The growth of the parts of plants with respect to the force of gravity. The upward growth of plant shoots is an instance of negative geotropism; the downward growth of roots is positive geotropism.
- ‘It was shown that gaseous ethylene inhibits both growth and geotropism in plants, and ethylene is endogenously produced by fruits.’
- ‘Transversal geotropism is a direction of growth that is vertical to the shoot axis.’
- ‘This is the best way to maximize grow space, minimize power consumption, and utilize geotropism to spread growth auxins throughout the plant.’
- ‘To account for the positive geotropism of roots, some researchers have proposed that under the influence of gravity, starch grains within the cells of the root fall towards the bottom of the cell.’
- ‘Geotropism occurs in two forms: positive geotropism to which the root responds by growing downward; and a negative geotropism, which causes the stem to grow upward.’
Late 19th century: from geo- ‘earth’ + Greek tropē ‘turning’ + -ism.
We take a look at several popular, though confusing, punctuation marks.