transpiration

Question 1

what is the palisade mesophyll?

Answer 1

where photosynthesis takes place

Question 2

what is the xylem tissues function

Answer 2

transports water and dissolved mineral ions from the roots of the leaves

Question 3

how does water enter roots?

Answer 3

through root hair cells

Question 4

what is transpiration

Answer 4

where water is constantly evaporating from the surfaces of leaves.

Question 5

explain the process of transpiration

Answer 5

• with the evaporation of water from cells inside the leaf
• water vapour then diffuses throughw the air spaces in the spongey mesophyll and out of the leaf through the stomata
• now water passes from the xylem into the leaf to replace the water thats been lost
• finally, water is drawn into the root hair cells and up the xylem vessels to the leaf.

this whole process is called the transpiration stream

Question 6

why does the water pass from the xylem into the leaf?

Answer 6

to replace the water loss

Question 7

what does transpiration do?

Answer 7

• brings water to the leaf. Water is required for photosynthesis
• Transpiration stream transports dissolved mineral ions such as magnesium which play important roles in the plant
• Evaporation of water from the leaf cools the leaf down especially in warm weather.
• the stomata now open to allow carbon dioxide to enter, once stomata open, water vapour can now pass out of the leaf

Question 8

explain the factors that affect rate of transpiration (limiting factors)

Answer 8

•the rate of transpiration is greater at higher temperatures
-this is because evaporation is faster at higher temperatures

•Dry conditions, when air is not humid
-evaporation also takes places more quickly under dry conditions

•rate of transpiration increases during windy conditions
-wind removes any water vapour allowing more water to evaporate

•rate of transpiration increases when light intensity increases
-high light intensity increases the rate of photosynthesis

Question 9

HOW STOMATA WORKS
what are stomata surrounded by?
what does this do?

Answer 9

-2 guard cells
-when light intensity is high during the day, the guard cells swell and change their shape
causing stomata to OPEN
() —> (())

Question 10

what happens when stomata opens

Answer 10

carbon dioxide can diffuse into the leaf and be used in photosynthesis

Question 11

when do stomata plants close?
how do they do this?
what does this then mean

Answer 11

under hot conditions to reduce water loss by TRANSPIRATION

now the plant cannot photosynthesise

Question 12

when do stomata plants open?

Answer 12

at high light intensity eg during the day