Download B1 Controlling plant growth

Controlling Plant Growth – Revision Pack (B1)
Plant Responses:
Phototropism is a plants growth response to light.
Geotropism is a plants growth response to gravity.
The shoot and roots of a plant behave differently.
The shoot is positively phototropic (grows towards the sun) and is
negatively geotropic (grows away from the force of gravity).
The roots are negatively phototropic (grow away from the sun) and
are positively geotropic (grow with the force of gravity).
Plant hormones:
Auxins are a group of plant hormones that are made in the root and shoot tip. They
move through the plant in solution. Auxins are involved in phototropism and
geotropism.
The amount of auxin varies in the shoot
when the tip is exposed to light.
More auxin is found in the shady parts of a
plant. A higher amount of auxins means
cell elongation. Therefore, the shady side
of the plant will increase its cell length
causing a curving shoot.
When the shoot tip is removed the shoot
doesn’t grow.
Commercial uses of plant hormones:
Plant hormones have many commercial uses, for example:
-
As selective weedkillers (will kill certain weeds and increase crop yield)
As rooting powder (to increase root growth of cuttings)
To delay/speed up fruit ripening (to meet demand)
To control dormancy in seeds
Controlling Plant Growth – Revision Pack (B1)
Past Papers:
PPQ(1):
Controlling Plant Growth – Revision Pack (B1)
PPQ(2):
Controlling Plant Growth – Revision Pack (B1)
PPQ(3):
Controlling Plant Growth – Revision Pack (B1)
PPQ(4):
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Controlling Plant Growth – Revision Pack (B1)
Controlling Plant Growth – Revision Pack (B1)
Mark Schemes:
PPQ(1)
PPQ(2):
Controlling Plant Growth – Revision Pack (B1)
PPQ(3):
PPQ(4):