Plant hormones (triple only) Flashcards
Plant shoots show positive phototropism.
In which direction will the plant shoot grow?
Towards the light
How do plant coordinate and control growth and responses?
Produce hormones
Plants respond to gravity.
What is this response called?
Gravitropism or Geotropism
Name the plant hormone responsible for tropisms
Auxin
Name the hormone that initiates seed germination
Gibberellins
What effect does ethene have on plant growth?
Controls cell division
Controls ripening of fruits
Give 3 uses of auxin in agriculture and horticulture
Weedkiller
Rooting power
Promoting growth in tissue cultures
Give a use of ethene in the food industry
Control ripening of fruit during storage and transport
Give 3 uses of gibberellins
End seed dormancy
Promote flowering
Increase fruit size
What is a tropism?
A growth response of a plant to a specific stimulus
What is phototropism?
Growth response of a shoot or a root to light
What is gravitropism or geotropism?
Growth response of a shoot or root to gravity
Describe how auxin causes phototropism in a shoot
Auxin is made in the shoot tip
Auxin is transported to the shaded side of the shoot
Unequal distribution of auxin causes unequal growth
Shaded side grows faster
Shoot grows towards the light
How do plant shoots show negative gravitropism or geotropism?
In a horizontal shoot auxin accumulates in the lower side
Cells on the lower side of shoot grow quicker
Shoot bends away from gravity
How do plant roots show positive gravitropism?
In a horizontal root, auxin accumulates on the lower side
These root cells grow less rapidly
Root bends in the direction of gravity
