Class 11 NEET Biology Plant Growth and Development

(c) : The growth movement in response to touch, or contact of a foreign body, in plants is called thigmotropism or thigmotropic movement. The stems and tendrils of the climbers are positively thigmotropic in their response. The coiling of garden pea tendrils around any support is an example of thigmotropism. Thigmonastic (haptonastic) movements are induced by some external stimuli. For example tentacles of Drosera leaf curve and the lamina lobes of Dionaea fold on coming in contact with an insect.