Water movement in plants

Question 1

what wp does pure water have

Answer 1

0

Question 1

water potential is?

Answer 1

measure of tendancy water mols to diffuse area to another

Question 2

how does water enter (wp)

Answer 2

wp outside cell higher so water enters by osmosis

Question 3

what happens when water enters cell

Answer 3

turgid
contents press against wall for pressure potential

Question 4

how does water leave cell (Wp)

Answer 4

wp inside is higher so water leaves by osmosis

Question 5

what happens when water leaves cell

Answer 5

less tugid
cytoplasm and vacuole shrink
cell membrane pulls from wall (plasmolysis)

Question 6

what happens when no pressure potential

Answer 6

incipient plasmolysis

Question 7

Water movement at roots?

Answer 7

mineral ions move in down conc gradient into root hair
or active transported in
lowers wp in root so more enters via osmosis

Question 8

how does water move cell to cell

Answer 8

water with ions moves through cortex till reach xylem
transporter proteins pump nitrates into xylem lowering its wp so water moves in by osmosis

Question 9

general path from root hair to xylem

Answer 9

root hair
epidermis
cortex
endodermis
pericycle
xylem

Question 10

What is the apoplast pathway

Answer 10

water moves between cellulose strands in cell wall and spaces between cells
no membranes so ions stay with water so NON SELECTIVE

Question 11

What is sYmplast pathway

Answer 11

enters cYtoplasm thru cell membrane of root hair then cell to cell through plasmodesmata

Question 12

what is vacuolar pathway

Answer 12

similar to symplast but can enter vacuoles aswell

Question 13

what ways does water move up stem

Answer 13

root pressure
capillary action
transpiration pull

Question 13

what is the casparian strip

Answer 13

endodermis layer surrounding xylem in root
has waterproof suberin in wall called

Question 14

what does the casparian strip do

Answer 14

ensures control of what enters xylem

Question 15

what is root pressure

Answer 15

active transport minerals from endodermis to xylem
so water enters root and pushes water up xylem up to few metres

Question 16

what is capillary action

Answer 16

water polar so attracted sides xylem by ADHESION
vessels narrow so adhesion can pull water up

Question 17

what is transpiration pull

Answer 17

water attracted to water by COHESION
continuous column
water lost top by evaporation and then whole column pulled up (transpiration stream)
type of mass flow
causes tension in water and lignin stops vessel collapse

Question 18

what is cohesion-tension theory

Answer 18

unbroken column water
water leaves through stomata so water potential lowered in cells surrounding so water enters by osmosis
continues until water leaves xylem to leafs