Glutathione reductase (GR) and superoxide dismutase (SOD) enzymes are
thought to play an important role in the plant chloroplast antioxidant system.
Tobacco plants transformed with E. coli glutathione reductase and superoxide
dismutase genes were used to investigate the role of these gene products
(enzymes) in the chloroplast antioxidant system. These plants were T1318
(transformants with increased levels of cytoplasmic glutathione reductase activity)
and GOR1OT (transformants with increased levels of cytoplasmic' glutathione
reductase activity and chloroplastic superoxide dismutase).
In addition, 10~M methyl violegen (paraquat), was used to perturb the system
experimentally under high light, low light and in darkness. During these
experiments GRA (glutathione reductase activity) was assayed and the results
expressed as mg-1protein, mg-1 chlorophyll and g-1 tissue, using different types
of transgenic plants.
T131 B-cytosolic GOR transformants had a higher GRA under high light intensity.
Under low light intensity T131B had a small increase in GRA compared to
controls (T131 Bs in 1mM CaS04). Also leaf discs in the dark showed similar
GRA as did controls. The three treatments had no effect on the GRA of
untransformed plants. GOR1OT (cytoplamic GOR and chloroplastic SOD
transformants) had a slight increase in GRA under high light intensity and in
darkness. At low light intensity GOR10T showed similar results to controls.
The results indicate the overall absolute increase in GRA in transgenic plants
after methyl violegen treatment. The higher activity than that of nontransgenic
controls indicate that bacterial GRA must have also increased following exposure
to methyl violegen. / Thesis (M.Sc.)-University of Natal, 1996.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/4979 |
| Date | January 1996 |
| Creators | Dlamini, Zodwa Lawrentia. |
| Contributors | Amory, Alan M. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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