controlling plant growth Flashcards
(23 cards)
what is a giberellin
hormone
promote seed germination
promote stem growth
what is auxin
regulate plant growth
inhibit leaf fall
found in apical bud
prevent lateral buds from growing
what is apical dominance
inhibition of lateral buds further down the shoot by chemicals produced by the apical bud at the tip of the plant shoot
where is the apical meristem
at the tip of the plant
where is the intercalary meristem
in the middle of the plant
where is the lateral meristem
at the lateral areas of the plant
what happens to the growth of a plant when you break the apex off
side branches grow from lateral buds that were previously dormant (resting).
how do gibberellin promote seed germination
when seed absorbs water, the embryo releases giberellin which then travels to the endosperm region of seed. The giberellin produces amylase breaking down starch into glucose.
the glucose is then a respiratory substrate for the embryo.
where are auxins found in the plant
apical bud
if auxins are present in the apical bud of a plant, if you break the tip of a plant off what happens
tip is removed
auxin levels drop
lateral buds begin to grow
because auxins prevent lateral buds growing
how did scientists test if auxins prevent lateral bud growth
apply a pasta containing auxins to the cut end of a shoot and lateral buds didnt grow
what did scientists conclude about the effects of high auxin levels and low auxin levels
suggested that normal auxin levels prevent lateral bud growth
low auxin levels promote lateral bud growth.
what experimental evidence proved that high level of auxins maintain apical dominance
auxin production in apex maintains high levels of abscisic acid.
both inhibit growth of lateral buds
when apex of shoot is removed, auxin levels drop, abscisic acid levels fall
cytokinins diffuse through plant evenly now apex is gone
promoting lateral bud growth
what is apical dominance
inhibition of lateral buds further down the shoot by chemicals produced by apical bud at apex (top) of shoot
what chemicals override apical dominance
cytokinins
does abscisic acid inhibit or promote bud growth
inhibit
what is a meristem cell
stem cell for a plant, capable of continuous cell division by mitosis
pluripotent
what does ethene do
promote fruit ripening
what do cytokinins do
overcome apical dominance
promote cell division
promote cell expansion
what does abscisic acid do
cause stomatal closure when plant is stressed due to low water availability
inhibit seed germination and growth
help maintain apical dominance
how do giberellins promote seed germination
when germinating seeds absorb water, embryo releases giberelling, which enables production of amylase (digest starch to glucose for respiratory substrate).
embryo grows.
added auxin to the natural production can inhibit..
root growth
when giberellins and auxin are added to a plant, it grows taller and has shorter roots why
because giberellins promote stem elongation
excess auxin can inhibit root growth
