Plant Hormones Flashcards
Advantages of positive gravitropism(upwards)?
More light absorbed.
More photosynthesis.
More glucose is produced.
Plant will be able to grow more.
The flower would attract insects, rate of seed dispersal will increase.
Advantages of negative gravitropion (downward)?
Better anchorage for the ☘️.
Able to absorb water and ions more.
Advantage of phototropism?
Larger surface of the cell is exposed(bends towards light).
More sunlight is absorbed.
Higher rate of photosynthesis. More glucose is produced.
Synthesise s w/ absorbed nitrates.
Amino acids produced.
New protoplasm formed.
Increased growth.
How do auxins control growth response?
Auxins stimulate cell elongation.
Produced at tip.
Cells have turgor pressure.
Causes cells to lengthen.
Auxins accumulate on the shaded side.
More growth on the shaded side causes it to bend.
In roots, auxins accumulate on the lower side and inhibit growth.
Cells on the upper side grow faster. Root curves downwards.
Describe an experiment to show auxin causes bonding of a shoot?
paint auxin on one side of shoot (or description of other suitable treatment) ;
place shoot in a dark place AW ;
leave + for stated period of time (e.g. 1 to 3 days) / until the shoot
to grows vertically / changes direction AW ;
ref. to control without auxin ;
ref. to repeats used ;
Explain the mechanism that results in a shoot bending towards the light?
auxin accumulates on shaded side of shoot
auxin is broken down by light ;
difference in concentrations on shaded side and light side ;
cells with higher concentration of auxin absorb more water ;
causes unequal growth ;
Describe how synthetic plant hormones are effective as weedkillers?
to large concentrations used ; plants / leaves / stems + are stimulated to grow rapidly ;
growth gets out of control ;
root growth inhibited by high concentrations of auxin ;
so plants die
only broad leaved plants affected
