Yazar "Akiscan, Yasar" seçeneğine göre listele
Listeleniyor 1 - 5 / 5
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Antioxidant response to drought in red and white clover(Springer Heidelberg, 2012) Vaseva, Irina; Akiscan, Yasar; Simova-Stoilova, Lyudmila; Kostadinova, Anelia; Nenkova, Rosa; Anders, Iwona; Feller, UrsAntioxidant response to drought in red (Trifolium pratense L., cv. Start) and white clover (Trifolium repens L, cv. Haifa and cv. Debut) grown as soil cultures was evaluated in water-deprived and recovered plants. Drought provoked oxidative stress in leaves confirmed by the considerable changes in electrolyte leakage, malondialdehyde, hydrogen peroxides and proline contents. Immunoblot of Delta-1-pyrroline-5-carboxylate synthetase (P5CS), which catalyzes the first two steps in proline biosynthesis, revealed strong induction of the enzyme in red clover plants submitted to drought. Water-deprived white clover plants exhibited distinct P5CS profiles. This was related to different drought tolerance of the studied T. repens cultivars. Isoenzyme analyses of superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) demonstrated certain differences in antioxidant defence among the tested varieties. It was confirmed that MnSOD (in both T. repens and T pratense) and FeSOD (in T. repens) isoforms were the most affected by drought. The red clover cultivar Start exhibited the lowest FeSOD and POX activities which could contribute to its poor performance under water deprivation.Öğe Drought stress tolerance of red and white clover-comparative analysis of some chaperonins and dehydrins(Elsevier, 2011) Vaseva, Irina; Akiscan, Yasar; Demirevska, Klimentina; Anders, Iwona; Feller, UrsThe ecophysiological function linked to the contribution of the legume to the nitrogen supply of the sward, as well as its high content in pastures, make red (Trifolim protense) and white clover (Tnfolium repens) forage plants of economic importance in temperate regions. The study aimed to characterize the expression profiles of some important stress tolerance related proteins in red clover (cv. Start), and two white clover cultivars - cv. Haifa (medium-leafed) and cv. Debut (small-leafed). An attempt has been made to explain the differences in red and white clover potential to sustain unfavorable environmental conditions regarding the obtained results from protein and gene profiling. Rubisco binding protein (RBP), low molecular weight heat shock proteins (HSP), calpains (ClpA and ClpP) and dehydrins (DHN) responded significantly to drought. White clover cv. Debut developed the lowest leaf water deficit (WD) compared to the one detected in red clover and the medium leafed white clover cultivar Haifa. Immunoblot and RT-PCR showed that the small leafed white clover cv. Debut copes with drought stress most efficiently. Detailed gene expression analysis revealed that Y2SK type dehydrins were subjected to alternative splicing under drought and the transcripts were strongly induced in the more drought tolerant small-leafed white clover cultivar Debut. A homolog sequence of Y2K dehydrin in T. pro tense (GenBank ID: JF748409) and T. repens (GenBank ID: JF748410) have been amplified and an increased transcipt levels of JF748409 were detected in T. pratense drought stressed leaves. The expression pattern of SK2 transcripts showed that this dehydrin type has been down-regulated in both white clover cultivars under water deprivation. (C) 2011 Elsevier B.V. All rights reserved.Öğe Effect of different irrigation water level on cotton yield and yield components(Academic Journals, 2009) Onder, Derya; Akiscan, Yasar; Onder, Sermet; Mert, MehmetEffects of different water level on yield and yield components of the drip irrigated cotton were evaluated in Amik Plain in the East Mediterranean Region of Turkey. Four levels of irrigation water were tested in 2003 and 2004. Treatments were 25 (I-25), 50 (I-50), 75% (I-75) of the full irrigation treatment (I-100) which received 100% class-A pan evaporation. Numbers of irrigation events were 5 and 8 in 2003 and 2004, respectively. Under I-25, I-50 and I-75 treatment conditions, evapotranspiration, total cotton seed yield, boll weight, lint percentage, number of sympodial branches and leaf area index decreased while some boll parameters such as boll weights and opened boll numbers increased. Increase of boll number per plant under water stress condition showed that cotton had high ability for adapting water stress conditions. The highest yield was obtained in the I-100 treatment. A second degree polynomial relation could adequately describe the cotton seed yield response to the irrigation water amount. The highest irrigation water use efficiency (IWUE) was obtained with the I-50 treatment.