Question

Explain why xylem transport in unidirectional and pholem transport bi directional ? Name two substamsuthat are transported through xylem?

Answer 1

During the growth period of the plant, the leaves act as a photosynthetic unit and carry out the process for formation of food and serve as source and the phloem carry the formed food from source to the area of growth or storage called a sink. While during spring seasons, this process gets reversed as the food stored in the sink is mobilized to the region of growing buds of the plants through the phloem. This is the reason why the bidirectional flow of material is observed in the phloem.

The transport of water through xylem has to take place from roots to leaves only thus it is meant to be unidirectional.

The two substances transported by the xylem are water and minerals.