Question

If a potted plant is covered with a glass jar, water vapours appear on the wall of the glass jar. Explain why?

Answer 1

Hint: In plants, transport of water occurs from the roots to the shoots by the help of xylem cells. The leaves contain stomata which removes excess water from it. Removal of excess water from the leaves is known as transpiration and guttation.

Complete answer:
The plants are known as autotrophs as they make their own food by the process of photosynthesis. Roots provide water to all parts of the plant. Leaves use very less amount of water for food production and excess water gets removed from the leaves. This process of removal of water from the leaves is called transpiration.

If a potted plant is covered with a glass jar, due to the process of transpiration water vapours appear on the wall of the glass jar.

Stomata present in the leaves perform gaseous exchange and also remove excess water through it. It is bordered by guard cells and their stomatal accessory cells that open and close the pore. Stomatal apertures help in this process. Plants regulate the rate of transpiration by regulating the size of stomatal apertures. It also depends on the evaporative demand of the atmosphere surrounding the leaf.

Note: Transpiration helps plants to maintain internal temperature and also changes osmotic pressure of the cells and enables mass flow of mineral nutrients and water from roots to shoots. The pressure gradient and hydrolytic activity are responsible for the flow of water in the plants. Capillary action also plays an important role in this. The vascular cells which transport water from roots to shoots are called xylem.