3.1.3 e adaptations of plants

Question 1

what are mesophytes?

Answer 1

plants that are adapted to a habitat with adequate water

Question 2

what are xerophytes?

Answer 2

plants that are adapted to a dry habitat

Question 3

what are halophytes?

Answer 3

plants that are adapted to salty habitat

Question 4

what are hydrophytes?

Answer 4

plants that are adapted to a freshwater habitat

Question 5

what are the adaptations of xerophytes?

Answer 5

• thick cuticle
• small leaf surface area
• low stomata density
• suken stomata
• stomatal hairs (trichomes)
• rolled leaves
• extensive roots

Question 6

what does a thick cuticle do?

Answer 6

stops uncontrolled evaporation through leaf cells

Question 7

what does a small leaf surface area do?

Answer 7

less surface area for evaporation

Question 8

what does a low stomata density do?

Answer 8

smaller surface area for diffusion

Question 9

what do sunken stomata do?

Answer 9

traps humid air around it

Question 10

what do trichomes do?

Answer 10

traps humid air around the stomata

Question 11

what do rolled leaves do?

Answer 11

confines all the stomata in a microclimate of humid air

Question 12

what do extensive roots do?

Answer 12

can access water way below the surface
shallow roots can absorb any available water before a rain shower

Question 13

what is the root system of marram grass?

Answer 13

long vertical roots that penetrate deep into sand.
have a mat of horizontal rhizomes that have many more roots develop to form extensive network that helps to change their environment and enable sand to hold more water

Question 14

why do surface water plants need to float?

Answer 14

to get light needed for photosynthesis

Question 15

what is a major problem for hydrophytes?

Answer 15

water logging- air spaces need to be full of air not water for plant to survive

Question 16

what are the adaptations of hydrophytes?

Answer 16

very thin or no waxy cuticle
many open stomata on the surface of the leaves
reduced structure of the plant
wide, flat leaves
small roots
large surface area of roots and stems underwater
air sacs
aerenchyma

Question 17

why do hydrophytes have a very thin or no waxy cuticle?

Answer 17

do not need to conserve water as there is lots of water available

Question 18

why do hydrophytes have many open stomata on the surface of the leaves?

Answer 18

maximising gas exchange

Question 19

why do hydrophytes have a reduced structure of a plant?

Answer 19

water supports leaves and flowers

Question 20

why do hydrophytes have wide, flat leaves?

Answer 20

spread across surface to capture as much light as possible

Question 21

why do hydrophytes have small roots?

Answer 21

less need for uptake of water because water can move into stems and leaf tissue directly

Question 22

why do hydrophytes have large surface area of roots and leaves that are underwater?

Answer 22

maximises area for photosynthesis
allows oxygen to diffuse into submerged plants

Question 23

why do hydrophytes have air sacs?

Answer 23

to enable leaves to float on water

Question 24

what are aerenchyma?

Answer 24

specialised parenchyma tissue that forms in the leaves, stems and roots
has many large air spaces that seemed to be formed by apoptosis in normal parenchyma cells

Question 25

function of aerenchyma

Answer 25

making leaves and stems more buoyant
forming a low resistance internal pathway for the movement of oxygen to tissues below water