Impact of Hydrogen Peroxide on the Secondary Metabolites, Enzyme Activities and Photosynthetic Pigment Accumulation of Vigna unguiculata L. (Walp)

Ezekiel Dare Olowolaju

doi:10.15835/nsb11310420

Abstract

The effects of exogenous application of hydrogen peroxide on the secondary metabolites, enzyme activities and photosynthetic pigment accumulation of Vigna unguiculata was investigated. The hereby study was carried out under a screen house to minimize extraneous factors. The experiment was laid down in completely randomized design (CRD) with eight replicates. After two weeks of sowing when the seedlings become fully established, the sample pots were divided into two regimes. The first regimes were supplied daily with 500 mL of 0.1 mM of hydrogen peroxide and the second regime was watered daily with tap water. After fifth week of sowing, the leaves of Vigna unguiculata from each regime were randomly selected and harvested. Secondary metabolites, enzyme assay and photosynthetic pigment screening was carried out on the harvested leaves. The impact of hydrogen peroxide on the parameters studied was done using one way analysis of variance. Mean values were separated using Fisher’s LSD at p≤0.05. The results showed that hydrogen peroxide strongly increased the accumulation of secondary metabolites such as flavonoids, glycosides, saponins, carbohydrates and alkaloids. It also induced α-amylase and lipase activities than the control plants and promotes the accumulation and biosynthesis of chlorophylls and carotenoids. In conclusion, hydrogen peroxide could be used as potential molecule to improve some secondary metabolites (flavonoids, glycosides, saponins, carbohydrates and alkaloids), α-amylase and lipase activities and photosynthetic pigments.

Highlights

Hydrogen peroxide (H2O2) and other reacting oxygen species such as the superoxide anion radical (O2ˉ), hydroxyl radical (HO), perhydroxyl radical (HO2ˉ), and singlet oxygen (1O2ˉ) (Bartosz, 1997; Dat et al, 2000; Halliwell, 2006) generally, are fundamental fact of life in an aerobic environment (Moller, 2001)
The aim of this study was to evaluate the effects of hydrogen peroxide on the on the secondary metabolites, enzyme activities and photosynthetic pigment accumulation of Vigna unguiculata
One unit of enzyme activity is defined as the amount of enzyme that will release 1 μmol of glucose of reducing sugar in 1 minute under assay conditions

Summary

Introduction

Hydrogen peroxide (H2O2) and other reacting oxygen species such as the superoxide anion radical (O2ˉ), hydroxyl radical (HO), perhydroxyl radical (HO2ˉ), and singlet oxygen (1O2ˉ) (Bartosz, 1997; Dat et al, 2000; Halliwell, 2006) generally, are fundamental fact of life in an aerobic environment (Moller, 2001). Hydrogen peroxide being the most stable reacting oxygen species, it is an important cellular component with various functions in the development, metabolism and homeostasis of aerobic organisms (Bienert et al, 2006) and regulate basic internal and external physiological processes such as photosynthesis, respiration, cell elongation and division (Barba-Espin et al, 2010). In plants H2O2 is generated via superoxide, presumably in a non-controlled manner, during electron transport processes such as photosynthesis and mitochondrial respiration (Neill et al, 2002). Hydrogen peroxide (H2O2) is a strong and viable oxidant that long has been applied in agriculture, industries and water treatment processes

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