Slides in this set
Phototropism The movement of plants in
response to light.
If exposed to unilateral light:
the shoot will bend towards it.
the roots will grow away from it.
Shoots = positively Roots = negatively
This tropic response helps to
ensure that shoots receive as
much all-round light as possible,
allowing the maximum amount of
photosynthesis to take place.…read more
Once the tip is removed, upward growth stops.
When the tip is replaced, growth begins again.
Conclusion: The tip of a shoot exerts an influence on
the region of growing cells behind it.…read more
(Just behind the tip)
The shoot stops growing on the side that the
blade is inserted.
The shoot bends over.
Conclusion: The signal from the tip is blocked by the
razor blade; likely to be chemical.…read more
(Left for several Shoot bends
Decapitated shoot doesn't grow.
Normal growth resumes when agar is places on
Conclusion: A chemical message is produced in the tip,
which diffuses down into the agar and then diffuses into the
rest of the shoot, stimulating normal growth.…read more
The side with the agar block grows more than
the other side.
The shoot bends away from the stimulated side.
The Went Bioassay The amount of
chemical messenger in the agar
block can be used to measure the
biological activity of the messenger