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Öğe Allelopathic Potential of Rapeseed Cultivars on Germination and Seedling Growth of Weeds(Asian Journal Of Chemistry, 2009) Uremis, I.; Arslan, M.; Sangun, M. K.; Uygur, V.; Isler, N.Allelopathic suppression of weeds is receiving greater attention as a possible alternative for weed management. Rapeseed (Brassica napus L., var. oleifera) contains allelochemicals that inhibits germination and growth of weed species. Allelopathic potential of 25 rapeseed cultivars on the seed germination, shoot and root growth of Amaranthus retroflexus L. (redroot pigweed). Solanum nigrum L. (black nightshade), Portulaca oleracea L. (common purslane), Physalis angulata L. (cutleaf, ground cherry) and Echinochloa colonum (L.) Link. (junglerice) were investigated with shoot and root extracts. All rapeseed cultivars examined inhibited seed germination, shoot and root growth of tested weed species. However, inhibition rates significantly varied among rapeseed cultivars. Significant reductions in seed germination, shoot and root growths were observed as the extract concentration increased. Extracts from both above and below ground parts of rapeseed had inhibitory effect on the tested weed species, but shoot extracts had slightly higher inhibition rates than that of root extracts. Root exudates had also inhibited germination of the tested weed species, but inhibitory effects are not as high as shoot and root extracts. Relative to the germination inhibition of weed seeds, the rapeseed cultivars were categorized as having highly, moderately and low allelopathic potential. Cultivar Westar was found to be highly allelopathic while cultivars Jumbuck, Tobin, Lisoune and Galant were found to be less allelopathic on the tested weed species. Rapeseed cultivars differed in isothiocyanate benzyl and isothiocyanate allyl. Cultivars containing higher level of isothiocyanate benzyl and isothiocyanate allyl had stronger allelopathic capacity. The result of this study showed that a great deal of success could be obtained by incorporation of highly allelopathic rapeseed cultivars into crop rotations to control weeds.Öğe THE CADMIUM PHYTOEXTRACTION EFFICIENCY OF SCMTII GENE BEARING TRANSGENIC TOBACCO PLANT(Taylor & Francis Ltd, 2010) Daghan, H.; Arslan, M.; Uygur, V.; Koleli, N.; Eren, A.Cadmium pollution is a serious world-wide problem affecting the human health and the environmental quality. Phytoremediation, the use of green plants to remove, sequester or detoxify pollutants offers an environmentally-friendly alternative to engineering-based methods for remediation. The T2 generations of the ScMTII gene bearing transgenic and non-transgenic tobacco plants were grown hydroponically in Hoagland nutrition solution containing 0, 5 and 10 mg/L Cd in controlled growth room to determine their ability to uptake and accumulate Cd within the shoots and roots. There were no significant shoot and root thy weight differences between transgenic and non-transgenic tobacco plants. The ScMTII gene bearing transgenic tobacco plant accumulated 19.8% higher Cd than the non-transgenic tobacco plant in the above ground parts of the plant during the two weeks exposure period in hydroponic culture. In non-transgenic plant, however, Cd is accumulated mainly in the roots. The results of current study indicate that the use of the ScMTII gene bearing transgenic tobacco plant for Cd phytoremediation is limited. Further studies are needed to test the effectiveness of the ScMTII gene for phytoextraction of other heavy metal ions.Öğe The Effects of composted poultry wastes on nitrogen mineralization and biological activity in a silt loam soil(2006) Kara, E.E.; Uygur, V.; Erel, A.Poultry manure or its compost are rich in plant nutrients and have a special potential to meet N and P requirements of agricultural plants. A laboratory study was carried out for 84 days at 30°C to asses the effect of application rate of composted poultry manure on soil respiration, dehydrogenase activity and nitrogen mineralization in a silt loam soil. Poultry compost rates were 0, 20, 40 and 60 Mg ha-1. Soil biological characteristics such as CO2 production, dehydrogenase activity and mineralization of organic-N into NH4+-N and NO3--N were determined on daily base during the first week and then in week interval. The results showed that CO2 production, dehydrogenase activity and mineral nitrogen of soils increased with respect to application rate of poultry compost. The mineralization rate was remarkably high in the first weeks and the mineralized-ammonium was immediately converted into NO3--N that accumulated during the course of experiment. Therefore, it is suggested that organic residues having narrow C:N ratio should not be applied at high amounts when there is no requirement for N by a growing crop. © 2006 Asian Network for Scientific Information.Öğe Yield responses of cauliflower (Brassica oleracea L. var. Botrytis) to different water and nitrogen levels in a Mediterranean coastal area(Taylor & Francis As, 2011) Bozkurt, S.; Uygur, V.; Agca, N.; Yalcin, M.Global warming along with the increasing population and fresh water shortages necessitates a specific fertilization programme under water-scarce conditions. This study was conducted to investigate the effects of different irrigation and nitrogen levels on yield, growth components and water use characteristics of cauliflower (Brassica oleracea L. var. Botrytis cv. Tetris-F-1) cultivated in a field for three consecutive years from 2005 to 2007 in the Eastern Mediterranean region of Turkey. Four irrigation (Kcp) levels with a drip irrigation system based on adjustment coefficients (0, 0.75, 1.0 and 1.25) of pan evaporation were used. Nitrogen (N) treatments were consisted of four different nitrogen rates (0, 75, 150 and 225 kg N ha(-1)). The following yield and quality parameters were determined: curd weight, curd diameters, number of leaves per crop, above ground biomass (AGB) and curd/AGB ratio. Fertilizer use efficiency (FUE) and leaf mineral contents were also determined to clarify the productivity of N treatments. According to the results; the amount of irrigation water and/or total received water affects the plant water consumption, consequently, crop yield in a field grown cauliflower. The highest yield was obtained in Kcp(1.0) irrigation level which represents full irrigation treatment. The excess water applications had negative effect on yield and AGB of cauliflower. Highest yield was obtained at 225 kg N ha(-1). The water use efficiency and irrigation water use efficiency values increased with decreasing irrigation rate. However, lower Kcp coefficients resulted in lower total yield. The FUE in irrigation treatments showed linear increases from non irrigation to full irrigation plots. However, excessive irrigation caused a decrease in FUE. It can be recommended that the Kcp1.0 crop-pan coefficient with 225 kg ha(-1) nitrogen application can be used to achieve the highest yield for field grown cauliflower in the Eastern Mediterranean coastal region of Turkey.
