Plant physiology is a specialized branch of botany that delves into understanding the functional mechanisms of plants. Interconnected with plant ecology, molecular biology, cell biology, morphology, and phytochemistry, it scrutinizes the internal dynamics of plants encompassing both chemical and physical phenomena. Central to its inquiries are pivotal processes like photosynthesis, respiration, tropisms, and hormonal regulation. Additionally, it explores phenomena such as seed germination, photoperiodism, photomorphogenesis, stress responses, transpiration, and circadian rhythms. Moreover, within its scope lies the study of plant nutrition, investigating the array of essential nutrients vital for plant growth and metabolism. This book is a valuable compilation of topics, ranging from the basic to the most complex concepts and theories related to the field of plant physiology. Coherent flow of topics, student-friendly language and extensive use of examples make this text an invaluable source of knowledge. It is an essential guide for both academicians and those who wish to pursue this discipline further.