Phototropism

Phototropism at Caverna Laje Branca

The directional growth of a plant in response to the stimulus of light is known as phototropism. It is a permanent, positive or negative change, in the position of a plant part. The different classifications of plant movement are either autonomous or induced movements. While autonomous movement has no detectable external cause, induced movement is a stimulus response. This is further organized as nastic responses and tactic movements. A nastic response is non-direction, such as temperature or humidity, whereas a tactic movement has a directional orientation, such as light and gravity.