Ascorbic Acid-A Potential Oxidant Scavenger and Its Role in Plant Development and Abiotic Stress Tolerance

Abstract

Over-production of reactive oxygen species (ROS) in plants under stress conditions is a common phenomenon. Plants tend to counter this problem through their ability to synthesize ROS neutralizing substances including non-enzymatic and enzymatic antioxidants. In this context, ascorbic acid (AsA) is one of the universal non-enzymatic antioxidants having substantial potential of not only scavenging ROS, but also modulating a number of fundamental functions in plants both under stress and non-stress conditions. In the present review, the role of AsA, its biosynthesis, and cross-talk with different hormones have been discussed comprehensively. Furthermore, the possible involvement of AsA-hormone crosstalk in the regulation of several key physiological and biochemical processes like seed germination, photosynthesis, floral induction, fruit expansion, ROS regulation and senescence has also been described. A simplified and schematic AsA biosynthetic pathway has been drawn, which reflects key intermediates involved therein. This could pave the way for future research to elucidate the modulation of plant AsA biosynthesis and subsequent responses to environmental stresses. Apart from discussing the role of different ascorbate peroxidase isoforms, the comparative role of two key enzymes, ascorbate peroxidase (APX) and ascorbate oxidase (AO) involved in AsA metabolism in plant cell apoplast is also discussed particularly focusing on oxidative stress perception and amplification. Limited progress has been made so far in terms of developing transgenics which could over-produce AsA. The prospects of generation of transgenics overexpressing AsA related genes and exogenous application of AsA have been discussed at length in the review.

Diverse salinity responses in Crithmum maritimum tissues at different salinities over time

“…Plants have evolved both non-enzymatic and enzymatic antioxidative defence mechanisms in order to mitigate the effects of increased ROS during salinity stress. Ascorbic acid is a primary substrate in the cyclic enzymatic pathway that detoxifies hydrogen peroxide (Akram et al, 2017). The enzymatic defence system consists of a battery of enzymes that interconvert ROS moieties into the less damaging H 2 O 2 , and then remove it.…”

A metabolomics study of ascorbic acid‐induced in situ freezing tolerance in spinach (Spinacia oleracea L.)

“…The effect of AsA on plant growth as well as stress tolerance is dependent upon the mode of application and concentration (Akram et al, ). Hence, we first tested four AsA concentrations (i.e., 0.5, 1.0, 2.0, and 4.0 mM) as sub‐fertigation treatments.…”

“…The effect of AsA on plant growth as well as stress tolerance is dependent upon the mode of application and concentration (Akram et al, 2017). Hence, we first tested four AsA concentrations (i.e., 0.5, 1.0, 2.0, Research shows that exogenous application of AsA improved plant growth in wheat (Athar, Khan, & Ashraf, 2008) and millet (Hussein & Alva, 2014).…”

Ascorbic acid improves the tolerance of wheat plants to lead toxicity

“…ASC regulates a number of cellular processes, such as cell division, cell differentiation and senescence (Venkatesh and Park 2014). Furthermore, ASC protects lipids and proteins and improves tolerance against various abiotic stresses, induces plant growth, photosynthesis, transpiration, oxidative defense potential and photosynthetic pigments (Khan et al, 2010;Naz et al, 2016, Akram et al, 2017. However, none or meager information is available on ASC mediated S-and N-assimilation pathway involved in detoxification of Pb in plants.…”