AP BIOLOGY

Detailed explanation-1: -Some of the most spectacular plant movements are nastic movements. These include the closing of the carnivorous Venus Flytrap leaf when it captures prey or the folding of the mimosa leaf when it is disturbed.

Detailed explanation-2: -The “trap” is made of two hinged lobes at the end of each leaf. On the inner surfaces of the lobes are hair-like projections called trichomes that cause the lobes to snap shut when prey comes in contact with them. This type of movement is called thigmonasty-a nondirectional plant response to being touched.

Detailed explanation-3: -Nastic movements are non-directional responses to stimuli (e.g. temperature, humidity, light irradiance), and are usually associated with plants. The movement can be due to changes in turgor. Decrease in turgor pressure causes shrinkage while increase in turgor pressure brings about swelling.

Detailed explanation-4: -The insect-trapping movement of the plant Dionaea muscipula (Venus’s fly-trap) is mediated by the stimulation of mechanosensory hairs located on the surface of the trap. It is known that stimulation of the hairs is followed by action potentials which are propagated over the surface of the trap.