Plant Signals

Question 1

what is etiolation?

Answer 1

when potatoes grow up until sense light and then grow down

gravity/light have similar effects

Question 2

what is transduction?

Answer 2

tiny light falling on sprouts triggers root growth

receptor proteins influenced by environmental stimulus - regulation of secondary signalling hormones

Question 3

function of auxin?

Answer 3

elongation
behind shoot tip, grow towards light
drive phototropism

Question 4

conseuences of reduced auxin?

Answer 4

reduced growth
triggers leaf production/shedding
controls development of leaf veins
reduced investment in roots/water transport

Question 5

function of gibberellins?

Answer 5

cell elongation with auxin

released during water absorbtion

Question 6

function of ethylene?

Answer 6

ripening

thickens plants so they can grow around to avoid an obstacle

Question 7

effect of fungal parasites on plants?

Answer 7

trade off against nutrient collection

PAMP triggered immunity - local production of antimicrobial chemicals

Question 8

defences against herbivory?

Answer 8

molecular - tannins
cellular - raphites
tissue - thick cell walls
organs - spines
organismal - timing of flowers

Question 9

how do plants deal with dry environments?

Answer 9

succulence
annual
spines and hairs reduce direct sunlight
drop leaves, small leaves, waxy surface with few stomata

Question 10

how do plants cope with flooding?

Answer 10

hollow stems

air spaces - buoyancy and storage of oxygen

Question 11

how do plants cope with salty soils?

Answer 11

salt in ground water leaches from roots to surrounding soil causing dehydration
halophytes have high salt concentrations to reverse this