Question

You took a fresh tomato and put it in a highly concentrated salt solution for 2 hr. Your little brother looked at it and stated, "The fat tomato is so thin now " What a magic?
(a) Define the phenomenon which has taken place.
(b) How does a cell wall help a plant to withstand hypotonic external media without bursting?

Answer 1

a) The phenomena which took place is known as exosmosis. Exosmosis is the movement of water outside the cell leaving the cell flaccid. When the tomato is placed in highly concentrated salt solution it shrinks. The salt concentration acts as a hypertonic solution due to which the water in the cells of tomato comes out in the concentrated salt solution by the process of exosmosis leaving the tomato flaccid.

b) A cell wall help a plant to withstand hypotonic external media without bursting as the cell takes the water by osmosis it swells and builds a turgor pressure the wall exerts an equal pressure against the swollen cell which is known as wall pressure. The turgor pressure is neutralized by wall pressure.