Plant Physiology 2011. Macronutrients Nitrogen Source: The chief source is the soil. Plants absorbs it either in the form of nitrate or ammoniacal salts.
Diseases (causative agents) (1) Biotic Diseases Causative organisms: Virus, Bacteria, Fungi, Actinomycetes, Nematodes (2) Abiotic Diseases (I) Physiological.
