AP BIOLOGY

Detailed explanation-1: -Some common plant stimuli include light, gravity, water, movement of the sun, and touch. The naming of the tropism is associated with the stimulus. For example, the movement of plant roots towards water is called hydrotropism.

Detailed explanation-2: -Sensing Touch Plants have specialised sensory organs known as mechanoreceptors that detect mechanical stimulation like touch and pressure. Mechanoreceptors in plants often take the form of fine hairs.

Detailed explanation-3: -sensitive plant, (Mimosa pudica), also called humble plant, plant in the pea family (Fabaceae) that responds to touch and other stimulation by rapidly closing its leaves and drooping.

Detailed explanation-4: -When subjected to constant directional pressure, such as a trellis, plants move to grow around the object providing the pressure; this process is known as thigmotropism. Thigmonastic responses include opening and closing leaves, petals, or other parts of the plant as a reaction to touch.