Question

What is the role of diffusion in plants?

Answer 1

Diffusion is the process of movement of solute or solvent molecules in accordance with the concentration gradient that is from the region of higher concentration to its region of lower concentration. It plays an essential role in respiration in plants and animals.

Complete answer:
The plants absorb water and minerals from the soil. This water and minerals are taken up by all the parts of the plant. These water and minerals are transported through the xylem vessels by the process of diffusion.

Diffusion is the movement of molecules from higher concentration to the lower. The molecules can be solute, solvent or even gaseous.

1)In plants the diffusion of molecules takes place across the membrane. It does not require any energy. The diffusion can be facilitated through some channel proteins or transporter.
2)The diffusion is the driving force for the gaseous exchange during photosynthesis. The carbon dioxide concentration is greater outside than that of the leaves. So the carbon dioxide diffuses from the atmosphere to the cell when the stomata is open. The oxygen concentration in the leaves is greater so it diffuses out to the atmosphere.
3)The food prepared by the plant is transported by the phloem by the process of diffusion.
4)The transpiration is also caused due to diffusion. The water vapour (by product of photosynthesis) diffuses out to the atmosphere.
5)The smell of the flowers diffuses in the atmosphere which helps in pollination by attracting insects.

Note: The factors which affect the rate of diffusion are:
1)Temperature- Rate of diffusion is greater at higher temperature.
2)Density- Rate of diffusion increases with the decrease in density. Diffusing rate of gas is greater than that of solutes.