water

Question 1

dicot root system

Answer 1

simple root system with a primary tap root

Question 2

monocot root system

Answer 2

complicated root system due to harsher environments with a primary seminal root (have crown roots + brace roots)

Question 3

ectomycorrhizal

Answer 3

• symbiotic relationship between fungi and plant roots
• components → mantle, cortex, harting net

Question 4

root tissue components

Answer 4

phloem, xylem (dead cells forming continuous tubes to the top of the plant) enveloped by endodermis, cortex

Question 5

apoplastic

Answer 5

route of water + solutes to travel via channels of cell wall → can freely move + diffuse

Question 6

symplastic

Answer 6

route of water + solutes to move into cell walls / membranes and travels via channels connecting cells

Question 7

casparian strip

Answer 7

seals endodermal walls + forces water into cells → stops water traveling via apoplastic route

Question 8

dicot stem xylem cells

Answer 8

organised in vascular bundles in a circular arrangement around the pith

Question 9

dicot stem secondary xylem cells

Answer 9

secondary xylem cells are produced, creating annual rings to increase the stem’s diameter and transport capacity

Question 10

xylem cells

Answer 10

dead at maturity (programmed cell death) and lose cytoplasm + connecting cell walls, so long tubes are formed

Question 11

xylem cell transport

Answer 11

suction due to external pressure of atmosphere → anti-gravitational transport of H2O

Question 12

cohesion-tension model

Answer 12

→ transport of H2O by capillary action (by xylem) through tension / negative pressure
- action 1 → attraction of like molecules (cohesion); H2O is cohesive because it is polar
- action 2 → attraction of unlike molecules (adhesion); between H2O + vessel walls

Question 13

transpirational pull

Answer 13

evaporation of water via the stomata from mesophyll cells in leaves creates negative pressure in the xylem that pulls H2O from roots + soil

Question 14

ABA

Answer 14

abscisic acid (plant hormone) → modifying ABA response pathways can make plants more amenable to drought

Question 15

adaptations to conserve water

Answer 15

• waterproof leaf surface
• succulent leaves + stems
• minimise leaf surface
• rolled leaves

Question 16

waterproof leaf surface as an adaptation to conserve water

Answer 16

hydrophobic cuticle made from cutin (aliphatic biopolymer) → epidermal layer is exposed to sun + evaporation of water from leaves without the cuticle

Question 17

succulent leaves as an adaptation to conserve water

Answer 17

waxy leaves with water storage inside through mucilaginous tissues that retain water through gel-like properties

Question 18

succulent stems as an adaptation to conserve water

Answer 18

no leaves + a waxy cuticle over the stem → reduced surface area for less transpiration; sunken stomata with nocturnal opening

Question 19

minimised leaf surface as an adaptation to conserve water

Answer 19

waxy cuticle coating on needle surfaces → barrier against evaporation + reflects sunlight; less surface area + sunken stomata → less transpiration

Question 20

rolled leaves as an adaptation to conserve water

Answer 20

reduces surface area exposed to sunlight + wind; creates microclimate within the rolled structure → less transpiration