Crossword clues for phototropism
phototropism
The Collaborative International Dictionary
Phototropism \Pho*tot"ro*pism\, n. [Photo- + Gr. ? to turn.]
(Plant Physiol.) The tendency of growing plant organs to move or curve under the influence of light. In ordinary use the term is practically synonymous with heliotropism.
(Microbiology) exhibiting movement in a direction toward ( positive phototropism) or away from ( negative phototropism) a source of light.
Douglas Harper's Etymology Dictionary
Wiktionary
n. (context biology English) the movement of a plant towards or away from light
WordNet
n. an orienting response to light
Wikipedia
Phototropism is the growth of an organism which responds to a light stimulus. It is most often observed in plants, but can also occur in other organisms such as fungi. The cells on the plant that are farthest from the light have a chemical called auxin that reacts when phototropism occurs. This causes the plant to have elongated cells on the farthest side from the light. Phototropism is one of the many plant tropisms or movements which respond to external stimuli. Growth towards a light source is called positive phototropism, while growth away from light is called negative phototropism. Most plant shoots exhibit positive phototropism, and rearrange their chloroplasts in the leaves to maximize photosynthetic energy and promote growth. Roots usually exhibit negative phototropism, although gravitropism may play a larger role in root behavior and growth. Some vine shoot tips exhibit negative phototropism, which allows them to grow towards dark, solid objects and climb them. The combination of phototropism and gravitropism allow plants to grow in the correct direction.
Usage examples of "phototropism".
Sun in its course across the sky was evidence of a literal miracle before we knew about phototropism and plant hormones.
Because we know something about phototropism and plant hormones, we can understand the opening of the morning glory independent of divine microintervention.
This plant exhibits a highly sophisticated degree of negative phototropism.
The fact that we cannot now produce a detailed understanding of, say, altered states of consciousness in terms of brain chemistry no more implies the existence of a `spirit world' than a sunflower following the Sun in its course across the sky was evidence of a literal miracle before we knew about phototropism and plant hormones.
The fact that we cannot now produce a detailed understanding of, say, altered states of consciousness in terms of brain chemistry no more implies the existence of a 'spirit world' than a sunflower following the Sun in its course across the sky was evidence of a literal miracle before we knew about phototropism and plant hormones.