NCERT Solutions Curiosity Chapter 10 .2.4 How do leaves exchange gases during photosynthesis? — Activity 10.6: Let us examine (demonstration activity)
Book page 14710 Updated on2026-09-05
Q1.
What do you observe? Do you notice tiny pores on the peel, as shown in Fig. 10.6?
Answer
Yes. Under the microscope the thin peel from the lower surface of the leaf looks like a sheet of closely fitted cells, and scattered among them are many tiny oval openings. Each opening is bordered by a pair of curved, bean-shaped cells.
These pores are called stomata (one pore is a stoma). In the rhoeo leaf of Fig. 10.6 they are about 0.1 mm across at the scale marked on the figure — far too small to see with the naked eye.
One stoma as it appears in the peel: a pore between two guard cells. Gases pass in and out of the leaf through thousands of such pores.
Why the ink and the lower surface: the ink does not stain the pores, so they stand out clearly against the darkened cells around them. The lower surface is peeled because most stomata of a broad leaf are on the shaded underside, where less water is lost.
Q2.
What are these pores called, and how do they help the plant?
Answer
They are called stomata. Stomata, present on the surface of leaves, help in the exchange of gases.
Process
Gas entering through stomata
Gas leaving through stomata
Photosynthesis (in sunlight)
Carbon dioxide
Oxygen
Respiration (all the time)
Oxygen
Carbon dioxide
Did you know? Water vapour also escapes from the leaf through the stomata. That is why a potted plant covered with a transparent polythene bag soon has drops of water inside the bag.