Influence of ionizing irradiation on the antioxidant enzymes of &lt;i&gt;Vicia faba&lt;/i&gt; L.

Amina A Aly,Hossam E S El-Beltagi

doi:10.3989/gya.111509

Abstract

The seeds of Vicia faba L. Giza 834 were exposed to γ-irradiation at dose levels of 2.5, 5.0, 10.0 and 20.0 kGy and after that exposed to He–Ne (632.8 nm) or diode (650.0 nm) laser irradiation for 5 min. The activities of POD, APOX, CAT, SOD and GST enzymes were significantly stimulated and this stimulation reached its maximum at a dose level of 5.0 kGy for enzymes POD, APOX, CAT and SOD, but for GST enzyme at a dose level 10.0 kGy. For He- Ne laser, with or without different doses (2.5, 5.0, 10.0 and 20.0 kGy) of γ-irradiation, enzyme induction was significantly stimulated and positively correlated with the dose levels of γ-irradiation in combination with the He-Ne treatment. There was a significant increase in the concentration of MDA and this increase was more pronounced at dose level 20.0 kGy (38.2 μmol/g d.w) compared to the control (3.9 μmol/g d.w). Laser treatment by He–Ne laser or diode laser only caused a slight increase (P 2 O 2 content significantly increased in all treatments and this increase reached its maximum at dose level 20.0 kGy (36.3 μmol/g d.w) compared to the control (2.3 μmol/g d.w.). On the other hand, He-Ne or diode laser treatments combined with γ-irradiation significantly decreased in comparison with γ-irradiation treatments alone. In the case of glutathione content, there were significant increases by γ-irradiation at dose levels 2.5, 5.0, 10.0 and 20.0 kGy. Furthermore, with a combination of γ-irradiation and He-Ne or diode laser, a marked increase in glutathione content was found and was more pronounced than that of gamma irradiation alone.

Highlights

Under natural conditions of growth and development, plants are inevitably exposed to different types of stress, which may cause an increased production of active oxygen species 1993)
Plants are well known to possess effective enzymatic and non-enzymatic detoxifying systems continually involved in the cellular protection against reactive oxygen species (ROS) coming from both the environment and cell metabolism
Vicia faba L. seeds to different sources of ionizing irradiation had different effects on antioxidant enzymes, peroxidase, ascorbate peroxidase, catalase, superoxide dismutase and glutathione-S-transferase as well as MDA, H2O2 and GSH contents as shown in (Tables 1-2)

Summary

Introduction

Under natural conditions of growth and development, plants are inevitably exposed to different types of stress, which may cause an increased production of active oxygen species 1993) These include superoxide (RraOdSic)a(lSs m(irOn2o.–f)f,, singlet oxygen (1O2), hydrogen peroxide (H2O2) and hydroxyl radicals (OH.), which cause tissue injury. ROS are highly reactive in the absence of any protective mechanism, they can seriously disrupt normal metabolism through oxidative damage to membrane lipids, proteins, pigments and nucleic acids. These ROS are detoxified by the sequential and INFLUENCE OF IONIZING IRRADIATION ON THE ANTIOXIDANT ENZYMES OF VICIA FABA L simultaneous action of a number of enzymes, including glutathione reductase (GR; EC 1.8.1.7) superoxide dismutase (SOD; EC 1.15.1.1), peroxidase

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