ABSTRACT
EFFECT OF SALT STRESS ON ANTIOXIDANT DEFENSE SYSTEMS OF
SENSITIVE AND RESISTANT CULTIVARS OF LENTIL
Cicerali, Iin Nur
M.Sc., Department of Biotechnology
Supervisor: Prof. Dr. Meral Yü / cel
Co-supervisor: Asst. Prof. Dr. Fü / sun (nci) Eyidoan
June 2004, 90 pages
In this study, two lentil cultivars (Lens culinaris, Medik.) (ILL5582-salt tolerant
and ILL590) were characterized and compared due to their NaCl susceptibility and
antioxidant mechanism was examined under laboratory conditions. Physiological
parameters such as wet-dry weight, root-shoot lengths, cell membrane stability, lipid
peroxidation in terms of malondialdehyde (MDA), H2O2, proline contents were
determined. The activities of antioxidant enzymes such as superoxide dismutase (SOD:
EC 1.15.1.1), catalase (CAT: EC 1.11.1.6), ascorbate peroxidase (APX: EC 1.11.1.11)
and glutathione reductase (GR: EC 1.6.4.2) were examined and analyzed in 14 days old
plant seedlings after 9 days of normal growth and 5 days of 100mM and 200mM NaCl
stress conditions.
Shoot-root length and wet-dry weight percent decrease were more in ILL590.
Especially shoot tissues were affected more from the stress conditions when compared
to root tissues.
ii
According to malondialdehyde (MDA) content and membrane stability results,
lipid peoxidation was higher in ILL590 and significant increases were observed in shoot
tissues.
Proline concentration showed a remarkable increase in salt concentration
dependent manner. Higher concentrations of proline in ILL5582 might be the reason of
higher salt tolerance when compared to ILL590.
Among the antioxidant enzymes SOD was the one which showed highest
activity increase. At organ level roots showed highest activity when compared to leaves.
In the organelle higher activity percent contribution was achieved by cytosolic
Cu/ZnSOD isozyme. Higher percent increase of this isozyme was observed in ILL5582.
This might be one of the tolerance mechanisms that get activated against NaCl stress.
APX activity showed similar alterations in both cultivars. In leaf tissues significant
increase was observed but in root tissues ascorbate peroxidase activity did not change
significantly. Glutathione Reductase activity increase was significant in both cultivars
leaf tissues but although ILL5582 showed a stress concentration dependent increase,
ILL590 did not. The activity of CAT enzyme in leaf and root tissues of both cultivars
did not significantly change under increasing salt stress conditions.
The results suggested that the leaves were more susceptible to salt stress.
Also when two cultivars were compared ILL5582 was found to be more tolerant against
salt stress than ILL590 under laboratory conditions and SOD enzyme seemed to be the
most active component of the salt tolerant mechanism.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/3/12605248/index.pdf |
| Date | 01 July 2004 |
| Creators | Cicerali, Isin Nur |
| Contributors | Yucel, Meral |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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