Q.12: What are the differences between the transport of materials in xylem and phloem?
Xylem and Phloem are two types of vascular tissues for the transport of substances in plants. The differences in the transport of materials are summarized below:
|1. Xylem conducts water and dissolved mineral from roots to leaves and other part.
2. In xylem, transport of material takes place through vessels and tracheids which are dead tissues.
3. In xylem, upward movement of water and dissolved materials is mainly achieved by transpiration pull. It is caused due to suction created by evaporation of water molecules from the stomata of a leaf.
4. Movement of water is achieved by simple physical forces. There is no expenditure of energy. So, ATP molecules are not required.
|1. Phloem conducts prepared food material from leaves to other parts of plant in dissolved form.
2. In phloem, transport of material takes place through sieve tubes with the help of companion cells, which are living cells.
3. In translocation, material is transferred into phloem tissue using energy from ATP. This increases the osmotic pressure that moves the material in the phloem to the tissues which have less pressure.
4. The translocation in phloem is an active process and requires energy. This energy is taken from ATP.