Paheli noticed water being pulled up by a motor-pump to an overhead tank of a five-storeyed building. She wondered how water moves up to great heights in the tall trees standing next to the building. Can you tell how?
Ans)
The motor pump generates a continuous suction pull due to which water from a lower height can be pulled up to an over –head tank of a five storey high building.
Explanation : The leaves in the tall trees by selectively keeping their stomatal pores open, generate water loss from the leaves’ surface through evaporation. Continuous evaporation creates a difference in water concentration between the roots and the leaves thus establishing a steep transpiration gradient. Suction pull comes into action forcing xylem vessels to transport water up to the leaves no matter what the height of the tree may be.This is how water is reached to the leaves of tall trees.