Occurrence, Biosynthesis and Potentialities of Ascorbic Acid in Plants

Ascorbic acid (AA) is found in all eukaryotes including animals and plants and lacks completely in prokaryotes except cyanobacteria, have been reported to have a small amount of AA. It is an antioxidant and, in association with other components of the antioxidant system, protects plants from oxidative damage resulting from aerobic metabolism, photosynthesis and a range of pollutants like ozone, heavy metal and saline stress. In addition, it is not only an antioxidant; it also appears as a co-factor for several metabolic enzymes involved in the fundamental developmental process of plants and a well known cellular reductant with an intimate and comprehensive role in the response to environmental stress. Also, some studies suggests that the endogenous AA has been implicated in the promotion of plant growth and development by involving in a complex array of phytohormone-mediated signaling network that ties together different environment stress. Indeed, in addition to acting simply as an antioxidant and cellular reductant, AA influences transition from the vegetative to the reproductive phase and the final stage of development, senescence. Since the biosynthetic pathway of AA in plants has not been identified and evidence for the proposed pathway is reviewed slightly in this review. Therefore, there are a need to increase our understanding of this enigmatic molecule since, it could be involved in a wide range of developmental phenomenon’s as well as works against actual stress in order to regulate better growth and development.