There are three plants A, B and C. The flowers of plant A open their petals in bright light during the day but close them when it gets dark at night. On the other hand, the flowers of plant B open their petals at night but close them during the day when there is bright light. The leaves of plant C fold up and droop when touched with fingers or any other solid object.
(a) Name the phenomenon shown by the flowers of (i) plant A, and (ii) plant B.
(b) Name one flower each which behaves like the flower of (i) plant A, and (ii) plant B.
(c) Name the phenomenon exhibited by the leaves of plant C.
(d) Name a plant whose leaves behave like those of plant C.
(e) Which plant/plants exhibit the phenomenon based on growth movements?
(a) (i) Plant A shows positive photonasty.
(ii) Plant B shows negative photonasty.
(b) (i) In the morning, a dandelion flower opens up its petals in bright light. This phenomenon is known is positive photonasty.
(ii) A Moonflower flower closes its petals at night. This phenomenon is known as negative photonasty.
(c) Thigmonasty is the non-directional movement of a plant part in response to the touch. The folding up of leaves of plant C when touching is an example of this process.
(d) The folding up of Mimosa pudica leaves when touching is an example of Thigmonasty process.
(e) Plant A and B exhibit the phenomenon based on growth movements.