylem and Phloem
What are stomata?
little holes in the leaf, which let CO2 diffuse directly into the leaf
What are the three limiting factors of photosynthesis?
Light
Carbon Dioxide concentration
Temperature
In photosynthesis, if the light intensity increases…
The rate of photosynthesis will increase steadily, but only up to a certain point
How can you test a leaf for starch?
Kill plant first by dining in boiling water
(stops any chemical reactions)
Put the leaf in boiling tube with some ethanol and heat in water bath
(gets rid of any chlorophyll)
Rinse off the leaf in cold water and add a few drops of iodine solution.. if starch is present.. leaf will turn gluey-black
Only the green parts of the plant contain
chlorophyll
How can you show CO2 is needed for photosynthesis?
With a sealed bell jar, soda lime, and a light
The soda lime absorbs CO2 out of jar
Then test leaf for starch
How can you show light is needed for photosynthesis?
Place a plant in a cupboard
Test for starch
What can be used to measure the effect of light intensity on the rate of photosynthesis?
Canadian Pondweed
White light at specific distances
syringe at other end
The faster the rate of oxygen production…
The faster the rate of photosynthesis
What are the three minerals ions a plant needs for growth?
Nitrates
Phosphates
Potassium
(small amounts of magnesium)
Where do plants get their mineral ions?
In the soil
What do Nitrates contain and needed for?
contain nitrogen for making amino acids and proteins
needed for cell growth
What happens to a plant if it does not receive enough Nitrates?
It will be stunted and have yellow older leaves
What do Phosphates contain and needed for?
Contain phosphorus for making DNA and cell membranes
needed for respiration and growth
What happens to a plant if it does not receive enough Phosphates?
It will have poor root growth and purple, older peaves
What is Potassium needed for?
To help the enzymes needed for photosynthesis and respiration.
What happens to a plant if it does not receive enough Potassium?
The plant will have poor flower and fruit growth and discoloured leaves
Why is magnesium needed in a plant?
It’s required for making chlorophyll and without the leaves will have yellow leaves.
What are plants two main transport systems?
Xylem and Phloem
What do Xylem tubes transport?
water and mineral salts from roots to shoot
What do Phliem tubes transport?
food
What are the cells on plant roots called?
Root hair cells
How is water taken in through root hair cells?
via osmosis
What is the phloem’s tissue made of?
living cells
How do root hair cells help the uptake of water?
They greatly increase the surface area of the root
How are minerals taken in through root hair cells?
via active transprt
What is transpiration?
The water loss in a plant
What is transpiration caused by?
evaporation and diffusion of water from a plants surface
Where does most transpiration happen?
In the leaves
How are leaves adapted for transpiration?
like photosynthesis:
Stomata helps the leaves exchange gases easily
How does water escape the plant?
because theres more water inside than outside, the water escapes from the leaves through the stomata by diffusion
The continuos flow of water in a plant is known as…
the transpiration stream
What is the rate of transpiration controlled by?
The stomata
Where are most stomata found?
on the underside of the leaf (reduce water loss)
What are the four main things that affect the transpiration rate in plants?
Light Intensity
Temperature
Wind Speed
Humidity
In terms of transpiration.. the brighter the light…
the greater the transpiration rate
How does light affect transpiration rate?
Stomata close as it gets darker
Photosynthesis can’t happen in the dark, so they don’t need to let CO2 in, therefore are closed
When stomata are closed, little water can escape
How does temperature affect transpiration rate?
The warmer it is.. the faster the transpiration rate
When it’s warm, water particles have more energy to evaporate and diffuse out of the stomata
How does wind speed affect transpiration rate?
If low, water vapour surround the leaf and doesn’t go away.
This means theres a high concentration of water particles outside the leaf so diffusion doesn’t happen as quickly.
If windy, water vapour is swept away, maintaining a low concentration of water in the air outside the leaf - diffusion happens quickly
How does humidity affect transpiration rate?
the drier the area outside the leaf, the faster transpiration happens
(diffusion thing)
What piece of equipment is used to estimate transpiration rate?
A potometer
What does a photometer measure
water uptake by a plant
what is the function of phloem vessels in plants?
transport sugars like sucrose, and amino acids from where they’re made in the leaves tto other parts of the plant
what is the movement of food substances around the plant by the phloem known as?
translocation
