Question

Question 31:
Why is the folding up of the leaves of a sensitive plant on touching with a finger not a tropism ?

Lakhmir Singh Biology Class 10

Answer 1

Answer:

Tropism is a growth movement.

but when we touch the leaves of sensitive plant it start folding because of the water present on the leaves start going from there.

in this process there is no change in the growth of the plant so it isn't tropism.

Answer 2

Explanation:

Because sensitive plant have swollen petioles called pulvinus. which holds water on touching leaves water flows from pulvinus to veins causing leaves to fold and after sometime these water gets recollected on pulvinus again...So folding and opening of leaves are based on water concentration not on tropism. ex of such plant is Touch me not (Mimosa pudica)