Plant Water Relations: Absorption, Transport and Control

What Are Plant Water Relations?

Plant water relations entail investigating how plants regulate the intake, use, and loss of water to maintain physiological homeostasis. Water in plants is not only the medium of nutrition but also, among other things, the agent of photosynthesis and cellular turgor pressure. Plants must control their water status, from leaf hydration to root development, to be healthy and grow.

Understanding how plants manage water relations is very useful for optimizing agricultural practices aimed at managing and improving crop production and health. These relations are studied to practically apply this knowledge toward efficient use of water, alleviation from drought stress, and sustainable agriculture and botanical applications.

Basic Concepts In Plant Water Relations

Terms related to water relations are described below.

Water Potential

It is defined as the potential energy of water in any system. The driving energy for the movement of water is gained from the water potential. This again gets divided into three main components. They are:

• Osmotic Potential: It is the potential of water to enter a solution that arises due to the solutes dissolved in it. Sometimes it is also referred to as solute potential.

• Pressure Potential: This is the real pressure which the fluid exerts and contributes to the turgor pressure of the plant cells.

• Matric Potential: It refers to the cohesion of water molecules to surfaces present in a plant's tissues and, as such, it influences the movement of water throughout the plant and in the soil.

Osmosis

Passive transport of water across a semipermeable membrane from low to high solute concentrations, equalizing the concentration of solutes.

Imbibition

This is the first absorption of water either by dry seed or any plant tissues that causes them to swell and triggers off activation of physiological activity.

Plasmolysis

When a plant cell loses water to a hypertonic solution, the cell membrane pulls away from the cell wall, reducing turgor pressure and possibly causing damage to the cell.