Please read the attached publication

Esam H. Mansour

Article Overexpression of Superoxide Dismutase Protects Plants from ...

Article The combination of metallothionein and superoxide dismutase ...

Article A novel form of the human manganese superoxide dismutase pro...

Try C.N. Giannapolitis, S.K. Ries, Superoxide dismutase. I. Occurrence

in higher plants, Plant Physiol. 59 (1977) 309–314.

Please refer to the paper attached for 'SOD' activity measurement:

"A microtiter plate assay for superoxide dismutase using a water-soluble tetrazolium salt (WST-1)"

Alexander V Peskin, Christine C Winterbourn

Clinica Chimica Acta

Volume 293, Issues 1–2, March 2000, Pages 157–166

http://www.sciencedirect.com/science/article/pii/S0009898199002466

You may follow protocol in  -

Schoner, S., Krause, G.H., 1990. Protective system against active oxygen species in spinach: responses to cold acclimation in excess light. Planta 180, 383–389.

or attached paper

Commercial kit is also available such as:

Superoxide Dismutase Activity Colorimetric Assay Kit (ab65354), from Abcom company. [http://www.abcam.com/superoxide-dismutase-activity-colorimetric-assay-kit-ab65354.html ]

Product description:

Abcam's Superoxide Dismutase Activity Colorimetric Assay Kit is a sensitive kit using WST-1 that produces a water-soluble formazan dye upon reduction with superoxide anion. The rate of the reduction with a superoxide anion is linearly related to the xanthine oxidase (XO) activity, and is inhibited by SOD. Therefore, the inhibition activity of SOD can be determined by a colorimetric method.

Go to their website (at FAQ) for (possible free to use their product):

They don't offer test samples, but they said: "assay kits are included on Abcam's AbTrial program, where you can use our products in an untested application or species without the financial risk".

Thank you very much to all of you

Commercial kits are good and available from different companies such asRandox,Abcom.see also spectrophotometeric assays for antioxidant enzymes in plant stress tolerance  method and protocols bySathy Elavarth andJorn Martin edts 2010