Topic 3: Transport in plants p2

Question 1

Ways for xerophytes to conserve water

Answer 1

Ways for xerophytes to conserve water:
-A thick waxy cuticle
-Sunken stomata at pits
-Reduced number of stomata
-Reduced leaves
-Hairy leaves
-Curled leaves
-Succulents
-Leaf loss
-Root adaptation
-Avoiding the problems

Question 2

Thick waxy cuticle as an adaptation for conserving water

Answer 2

Thick waxy cuticle - minimises water loss - common in evergreen plants to surviving hot dry summers and cold winters where water is hard to obtain

Question 3

Sunken stomata as an adaptation to conserve water

Answer 3

Sunken stomata - stomata located in pits - reduced air movement - producing a microclimate of still humid moist air that reduces water vapour potential gradient - reduces transpiration

Question 4

Reduced number of stomata as an adaptation to conserve water

Answer 4

Reduced numbers of stomata - reduces the water loss by transpiration but also reduces their gas exchange capabilities

Question 5

Reduced leaves as a way of conserving water

Answer 5

Reduces leaves - reducing leaf area - reduces water loss - eg leaves of conifers reduced to thin needles - reduced sa:v ratio

Question 6

Hairy leaves as a way to conserve water

Answer 6

Hairy leaves - creates a microclimate of still, humid air reducing the water vapour potential and minimising the loss of water by transpiration from the surface of the leaf

Question 7

Curled leaves as a way to conserve water

Answer 7

Curled leaves - confines all the stomata within a microenvironment of still, humid air to reduce diffusion of water vapour from the stomata eg marram grass has this adaptation

Question 8

Succulents as a way to conserve water

Answer 8

Succulent - succulent plants store water in a specialised parenchyma tissue in their stems and roots - water is stored when it is in plentiful supply nd then used in times of drought

Question 9

Leaf loss as a way to conserve water

Answer 9

Leaf loss - some plants lose their lives when water is not available

Question 10

Root adaptations a way to conserve water

Answer 10

-Long tap roots grow deep into the ground and penetrate deep into the ground to acess water far from the surface
-Mass of widespread, shallow roots with a large surface area able to absorb any available water before a rain shower evaporates

Question 11

Avoiding water loss problems as xerophytes

Answer 11

Some xerophytes avoid water loss problems by losing their leaves and becoming dormant, or dying completely and leaving seeds behind to germinate and grow rapidly
-Others may survive as storage organs such as bulbs (onions, daffodils) etc

Question 12

Hydrophytes

Answer 12

Hydrophytes = plants that live in water and has special adaptations to cope with growing in water or being in permanetly saturated soil eg water lillies, water cress etc

Question 13

Why is it important for surface water plants that the leaves float?

Answer 13

It is important for surface water plants that the leaves float so they are near the surface of the water to get light needed for photosynthesis

Question 14

Adaptations of hydrophytes

Answer 14

Adaptations of hydrophytes:
-Very thin or no waxy cuticle as there is always water availble
-Many always-open stomata on the upper surfaces
-Reduced structure to the plant
-Wide flat leaves
-Small roots
-Large surface area of stems and roots under water
-Air sacs
-Aerenchyma (specialised parenchyma packing tissue)

Question 15

What is the turgor pressure in plant cells?

Answer 15

Turgor is pressure exerted by fluid in a cell that presses the cell membrane against the cell wall. Turgor is what makes living plant tissue rigid. Loss of turgor, resulting from the loss of water from plant cells, causes flowers and leaves to wilt.