“Stress”, according to the dictionary, is “pressure or tension exerted on an object”. In the treatise that is in your hands, the author has made an unstinted effort to tell you on what and how does “Plant” (meaning “rice”) as an object express in submergence. Plant stress, frequently abiotic in nature, triggers a wide variety of plant responses, right from altered gene expression and biochemical metabolism to changes in growth rates, as well as crop yields. Among the abiotic stresses, submergence stress is one of the most adverse factors determining the growth and productivity of rice crops in Barak and Brahmaputra valleys and other hilly terrains of India. This treatise has evaluated both the physiology and bio-chemistry of submergence tolerance as well as intolerance of rice cultivars with different root responses. The author hopes that the treatise would be precious to those who intend to carry out or, for that matter, do research in the subject.