2.80 Geotropism

2.80 describe the geotropic responses of roots and stems

Geotropic

Geo; gravity

Tropic; growth response

Therefore is the growth response to gravity.

For example if we experiment a germinating seed, when observing the growth one finds that the embryonic roots are grown downwards, this is known as positive geotropism.

Whereas the shoot will grow upwards to the soil surface. This is known as negative geotropism.

If we experiment further by taking the same seed however rotating it 90 degrees to the left, we find that the shoot grows upwards (negative geotropism) and the root grows downwards (positive geotropism).

Below is a diagram showing the experiment described above: