Category: Biology

Nitrogen fixation  The process of conversion of free nitrogen of the atmosphere into utilisable compounds of nitrogen such as nitrate, ammonia, amino acids etc is termed as nitrogen fixation.  …

Mechanism of biological nitrogen fixation The mechanism of biological nitrogen fixation follows different pathways for free living or asymbiotic and symbiotic systems.  However in both the systems, the molecular …

Active mineral salt absorption The absorption of ions, involving use of metabolic energy is termed as active salt absorption.  Energy used in this mechanism comes from metabolic activities, especially …

Mineral salt absorption Plants absorb mineral salts from the soil through the roots.  The zones of elongation and the root hairs are responsible for the mineral salt absorption.  They …

Guttation The process of exudation of liquid droplets from the margin and apex of the leaves of herbaceous plants is termed as guttation.   It was first studied by Bergerstein …

Factors affecting the rate of transpiration Many environmental factors, such as intensity of light, temperature, atmospheric humidity, wind, availability of soil water, etc., greatly affect the rate of transpiration.  …

Water potential:  Water potential is the difference between free energy of water in a system and the free energy of pure water at atmospheric pressure and a defined temperature.  It …

Availability of Soil water: The source of soil water is rain. Soil is the main reservoir of water for plants. The amount of water in soil is variable, which depends …

Pathways of water movements in roots: Apoplast and Symplast pathways Water from the soil comes into the plant mostly through root hairs in the piliferous layer of the root.  …

 Active absorption of water  When the water is absorbed due to the activity of root itself, particularly root hairs, it is called active absorption. Active absorption of water may …