Yasemin Coskun

Efficient Plant Regeneration with Arabinogalactan-Proteins on Various Ploidy Levels of Cereals

Abstract To determine the most effective dose of arabinogalactan-protein (AGP) in regeneration medium, mature embryos of genotypes in three different ploidy levels ( Triticum aestivum L. cv . Ikizce-96, Triticum durum Desf. cv . Mirzabey and Hordeum vulgare L. cv. Tokak) were used to establish an efficient plant regeneration system for cereals. Percentage of callus production, capacity of regeneration were calculated, and also culture effect, root, stem, and total plant length of regenerant plants were observed in six different regeneration media (MS control, MS+2, 5, 7, 10, 12 mg L −1 AGP) in these three different genotypes. According to the results, the highest amount of callus production was found in Ikizce-96 as 93.75% using 5 mg L −1 dicamba and 1 mg L −1 kinetin in induction medium. However, the most improved callus was observed in diploid barley Tokak as 179.95 mg in weight and 6.18 mm in diameter, respectively. The highest regeneration capacity was observed in the dose of 5 mg L −1 AGP in MS of all the genotypes and hexaploid wheat Ikizce-96 gave the best results with the highest regeneration capacity and culture effects (94.86 and 92.5%) in the same dose of AGP. These results indicated that effective dose of AGP in regeneration medium increase plant regeneration in calli derived from cereal mature embryos.

Response of maize (Zea mays L. saccharata Sturt) to different concentration treatments of deltamethrin.

The aim of this study was to investigate the effect of the deltamethrin pesticide on the biological properties of maize (Zea mays L. saccharata Sturt). Maize seeds were exposed to environmentally relevant dosages (0.01, 0.05, 0.1 and 0.5 ppm) of deltamethrin. On the 7th day of germination, morphological, anatomical and physiological responses were determined. All seedling growth characters were decreased with increasing deltamethrin levels. The most negative effect on the radicle length of maize was observed by the highest deltamethrin concentration with a 61% decrease (P <0.05). Both stomatal density and stomatal dimension reduction were caused by increasing concentrations of deltamethrin. Moreover, the pigments like chlorophyll a, chlorophyll b, total chlorophyll and caretonoids decreased with the increase in deltamethrin concentration. Conversely, anthocyanin and proline content increased in parallel with deltamethrin concentration. As a result, all morphological traits and pigments except for proline and anthocyanin were significantly reduced with an increase in pesticide concentration, compared to control (P <0.05).

Mannitol Application Alleviates Boron Toxicity in Wheat Seedlings

Boron (B) toxicity is a considerable mineral nutritional problem for crop production in arid and semi-arid regions worldwide. The effect of mannitol (M) in wheat seedlings that are tolerant and sensitive to excessive B was studied to reduce B toxicity symptoms. Plants were grown in a peat with different concentrations of boric acid (0, 30, 45, 60 mg kg−1) and treated additionally with M (0, 1, 5, 10 g kg−1). Seedlings grown for 8 weeks were harvested for root length, shoot length, and dry-weight measurements and analyzed for B content of leaves. Compared with control groups (no boric acid treatment), B toxicity caused reductions in root length, shoot length, and dry weight of both wheat cultivars. Significant increases on growth parameters were observed under B treatments, the greatest with 1 g kg−1 M application in a tolerant bread cultivar. On the other hand, 10 g kg−1 M application under 60 mg kg−1 B treatment gave also good results on root length in a sensitive durum cultivar. Significant decreases in leaf B content were observed under B treatments with all M applications in both wheat cultivars, the greatest with 5 g kg−1 M application. The results suggest that M applications may have a possible role in overcoming in B toxicity in wheat grown in the field.

The examination of Na-Ca effect on some qualitative and quantitative characters in durum wheat plants

The effect of salt stress (NaCl) on shoot height (cm), root length (cm), dry and fresh weight (g), chlorophyll a and b, total chlorophyll (mg -1 ) and carotenoid amount was investigated in this study. In addition, the positive effects of Ca +2 (20 mM) were also investigated. Triticum durum Desf. Mirzabey, Kunduru-1149, and DH-6 and DH-8, derived from Kunduru-1149 using wide hybridization, were used as plant materials in this study. Arnon-Hoagland solution was used as food source for the plants and various NaCl concentrations (0, 50, 150 and 200 mM) and Ca +2 (as CaCl 2 ) were added to Arnon-Hoagland solution. The research was completed at the end of the fifth week and the effect of NaCl on the root length of genotypes was found to be significant (P<0.05). Ca +2 caused an increase in root length in all NaCl applications, except for the 200 mM NaCl, whereas shoot height decreased with increasing salt concentration, except for the 50 mM NaCl. This character also increased with Ca +2 application significantly. Dry and fresh weight of the plant decreased with increasing salt concentration. Ca +2 ameliorated dry and fresh weight of the plant at 50 mM NaCl in all the genoypes and NaCl doses, except for the Kunduru-1149 and DH-6. The highest increase in total chlorophyll amount was found in 50 mM NaCl + CaCl 2 in DH-8 (from 17.29 to 20.14 mg g -1 ). However, the rate of increase in the amount of carotenoid by the addition of Ca +2 was also determined for each genotype. Key words : Triticum durum Desf., salinity, calcium, chlorophyll, carotenoid.