Plant water relations are essential for plant growth and metabolism. Water is absorbed by plant roots and transported throughout the plant. Water has unique properties that make it suited for its functions in plants. It has a high heat of vaporization, surface tension, and ability to dissolve nutrients. These properties allow water to move within plants and play important roles in processes like photosynthesis, transpiration, and nutrient absorption. Water is critical for many plant physiological processes and is necessary to sustain life for both terrestrial and aquatic plants.

1. Plant water relations
Dhole N. A.
Department of Botany,
Digambarrao Bindu ACS College, Bhokar

2. Introduction:
• Water is most important factor for growth, development and all
metabolic process of plant
• All terrestrial plants absorbs water and minerals from the soil by
their root system.
• The root differentiated into three regions, in which root hairs region
helps in the absorption of water.
• The absorbed water minerals is transported to upper parts of the
plant.
• The absorbed water is also vaporized through the aerial parts of
plant such as stomata, cuticle and lenticular transpiration.
• The phenomenon such as osmosis, diffusion, imbibition and
plasmolysis are totally depends on water.
• In soluble forms of all essential and non-essential nutrients are
absorbed by plants which is because of water.

3. Structure and properties of water:

5. • The pure water is colorless and odorless liquid.
• The melting point of water is 0 °C and boiling point is 100 °C .
• The maximum density of water is at 4 °C.
• The latent heat of water is higher than other liquids. (Latent heat: The
energy required to convert liquid water into gas or vapor at constant
temperature.
• Water expands as it freezes and its density decreases. Ex. Ice floats on
river or in oceans.

6. • Cohesive forces of water is very high. (The attraction of molecules
between similar molecules)
• Adhesive forces of water is also high. (The attraction of molecules
between dissimilar molecules).
• Water has high water tension.
• Water is polar solution.
• Water shows liquid, solid and gas state.
• Water is universal solvent.

7. Importance of water to plant life:
• Life of living organism is impossible without water. In plants, each &
every metabolic pathway requires water.
• The colorless properties of water have high importance in hydrophytic
plant life because it allows the light easily for their photosynthesis
process.
• Water required more energy to rise its temperature this property of
water has great importance to plants life in protecting them from high
temperature.
• The conversion of water to vapor from required high energy, this
property enables plant to protect from loss of water in the form of
vapor.
• Water has high importance in plant life because it expands at freezing
point and density decreases. Therefore ice can floats on water and
protects life present in ocean, etc.

8. • Cohesive and adhesive properties of water are of great importance in
absorption and transport of water from base to apex of plant.
• High surface tension of water is responsible for transpiration pull that
facilitates rising up water in higher plants.
• Water is excellent solvent and provide medium for dissolving variety of
substances than other solvents.
• It also helps to the movement of molecules within cell and between two
cells.
• Most of all biochemical reactions of the cell take place in water such as
hydrolysis, hydration and dehydration etc.

9. • Water is essential for the photosynthesis.
• Water helps to maintain the temperature of plant by transpiration.
• Water helps to absorbs minerals (Major and minor).
• In lower and higher plants, water requires for fertilization process.
• Water also helps for dehiscence of sporangia, seed dispersal and
pollination in many plants.
• Water produces many physiological processes in plants such as cell
enlargement, translocations of food material, maintaining the shape of
cell, seed germination, seed emergence etc.
• Water is very important for opening and closing of stomata.

10. Thank you