4.5.4 Plant hormones (will come up) P2 Flashcards
What is a tropism
The response of a plant to a specific stimulus
What is phototropism
The response of a plant’s shoot or root to light
What is gravitropism
The response of a plants shoot or root to gravity
What is auxin
A hormone which controls the growth of a plant’s shoots and roots
When auxin is unevenly distributed in a growing plant, the rate of growth will be unequal
How do plant shoots show positive phototropism
One side of the shoot is in the light, causing auxin to move to the shaded side
At the shaded side, the cells are stimulated to grow
The shoot bends towards the light
As a result photosynthesis can occur at a faster rate
How do plant shoots show negative gravitropism
In a horizontal shoot, auxin accumulates in the lower side due to gravity
Cells of the lower sides of shoot grow more causing the shoot to bend away from the direction of gravity
As a result more light is usually available for photosynthesis
How do plant roots show positive gravitropism
In a horizontal root auxin accumulates in the lower side causing cells to grow less
The root bends in the direction of gravity
As a result more water and nutrients are available to the plant roots
What are gibberellins
A type of plant hormone involved in seed germination
What is ethene
A type of plant hormone involved in cell division and ripening
