T5 plant hormones Flashcards
what is tropism
response of a plant to a specific stimulus
what is phototropism
response of a plant’s shoot or root to light
what is gravitropism
response of a plant’s shoot or root to gravity
what is auxin
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 also 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 on the lower side 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
type of plant hormone involved in seed germination
what is ethene
type of plant hormone involved in cell division and ripening
what are the uses of auxins
weedkillers - causes cells to grow at a rapid rate, causing plant death
rooting powder - causes new plant to grow very quickly
tissue culture - promotes growth of roots and shoots
uses of ethene
control of food ripening in the food industry - allows fruit to be ripened just before they are sold
uses of gibberellins
termination of seed dormancy
promotion of flowering
increase of fruit size