Öğe Genetic diversity of Turkish commercial cotton varieties revealed by molecular markers and fiber quality traits(Tubitak Scientific & Technological Research Council Turkey, 2014) Elci, Eminur; Akiscan, Yasar; Akgol, BatuhanTo assess the genetic diversity and relationships among commercial Gossypium species released in Turkey between 1964 and 2014, 96 cotton varieties were analyzed using morphological and molecular markers. Morphological analysis was performed based on 4 fiber quality traits including fiber length, strength, fineness, and uniformity, and the mean values of each trait for each genotype were calculated using 2-year data. The results showed that most of the genotypes have long fiber length, very high fiber strength, coarse (45 genotypes) or average (50 genotypes) fiber fineness, and high uniformity. Twenty-six simple sequence repeat (SSR) markers and 14 markers linked to quantitative trait loci (QTLs) for fiber quality traits produced a total of 103 alleles, with an average of 2.57 alleles per locus ranging from 80 bp to 300 bp products, with an average polymorphism information content (PIC) value of 0.233. Markers DPL513 and DPL431 (among 26 SSR markers) and markers CIR246 and BNL4108 (among 14 molecular markers) were found to be very informative, with 0.724, 0.663, 0.749, and 0.583 PIC values, respectively. The combined morphological and molecular data analysis resulted in more than 8 clades using the unweighted pair group method with arithmetic average (UPGMA). The upland cotton varieties were distinctly separated from the lowland cotton variety Maydos Yerlisi (Gossypium herbaceum L.). Within the upland cotton varieties, the Egyptian cotton variety Giza 70 (G. barbadense L.) was distinctly separated from commercial cotton varieties of Turkey (G. hirsutum L.), as revealed by both morphological and molecular dendrograms. Principal component analysis (PCA) derived from combined data was in agreement with UPGMA analysis. It is concluded that commercial Turkish cotton varieties have a good genetic diversity with high fiber quality, considering the upland cotton's narrow genetic structure. These results can provide a useful guide for selecting specific germplasm with distinct genetic backgrounds in cotton breeding programs.Öğe Synthesis, characterization and antioxidant activity of chitosan Schiff base derivatives bearing (-)-gossypol(Elsevier Sci Ltd, 2020) Beyazit, Neslihan; Cakran, Halide Sinem; Cabir, Ali; Akiscan, Yasar; Demetgul, CahitIn this work, two new chitosan-Schiff base derivatives (HCS-GSP and LCS-GSP) were synthesized by the condensation reaction of high molecular weight chitosan (HCS) and low molecular weight chitosan (LCS) with (-)-gossypol (GSP), respectively. For this purpose, racemic gossypol was isolated from cotton seeds and it was further enantiomerically purified by diastereomeric resolution technique using L-tryptophan methyl ester hydrochloride. Then, chitosan polymers were derivatized with (-)-gossypol by the condensation reaction. The isolated and synthesized coumpounds were characterized by physical measurements and spectroscopic methods (elemental analysis C,H,N, Uv-vis, FT-IR, 1H&13C NMR and TG/DTG/DTA). The antioxidant activity of high molecular weight chitosan (HCS), low molecular weight chitosan (LCS) and their gossypol derivatives was evaluated as radical scavengers against 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH). The results showed that both of the chitosan-gossypol derivatives (HCS-GSP and LCS-GSP) had a better ability to scavenging DPPH radical (IC50, 12 mu g/mL and 16 mu g/mL, respectively) than its unmodified chitosan.
