5.1.5 Flashcards
Why is it important for plants to respond to their env?
avoid abiotic stress
avoid herbivory
maximise photosynthesis
help ensure germination
What is phototropism?
a plants growth repsonse to light
What is + phototropism?
growth towards light
Why does + phototropism happen>
to get max light for photosynthesis
What part of the plant does positive phototropism happen?
stem tip
What is negative geotropism?
growth away from light
Where does negative geotropism happen?
root tip
Why does negative getropism happen?
less chance of drying out
What is geotropism?
plants response to a plants growth response to earths gravitational field strength
What is positive geotropism?
plants grow towards gravitational attraction
What part of the plant exhibits negative geotropism?
shoots
What is hydrotropism?
Plant’s growth response to earth’s water
What part of a plant exhibits positive hydroptropism?
respond by growing towards water
What is thigmotropism?
plant’s growth response to touch
What is the Mimosa Puddica?
responds to to touch
What does the mimosa puddica do when touched?
leaves coil up
What is benefit of M.P leaves coiling up?
movement of leaves scares away herbivores
curling leaves less likely to be eaten
What are alkaloids?
bitter tasting
nitrogenous compounds
plants
What is caffeine?
compound
toxic to fungi and insects
What is nicotine?
toxin
prod in roots of tobacco plants
poisonous to many insects
What are tannins?
bitter-tasting and toxic compound
What do tannins do?
bind to digestive enzymes in saliva and inactivate them
What does the bitter taste allow?
puts animals off of eating the leaves?
What are terpenoids?
large group of compounds produced by plants
form essential oils
often acts as toxins
What are pheromones?
chemicals made by organisms that affect behaviour of other species
In an auxin exp, what would happen when…
tips are removed?
no auxin is made
as tip is where auxin is made
so no upwards growth of shoot / stems font grow
if more developed seedling, more lateral growth (side shoots)
In an auxin exp, what would happen when…
tips are covered?
auxin moves to all parts of the stem
all parts grow
In an auxin exp, what would happen when…
the tips are lit from one side ?
auxin accumulates on the shaded side
causing it to grow more than the illuminated side
What is a use of ethene?
control fruit ripening
What powder is auxin used in?
rooting
What is microppropogation useful for?
produce seedless plants
What is micropropogation?
apply root powder to shoots / leaves
to stimulate root growth
How do auxins stimulate shoot growth?
apical dominance
What aids quick growth in shoots?
cytokinnins
What is micropropogation?
applied to shoots /leaves of plant to stimulate root growth
What are the uses of auxins?
hormonal weedkillers
rooting powders
How are auxins used as weedkillers?
promotes growth in broad leaved weeds so they cannot support themselves and die
so narrow leaved crops can grow without competition
What is good about auxins as weedkillers?
cheap
less harmful to env
What are the uses of gibberelins?
delay ripening / age in fruit
produce malt
GERMINATION OF SEEDS
improves fruit shape and size
What do cytokinins do?
prevent ageing in ripened fruit
What does a lack of auxin, cytokinins and gibbeilerins cause?
aid fruit dropping
What does ethene preserve?
cut flowers and green veg
