Question

The rate of transpiration is more in hot and sunny day because_

Answer 1

Hint: Transpiration may be defined as a process of water movement through a plant and its evaporation from the parts like leaves. This process carried in leaves where stomata open passage for carbon dioxide as well as oxygen for photosynthesis.

Complete answer:
1.Leaf surfaces are dotted with pores known as stomata which are bordered by guard cells and accessory cells that open and close the pore.
2.Transpiration is a process of cooling plants, changing osmotic pressure of cells and enables mass flow of mineral nutrients as well as water from roots to shoots.
3.Number of leaves-More leaves means bigger surface area and more stomata which result in more gaseous exchange.
4.Size of leaf-Leaf with a bigger surface area will transpire faster than with a small surface.
5.Temperature-An increased rate of evaporation due to a temperature rise hastens the water loss.
6.Water supply-Water stress caused by restricted water supply from soil results in reduced rates of transpiration due to stomatal closure.
A leaf transpires many times more water than its own weight during a growing season. Plants transpire more in sunny and hot days due to rise in temperature and because of this plants transpire as water evaporates rapidly. At the temperature of 30 degree transpiration in leaves is three times more.

Note: Transpiration rates of plants can be measured by a number of techniques called lysimeters, photometers, porometers, thermometric sap flow sensors.