Browsing by Author "Ozlem, Uzal"

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The Effects of Ja Treatment on the Growth and Some Enzyme Activities of Eggplant Embryos Grown in Vitro Under Salt Stress Conditions
(Research Journal Biotechnology, 2013) Manar, Talhouni; Banu, Gunalp; Fikret, Yasar; Sebnem, Kusvuran; Ozlem, Uzal; Sebnem, Ellialtioglu
In many areas of the world, soil salinization is an important concern for the sustainability of irrigated agriculture and accounts for large decreases in the yield of a wide variety of crops. Numerous attempts have been employed to optimize plant growth under saline conditions. One of them is to produce salt tolerant genotypes in different crops by traditional breeding. In addition, many other attempts have been made to overcome this disorder by exogenous application of plant growth regulators. Plant hormones are active members of the signal compounds involved in the induction of plant stress responses. Jasmonic acid (JA), which is naturally synthesized by plants, plays an important role as a signal molecule that induces the tolerance mechanisms under the influence of both biotic and abiotic stresses. In this study we aimed to investigate the effects of JA individually and/or accompanied with salt stress on two cultivars of eggplant embryos cultured in vitro. Embryos gently isolated from the 32-days old eggplant seeds and then were transplanted onto hormone-free MS medium basically containing 2% saccharose, 0.7% agar at pH 5.7. Different concentrations of NaCl and JA were applied with nine different applications. Two cultivars of eggplant were used: cv. Mardin Kiziltepe (M: Tolerant) and cv. Kemer (K: Sensitive). Germination percentage and antioxidative enzymes, SOD, CAT and APX activities were determined after harvesting. Among all applications of JA, plantlets that were pre-treated with 10 mu M JA and then transferred to the salty media showed relatively better development than the other applications. Germination rate was 100% and plant growth was normal in control application. However germination rate and plant growth were inhibited by salt or JA application. The addition of JA caused more inhibition than salt stress. Among all applications of JA, embryos that were pre-treated with JA (cultured on the medium with 10 mu M JA for 4 days and then transferred to the growth media with salt) showed relatively better development than the others. Antioxidative enzyme (SOD, CAT and APX) activities, increased with salt or JA treatments compared to control plants. The SOD, CAT and APX activities of the salt-tolerant Mardin Kiziltepe genotype were higher than salt-sensitive Kemer variety.
Sod, Cat, Gr and Apx Enzyme Activities in Callus Tissues of Susceptible and Tolerant Eggplant Varieties Under Salt Stress
(Research Journal Biotechnology, 2013) Fikret, Yasar; Manar, Talhouni; Sebnem, Ellialtioglu; Sebnem, Kusvuran; Ozlem, Uzal
When plants are subjected to environmental stresses such as temperature extremes, drought, salinity or heavy metal toxicity, they produce reactive oxygen species ROS causing oxidative damage. Plants with high levels of antioxidants, either constitutive or induced, have been reported to have greater resistance to the oxidative damage. In our previous studies, we examined the relationship between antioxidant enzymes and salt tolerance in the leaves of the eggplant seedlings of two salt-tolerant genotypes (Burdur Bucak-BB and Mardin Kiziltepe-MK) and two salt-sensitive genotypes (Giresun-GI and Artvin Hopa-AH) and we found that the salt-tolerant varieties contained significantly higher constitutive levels of catalase and induced levels of SOD, APX and GR. SOD, CAT, GR and APX enzyme activities were determined in callus tissues. Under salt stress at the 8th day, significant differences were found in the aspect of SOD activity between salt-tolerant and salt-sensitive eggplant varieties. Concerning CAT, GR and APX activities, it is found that the 4th day calculations were significant and gave a high correlation with the tolerance levels of genotypes. The data indicated a strong correlation between antioxidant enzyme activity and the ability of eggplant callus tissue to grow on media amended with NaCl. The salt-induced increase in antioxidant enzyme activities in callus tissue was found at the highest level in salt tolerant eggplant varieties. The genotypical differences in salt tolerance observed at whole plant level experiments were also apparent in callus cultures of eggplant. These results show that callus cultures can be useful for the screening programs to determine the salt tolerance level in eggplant.