M5 plant responses Flashcards
what are alkaloids?
chemicals with bitter taste, noxious smells or poisonous characteristics that deter or kill herbivores
what are tannins?
taste bitter and can bind to protein in gut making the pant hard to digest deterring animals from eating the plant
what are pheromones?
signalling chemicals that produce a response in other organisms as some plants release alarm pheromones into the air in response to herbivore grazing. Caterpillars produce pheromones which attract parasitic wasps that lay eggs in caterpillars which eventually kills them.
what is phototropism?
is the growth of a plant in response to light
what is geotropism?
growth of a plant in response to gravity
what are 2 example of a growth hormone?
gibberellin
auxin
what is the role of giberellin?
stimulates seed germination, stem elongation, side shoot formation and flowering
what is the role of auxin?
stimulate the growth of shoots by cell elongation, high levels of auxin inhibits growth in roots
what is apical dominance?
auxins stimulate the growth of the apical bud and inhibit the growth of side shoots from lateral buds , prevents side shoots from growing
how are auxin and gibberellins synergistic?
they both work together to help plants grow very tall
how are auxin and gibberellins antagonistic?
gibberellins stimulate the growth of side shoots whereas auxins inhibit the growth of side shoots
what are deciduous plants?
plants that lose their leaves in the winter (abscission)
which hormone inhibits leaf loss?
auxins
auxins are produces by young leaves, as a leaf gets older, less auxin is produced and this leads to leaf loss
which hormone is involved in stomatal closure?
abscisic acid ABA
what is a commercial use of ethene?
the fruit industry uses ethene to ripen bananas
