Student:	FUAT YETİŞSİN
Supervisor:	DOÇ. DR. RABİYE TERZİ
Department:	Biyoloji
Institution:	Graduate School of Natural and Applied Sciences
University:	Karadeniz Technical University Turkey

Title of the Thesis:	INVESTIGATION ON THE PHOTOSYNTHETIC EFFICIENCY EFFECTS OF GLUTATHIONE, HYDROGEN PEROXIDE AND SALICYLIC ACID APPLICATIONS ON SENSİTİVE AND RESİSTANT MAIZE VARIETIES EXPOSED TO COPPER STRESS
Level:	Ph.D.
Acceptance Date:	10/6/2015
Number of Pages:	142
Registration Number:	Di1081

Summary:

In this study, alleviating effects of glutathione (GSH), hydrogen peroxide (H2O2) and

salicylic acid (SA) pre-treatments on antioxidant system enzymes, the expression of some

genes and photosynthetic system of copper stressed maize varieties, 31G98 (resistant to

copper) and Akpinar (sensitive to copper) were studied. Effects of these treatments on water

content, stomatal conductance, membrane damage, photosynthetic pigment contents,

endogenous copper, H2O2, GSH and SA levels, dry weight, growth inhibition, proline amount,

polyamine content, ABA content, photosynthetic rate, transpiration, chlorophyll fluorescence,

rubisco activity and concentration were examined via spectrophotometry and Western blot

methods. In addition, the enzyme activities of superoxide dismutase, catalase, ascorbate

peroxidase, glutathione reductase and guaikol peroxidase and the expression of abscisic

aldehyde oxidase (AAOX), glutathione synthetase (GSHSY) and NADPH oxidase (NOX) genes

were investigated. Copper stress was found to increase endogenous GSH, H2O2, SA, ABA,

poliamine, proline, MDA, antioxidant enzyme system and NOX, GSHSY, AAOX gene

expression. On the other hand, the stress was decrease the rubisco concentration,

photosynthetic activity, transpiration, water potential and dry weight. GSH, H2O2 and SA

application was found to mitigate negative effects of the stress by induced antioxidant system

at different rates in both maize varieties. It was concluded that pretreatments of 0,05 mM

GSH, 10 mM H2O2 and 0,01 mM SA had alleviating effects on maize cultivars under copper

stress.

Key Words: Copper Stress, Chlorophyll Fluorescence, Glutathione, Hydrogen Peroxide,

Maize, photosynthetic efficiency, Salicylic Acid