Nitric Oxide

Abstract

Several studies indicate that nitric oxide (NO) is an endogenous signal in plants that mediate responses to several environmental stresses. NO was found to play a crucial role in plant growth and development, germination, flowering, ripening of fruit, and senescence of organs. Evidence of the influence of NO in many of the plant responses to external conditions and/or its physiological state has been obtained by the application of exogenous NO, usually in the form of NO donors or gas fumigation. However, in case of environmental stress, caused by both abiotic and biotic factors,enhanced endogenous NO generation is observed in different plant species and organs. This chapter is mainly focused on the role of NO in plant metabolism, its effects on postharvest quality, and shelf life. The hypothesis that NO generation occurs as a general response to different environmental stress is generally accepted and many examples are presented. The physiological significance of NO application is discussed. Recent reports provide an exceptional picture of NO production, regulation, and itsbioactivity in the plants, in particular during the latest stages of development of the plant. Furthermore, other promising studies of NO role in germination, growth, and development are presented to know the crucial role of NO during the entire life cycle of the plant.