The sub-field of botany that deals with the study of the functioning of plants is referred to as plant physiology. It is closely related to the fields of plant morphology, plant ecology, cell biology, molecular biology and phytochemistry. It focuses on the internal activities of plants including the chemical and physical processes. It also studies the fundamental processes such as photosynthesis, respiration, plant hormone function and tropisms. It also deals with photoperiodism, photomorphogenesis, seed germination, environmental stress philosophy, circadian rhythms and transpiration. Plant nutrition, which studies the different nutrients that are essential for the growth and metabolism of plants, also falls under the umbrella of this field. This book provides comprehensive insights into the field of plant physiology. Some of the diverse topics covered herein address the varied branches that fall under this category. This book will serve as a valuable source of reference for those interested in this field.