Crop physiology is concerned with the processes and functions of the crops at cellular, sub-cellular and whole plant levels in response to environmental variables and growth. In short, physiology is the study of functional aspects of crop plants. This book is published for the purpose of competitive examination preparation like JRF, SRF, M.Sc. and Ph.D. Entrance and ICAR examination.This Book contains four chapters starting from cell organelles, soil water relations, Photosynthesis, Respiration, Plant mineral nutrition and Plant Growth Regulators.