All the physiological activities in the plant utilize water. Water is considered as an important constituent of all the living organisms. Water is an important solvent for many substances. Protoplasm in the cell consists of water in which many molecules are dissolved. Some of the fruits like watermelon are known to consist of 92 percent of water. About 10 to 15 percent of the fresh weight of the herbs seems to represent the dry material. The presence of water in plants varies based on the plant parts. The woody portion of the plant comprises of comparatively meager amounts of water than the soft portion of the plants. The seed of the plants appears dry though they possess some water in them. Water helps to retain life in the seed and helps it in respiration.
The land plants consume large amount of water every day while much of the water will be evaporated into the atmosphere through the leaves. This process of evaporation of water from the leaves into the environment is called as transpiration. It is estimated that an adult corn plant is found to be able to absorb nearly three liters of water every day. The mustard plant is known to consume an equal amount of water as that of its weight in a 5-hour duration. As water is necessary for plant growth, it is considered as the important factor essential for the productivity and growth of the plant.