TRANSPORTATION IN PLANTS
Suminder kaur, Academic Content Writer at Edumarz
Photosynthesis requires a variety of raw materials. Plants take in CO2 through their stomata, which diffuses into their cells, and they take in nitrogen, phosphorus, and other minerals through their roots.
Because the distance between the soil and the leaves is more. So, the diffusion mechanism alone isn’t enough to get these basic elements to the leaves.
Therefore, a proper transporting system is required for transportation in plants.
Plants require less energy as they do not move.
Plants two conducting tissues that help in transportation.
Xylem- moves water & minerals from roots to the leaves. And phloem is responsible for movement of food from leaves to other parts of the body.
These two tissues extend throughout the body of the plant.
XYLEM
Xylem is a specialized vascular tissue in plants.
It is a complex tissue that consists of 4 basic types of cells namely: tracheids, xylem vessels, xylem parenchyma and xylem fibre.
The only living component of xylem is xylem parenchyma.
Xylem transports unidirectional i.e from roots to leaves only (upward direction).
Water and minerals enter the roots by diffusion.The suction force created by transpiration then aids in the upward transport of water and minerals.
The water then travels through the plant to reach the leaves. This is called Ascent of sap.
PHLOEM
Food (carbohydrates and sugars) is transported from the leaves to the rest of the plant. This is referred to as translocation.
Phloem is also a complex tissue that is composed of four basic types of cells namely: sieve tubes, companion cells, phloem fiber and phloem parenchyma.
The only dead component of phloem is phloem fibre.
Phloem tissue works bi-directional i.e both in upward and downward direction and takes place in sieve tubes with the help of companion cells.