Name: Complex Tissues (Xylem and Phloem)
Uploaded: 2019-07-19
Duration: 6 min 10 s
Description: The average height of a coconut tree is 30 m. How does a coconut tree move water from its roots to the very tips of its leaves? Is it magic, or is it science...

Question

Xylem transports water upwards only whereas phloem transports food in both upward and downward directions. Why?

Accepted Answer

The loss of water through the aerial part of the plant is known as transpiration. It occurs mainly through the stomata, present on the surface of the leaves. It helps in the upward movement of water and minerals from roots to the leaves by generating a suction pull.

Xylem transports water and minerals from the roots to all the other plant parts. It transports sap upwards only because all other parts of the plant are in the upward direction. Therefore, the movement of water and minerals in the xylem is unidirectional.

Phloem transports food prepared by the leaves in both upward and downward directions, as each part of the plant needs energy food. Since the leaves located above performs photosynthesis and prepare food, it needs to be travelled to all other parts of the plant. Therefore, the movement of food in phloem is bidirectional.

Xylem transports water upwards only whereas phloem transports food in both upward and downward directions. Why?

Important Questions on Transport of Substances in Animals and Plants

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