plant stems and xylem

Question 1

structure of xylem

Answer 1

cellulose cell wall
lignin
made of hollow dead cells
no end walls
pits in walls
open ends

Question 2

function of xylem

Answer 2

transport water and mineral iosions from root to leaves
structural support

Question 3

phlome structure

Answer 3

cellulose cell wall
sieve tube
sieve plates with sieve pores
companion cell linked by plasmodesmata
living tissue

Question 4

function of phlome

Answer 4

transport of solutes from source to sink in translocation.

Question 5

structure of schlernechyma fibres

Answer 5

cellulose cell walls that are thickly lignified
dead hollow tubes
pits
long narrow and pointed at ends

Question 6

function of schlerenchyma fibres

Answer 6

structural support

Question 7

lignin in xylem=

Answer 7

waterproof

Question 8

lignin= cellulose microfibrils in xylem

Answer 8

strength- prevent collapse

Question 9

large cross sectional area- xylem

Answer 9

larger volume of water transported

Question 10

pits in walls

Answer 10

sideways movement of water between xylem vessels

Question 11

no end walls -xylem

Answer 11

continuous dead hollow tube, reduce resistance to water flow

Question 12

lignin in rings-xylem

Answer 12

stretch and flexibility as plant grows

Question 13

transpiration

Answer 13

loss of water vapour from surface of plants

Question 14

transport from root to leaves

Answer 14

water evaporates from leaf cell through transpiration
creating low hydrostatic pressure in leaves- draw out water from xylem vessels (osmosis)
transpiration stream pulled up xylem by capillary action due to cohesion and adhesion
water moves into roots by osmosis- high hydrostatic pressure
water move along pressure gradient - high roots to low leaves- mass flow