Co-ordination and response in fLOWERING PLANTS Flashcards
Topic 2 J .2
plants need to be able to grow in response of certain stimuli, what is an example of this
in response to light, for photosynthesis
plants need to be able to grow in response of (2)
light and gravity
directional growth responses made by plants in response to light and gravity are known as ____
tropisms
tropisms are
directional growth responses made by plants in response to light and gravity
growth toward stimuli means the tropism is
positive
growth away from stimuli means the tropism is
negative
a response to light is called
a phototropism
a response to gravity is called
a geotropism
as shoots grow upwards, away from gravity and towards light,
is the phototropism positive or negative ?
AND
is the geotropism negative or positive
phototropism is positive
geotropism is negative
As roots grow downwards into the soil, away from light and towards gravity,
is phototropic response negative or positive ?
AND
is the geotropic response negative or positive
geotropic response is positive
phototropism is negative
plants produce plant growth regulators called
auxins
what do auxins do
coordinate and control directional growth responses such as phototropisms and geotropism
auxin is made where
in the tips of growing shoots
where do auxins travel to, and how do they get there
down to the region where cell division occurs by diffusion
which part of the shoot is able to grow by cell division and elongation
ONLY the region behind the tip of a shoot
auxin stimulates …
the cells in this region to elongate
the more auxin there is …
the faster the cells will elongate and grow
If light shines all around the tip, auxin is distributed
evenly throughout
If light shines all around the tip, cells in the shoot grow at (rate)
the same rate
When light shines on the shoot predominantly from one side, the auxin produced concentrates where
on the shaded side, making the cells on that side elongate and grow faster than the cells on the sunny side
unequal growth on either side of the shoot due to unequal light coverage causes shoot to ____ and grow in the direction of _____
bend
light
why is it important that shoots grow towards light
that increases the surface area that is exposed to light for photosynthesis
what are auxins
plant growth hormones
what does auxin affect and how
the growth of plants
by stimulating or inhibiting cell elongation
