Abiotic stress factors frequently constrain the growth and productivity of major crop species. The single greatest abiotic stress factor that limits crop growth worldwide is water availability. While genetic increases in yield potential are best expressed in optimum environments, they are also associated with enhanced yields under drought and nitrogen deficiency. These gains are especially relevant given that further large increases in the area under irrigation are not expected, and land deterioration associated with intensive agriculture threatens those areas already irrigated. This book is intended to cover all known factors of abiotic stresses and their respective effects on some of the important aspects of physiological processes in plants.