Question

P and Q are two types of plants having weak stems which cannot stand upright on their own. The plants P and Q have organs R and S respectively which can grow towards any support which they happen to touch and wind around that support. It is observed that organ R originates from the leaves of the plant whereas organ S originates directly from the stem of the plant.
(a) What is (i) R, and (ii) S?
(b) What is the name of growth movement exhibited by the organs R and S?
(c) Name the stimulus involved in this case.
(d) State whether the behaviour of organs R and S is a tropic movement or a nastic movement.
(e) Name one plant like P and another plant like Q.

Answer 1

(a) (i) R is a leaf tendril and (ii) S is a stem tendril.
(b) The growth movement exhibited by R and S is thigmotropism.
(c) The stimulus involved is touch or contact with other objects.
(d) The behaviour of R and S is a tropic movement.
(e) Pea plant is an example of plant type P, whereas bitter gourd plant is an example of the type Q.