PLANTS Flashcards
Name 4 stimuli plants can respond to
water sunlight gravity chemicals touch
name 3 plant hormones
auxins
givverelins
abscisic acid
what is a hormone
chemical messenger produced in one part of the plant and has an effect on another part of the stem
what is a tropism
growth or turning movement of a plant in response to an external stimulus
what are the 2 types of tropisms
phototropism
genotropism
compare phototropism and genotropism
photo: response to light
geotropism: response to gravity
What is unilateral light
light coming from one side or direction
what is the apical bud
growing point of the stem located at the tip of the stem
what is apical dominance
when auxins produced at the tip of the stem inhibit the growth of the branches closer to the tip of stem.
where are auxins produced
growing tips of stems.
what is the name of the most common auxin
indole acetic acid (IAA)
Functions of auxins
- apical dominance
- tropisms
- cell division
- develops flowers and fruits
what is apical dominance state
that the main central stem is dominant over other side stems
when does apical dominance occur
auxins produced at tip of stem result in the stem growing upwards and inhibits the growth of lateral branches.
explain the use of auxins in the fruit industry
plants kept short with more lateral branches = more fruit
fruit closer to ground = easier to pick
compare negative and positive tropism
negative = plant moves away from stimulus
positive = plant moves towards stimulus
compare uniform light and unilateral light
uniform - directly above
unilateral - 1 direction
advantages of phototrophism
leaves recieve light for photosynthesis
promotes pollination
easier seed dispersal
where is gibberellins produced
terminal buds of stems and roots in young leaves and in embryos
5 functions of gibberellins
stem elongation root growth flowering growth of lateral buds seed germination
what is abscisic acid
growth inhibitor that counteracts functioning of auxins, it plays a role in helping a plant cope under stress.
function of abscisic acid
- dormancy of terminal buds/lateral buds
- dormancy of seeds inhibits germination
- promotes abscission of leaves/fruits
- closing of Stoma during wilting
list 5 reasons why plant hormones are used in crop formation
- root formation in cuttings
- production of seedless fruit
- ripening of fruit
- increase in fruit Size
- stimulation of germination
list 2 types of plant defence
mechanical and chemical
name 3 types of mechanical defence
thorns
prickles
spines
how do chemical defences work
posions enemies by affecting feeding, growth and therefore survival
