Tropism - GCSE Biology Definition

Tropism is a biological term that describes how plants respond to different stimuli by growing towards or away from them. For example, plant shoots often grow towards light, which is known as positive phototropism. This helps them get more sunlight for photosynthesis, which they need to make food. Another type is gravitropism, where roots grow downwards (positive gravitropism) and stems grow upwards (negative gravitropism) in response to gravity. Tropisms can also involve responses to water (hydrotropism) and touch (thigmotropism). These growth responses help plants survive in their environments by helping them access important resources like light and water.