The effect of orobanchec cumana Wallr. on superoxide dismutase (SOD;EC.1.15.1.1) and peroxidase (POD;EC.1.11.1.7) activities in some sunflower varieties

THE EFFECT OF Orobanche cumana Wallr. ON SUPEROXIDEDISMUTASE (SOD;E.C.1.15.1.1) AND PEROXIDASE (POD;E.C.1.11.1.7)ACTIVITIES IN SOME SUNFLOWER VARIETIESABSTRACTOrobanche cumana Wallr. is a holoparasitic angiosperm which infectsHelianthus annuus L. roots. It originated in the Mediterranean regio. O. cumanaWallr. seeds were collected on infested sunflower fields in Thracia region(Hayrabolu-Tekirdağ). In this research some O. cumana resistant sunflower varieties(PIONEER 4223 and SANAY) and sensitive one (ISERA) were used.O.cumana Wallr. seeds were placed in petri dishes and were kept there for oneweek and then GR 24 was applied. After GR 24 treatment sunflower seedlings weregrown in hydroponic culture for one week before infestation, and germinatingbroomrape seeds were penetrated into sunflower roots. After the penetration,sunflower roots were harvested to determine the total protein and anthioxidantenzyme activities in first, third, fifth, seventh and ninth days respectively. Theinteraction of O. cumana Wallr. with resistant and sensitive sunflower varieties(ISERA, SANAY, PIONEER 4223) in Turkey was investigated and the changes inSuperoxide dismutase (SOD;E.C.1.15.1.1) and Peroxidase (POD;E.C.1.11.1.7)activities were identified.The results indicate that ISERA, which is known as a sensitive variety to O.cumana Wallr., contains high total SOD amount in antioxidative responses in shorttime. But these results are not supported with peroxidase activity. PIONEER 4223,which is known as a resistant variety to O. cumana Wallr., displays antioxidativeresponses to functional expressive increase in both total SOD amount and POXactivity. These results indicate that total SOD amount and POX activity of ISERAare not compatible. It may explain sensitive mechanism of ISERA. SANAY isknown as a resistant variety with using total herbicide. In this research, this chemicalvisubstance was not examined. The total amount of SOD in SANAY variety isobscure. When SANAY is compared with ISERA, higher level of peroxidaseactivity were determined in same application group than that of control group inSANAY.However, no significant increases were identified for two antioxidativeenzymes in application group in comparison with control group. This result indicatesthat SANAY and ISERA varieties are sensitive to O. cumana Wallr. in the sameway.In our experiment, it was determined that PIONEER 4223 variety constituted aperfect response especially for a short time to oxidative stress appearing as a resultof the interaction sunflower with Orobanche.Key words: Sunflower, Helianthus annuus, ISERA, PIONEER 4223, SANAY,Orobanche cumana, Superoxide dismutase, SOD, Peroxidase, POD, Oxidativestress, Antioxidant enzymes.The present M.Sc. thesis was supported by Çanakkale Onsekiz Mart UniversityBAP under the project no of 2005/27.vii