Mikail Akbulut

The effects of Se phytotoxicity on the antioxidant systems of leaf tissues in barley (Hordeum vulgare L.) seedlings.

A hydroponic experiment was carried out in a growth chamber to investigate the impact of Selenium (Se) levels on physiological and biochemical characteristics of a barley cultivar. Membrane lipid peroxidation (LPO), proline accumulation and antioxidant activities of some enzymes of barley seedlings under Se toxicity were investigated. Significant increase in thiobarbituric acid reactive substance (TBARS) content, and a stimulation of catalase (CAT, 1.11.1.6), ascorbate peroxidase (APX, 1.11.1.11), glutathione reductase (GR, 1.6.4.2), and glutathione S-transferase (GST, 2.5.1.18) activities were recorded in barley seedlings subjected to 2, 4, 8, 16 ppm Se. Superoxide dismutase (SOD, EC 1.15.1.1) activity was not altered significantly. Plant height and chlorophyll content of the seedlings were also affected significantly in a dose dependent manner by Se treatment. Considerable amount of proline accumulation was also observed in response to Se treatment. The results indicated that increases in the activities of the antioxidant enzymes were not sufficient to protect cell membrane against Se toxicity.

Chemical Composition and Fumigant Toxicity of Some Essential Oils Against Ephestia kuehniella

ABSTRACT The chemical constituents of some essential oils extracted from aromatic plants (savory, Satureja thymbra L.; Turkish oregano, Origanum onites L.; myrtle, Myrtus communis L.; marjoram, Origanum majorana L.; laurel, Laurus nobilis L.; lemon, Citrus limon L.; sticky goosefoot, Chenopodium botrysh L.; and tansy, Tanecetum armenum [DC] Suchultz Bip.) were analyzed by gas chromatographymass spectrometry. Fumigant toxicity of volatile compounds was tested against Mediterranean flour moth, Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae), eggs and adults. Percentage of mortality and longevity of E. kuehniella adults were estimated after essential oil treatments. LC50 and LC99 values were determined for each exposure time for each essential oil. Marjoram and lemon oils were the most effective of all the essential oils tested. The major components were linalool, 1.8-cineole, citral, 2-(4a.8-dimethyl-1.2.3.4.4a.5.6.7-octahydro-naphthalen-2-yl)-prop-2-en-l-ol, and p-cymene for marjoram, laurel, lemon, goosefoot, and tansy, respectively. The LC50 and LC99 values were estimated as 3.27 and 5.13 µl liter-1 air for marjoram and 4.05 and 5.57 µl liter-1 air for lemon essential oils at the longest exposure time. Decreasing longevity effect of marjoram and lemon was more prominent compared with other essential oils. We suggest that essential oils obtained from certain aromatic plants have potential as fumigants for stored product pests.

UPTAKE AND DISTRIBUTION OF SELENIUM, NITROGEN AND SULFUR IN THREE BARLEY CULTIVARS SUBJECTED TO SELENIUM APPLICATIONS

Selenium (Se) is an essential micronutrient for humans and animals, and also affects plant metabolism. In this study, the effects of increasing doses of Se application on the uptake of selenium (Se), nitrogen (N), and sulfur (S) content of three barley cultivars were investigated. The analysis indicated that the Se contents were highest in root tissues, intermediate in grain, and lowest in stem tissues in all cultivars. Total Se accumulations (whole plant) were highest in ‘Bülbül 89’ (0.171 mg kg−1), intermediate in ‘Çetin 2000’ (0.153 mg kg−1), and lowest in ‘Tarm 92’ cultivars (0.124 mg kg−1). In all cultivars, the increase in grain Se content resulted in a decrease in the grain N content. While ‘Bülbül 89’ can be suggested for biofortification purposes, less Se accumulating ‘Tarm 92’ cultivar can be suggested as a fodder in Se contaminated or high Se containing areas.

Native entomopathogenic nematodes isolated from Turkey and their effectiveness on pine processionary moth, Thaumetopoea wilkinsoni Tams

Two native entomopathogenic nematodes were isolated from soil samples in Eastern Mediterranean region of Turkey and characterized based on 28S rDNA region. BLASTN homology and phylogenetic analysis of SK17 and SK-71 isolates indicated 98% and 99% identity to Steinernema affine and Steinernema feltiae, respectively. The results were constructed by neighbour-joining and bootstrap tree methods. Efficacy of S. affine (SK-17 strain) and S. feltiae (SK-71 strain) was tested against the larvae of pine processionary moth, Thaumetopoea wilkinsoni Tams, and remarkable mortality rates were obtained. Both strains caused complete mortality upon application of 500 IJs in foliar tests. However, the same strains caused 30% and 33% mortality at 80 IJs/cm2 in soil applications. It was concluded that these native strains could be considered as potential biocontrol agents for reducing the damage caused by T. wilkinsoni larvae.

New combination in Veronica (Scrophulariaceae s.l.) based on morphological characters and the seed storage protein polymorphism

Veronica erciyasdagi (M. A. Fischer) C. Vural comb. & stat. nov., previously regarded as a variety, is proposed as a new combination, based on the morphological characters and seed storage protein polymorphism presented in this study. In addition, information about the ecology and conservation status of Veronica erciyasdagi was reported. This taxon is endemic to central Anatolia, Turkey and is critically endangered.

Grain amino acid composition of barley (Hordeum vulgare L.) cultivars subjected to selenium doses

Abstract Background: Selenium (Se34) is an essential micronutrient for humans and animals and has growth promoting and antioxidative effects at low concentrations. Methods: Effects of various sodium selenite (Na2SeO3) doses on grain amino acid content of barley cultivars (Bülbül 89 and Çetin 2000) was investigated using ion exchange liquid chromatography. Results: Majority of the amino acids could be altered with Selenium (Se) fertilization. Grain Se content of Bülbül 89 (0.175 mg kg−1) and Çetin 2000 (0.171 mg kg−1) were similar and both displayed an increase in proteinogenic, essential, and sulfur amino acids. The response of cultivars was more pronounced for Se accumulation and amino acid content at mid dose (12.5 mg ha−1). The quantities of proteinogenic, essential and sulfur amino acids increased considerably at that dose. Se induced increase in nitrogen content might cause an increase in some of the proteins of grain and consequently can alter amino acid composition. An obvious increase in the limiting amino acids (lysine and threonine) were prominent in response to Se fertilization. Conclusion: Se treatment influence amino acid composition of barley grains; especially improve the quantity of limiting amino acids and consequently nutritional value of the grain.