Fresh plant material (1g) was homogenized in 100 mM Tris-HCl (pH 7.5) in presence of DTT (Dithiothreitol, 5 mM), MgCl2 10 mM, Ethylenediaminetetraacetic acid (EDTA, 1 mM), magnesium acetate 5 mM, Polyvinylpyrolidone (PVP-40 1.5%), phenylmethanesulfonyl fluoride (PMSF 1 mM) and aproptinin 1 μgmL-1. After the filtration, the homogenate was centrifuged at 10,000 rpm for 15 min. The supernatant collected after centrifugation served as enzyme source. For the analysis of APX activity, tissues were separately homogenized with 2 mM AsA. All experiments were performed at 4°C.
Activity of SOD was estimated according to Kono (1978) (link) following the photo reduction of nitroblue tetrazolium (NBT). The absorbance was recorded spectrophotometerically (Beckman 640 D, USA) at 540 nm. SOD unit is the quantity of enzyme that hamper 50% photoreduction of NBT and is expressed as EU mg-1 protein.
The activity of POD was estimated according to the method proposed by Putter and Becker (1974) . The rate of production of oxidized guaiacol was estimated spectrophotometerically (Beckman 640 D, USA) at 436 nm. The activity of POD was expressed as EU mg-1 protein.
Catalase activity was estimated by the method of Aebi (1984) (link). The OD was taken spectrophotometerically (Beckman 640 D, USA) at 240 nm and the activity was expressed as EU mg-1 protein.
For the determination of APX activity, the procedure of Nakano and Asada (1981) was used. The OD was recorded at 265 nm by spectrophotometer (Beckman 640 D, USA) and the activity was expressed as EU mg-l protein.
Activity of SOD was estimated according to Kono (1978) (link) following the photo reduction of nitroblue tetrazolium (NBT). The absorbance was recorded spectrophotometerically (Beckman 640 D, USA) at 540 nm. SOD unit is the quantity of enzyme that hamper 50% photoreduction of NBT and is expressed as EU mg-1 protein.
The activity of POD was estimated according to the method proposed by Putter and Becker (1974) . The rate of production of oxidized guaiacol was estimated spectrophotometerically (Beckman 640 D, USA) at 436 nm. The activity of POD was expressed as EU mg-1 protein.
Catalase activity was estimated by the method of Aebi (1984) (link). The OD was taken spectrophotometerically (Beckman 640 D, USA) at 240 nm and the activity was expressed as EU mg-1 protein.
For the determination of APX activity, the procedure of Nakano and Asada (1981) was used. The OD was recorded at 265 nm by spectrophotometer (Beckman 640 D, USA) and the activity was expressed as EU mg-l protein.
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