plant hormones

plant hormones

auxin is a plant hormone that controls growth near the tips of shoots and roots. it controls the growth of a plant in response to light (phototropism), gravity (geotropism) and moisture
SHOOTS AND LIGHT: 1. when a shoot tip is exposed to light, more auxin accumulates on the side that is in the shade than the side which is in the light. 2. this makes the cells elongate faster on the shaded side, so the shoot bends towards the light
SHOOTS AND GRAVITY: 1. when a shoot is growing sideways, gravity produces an unequal distribution of auxin in its tip, with more auxin on its lower side. 2. this causes the lower side to grow faster, bending the shoot upwards
ROOTS AND GRAVITY: 1. a root growing sideways will also have more auxin on its lower side. 2. but in a root the extra auxin inhibits growth. this means the cells ontop elongate faster, and the root bends downwards
ROOTS AND MOISTURE: 1. an uneven amount of moisture either side of a root produces more auxin on the side with more moisture. 2. this inhibits growth on that side, causing the root to bend in that direction, towards the moisture.

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	Created by rozwald1205 about 10 years ago