DEMIRAL, Tijen Harran Üniversitesi - Fen - Edebiyat Fakültesi - Biyoloji Bölümü, Turkey , HAMURCU, Mehmet Selçuk Üniversitesi - Ziraat Fakültesi - Toprak Bilimi ve Bitki Besleme Bölümü, Turkey , HAKKI, Erdoğan E. Selçuk Üniversitesi - Ziraat Fakültesi - Tarla Bitkileri Bölümü, Turkey , GEZGIN, Sait Selçuk Üniversitesi - Ziraat Fakültesi - Toprak Bilimi ve Bitki Besleme Bölümü, Turkey

Effect of Boron Toxicity on Antioxidant Enzyme Activities of Durum Wheat (Triticum durum) Varieties

31183

Plants have developed several enzymatic and non-enzymatic antioxidant mechanisms to control physiological production of reactive oxygen species. Two durum wheat varieties (Kiziltan-91 and Çakmak-79) tolerance of which against boron stress had previously been determined were exposed to various concentrations of boron (0, 25, 250 ve 500 mg B kg^-1) to determine the differences in antioxidative enzyme levels. Resistance against boron stress partly depends on the enhancement in antioxidative system involving antioxidative compounds and several antioxidant enzymes. SOD is an antioxidant enzyme playing a key role by scavenging superoxide radicals in aerobic organisms. Activities of SOD isozymes were increased by increased toxicity of boron and Cu/Zn SOD exhibiting the most prominent isozyme band. Isozyme bands occurred in Kızıltan-91 were denser than those in Çakmak-79 compared to control group. CAT is one of the most effective antioxidant enzymes involved in preventing cellular damage and scavenge a strong oxidizing radical in peroxisomes H2O2 into H2O and molecular oxygen. CAT activity of both wheat varieties increased by increasing concentrations of boron on day 7 and this increase was higher in Kızıltan-91 than Çakmak-79. However, CAT activity of Kızıltan- 91 was decreased by exposure to 500 mg B kg^-1. POX activities of both varieties showed enhancement by increased concentrations of boron in our study.

532

Durum wheat , boron toxicity , CAT , POX , SOD

The Journal Of Ege University Faculty Of Agriculture

535