the.com/phototropism
Plants aren't reaching for the sun, they're growing away from their own shaded side.
means The tendency of a plant (or other organism) to grow or bend toward — or sometimes away from — a source of light.
from Built from Greek roots: 'photo-' meaning light, and 'tropos' meaning turn — the same 'tropos' that gives us 'trope.' Coined in the 19th century as botanists building the vocabulary of plant behavior needed a word for light-driven turning, pairing it with siblings like 'geotropism' (response to gravity) and 'hydrotropism' (response to water).
- the mechanism
- auxin hormone piles up on the shady side, elongating it
- lopsided growth
- uneven cell elongation bends the stem toward light
- discovered by
- Darwin and his son, studying grass seedlings in 1880
- the receptor
- phototropin proteins detect blue light specifically, not all colors