Tolerance capacity of Turkish genotypes of barley (Hordeum vulagare L.) for cadmium stress

摘要

Aim : Elevated levels of heavy metals in agricultural soils result in significant contamination of food in Turkey, where cadmium toxicity is currently one of the most serious environmental issues. This study was undertaken to screen the various Turkish genotypes of barley for their sensitivity/tolerance towards cadmium stress.Methodology : Short-term experiments involving plant exposure to different Cd concentrations (0-100 mu M) were conducted to evaluate the response of ten barley genotypes (viz., Aydanhanlm, Bilgi-91, Cildir-02, Erginel-90, Ince-04, Kalayci-97, Keser, Larende, ozdemir-05, Tarm-92) under hydroponic conditions. Seed germination, seedling growth and Cd accumulation in plant tissues were taken as the criteria to evaluate the comparative genotypic response to Cd stress.Results : Cd-induced stress significantly decreased seed germination percentage in all genotypes and the effect was dose dependent. At 100 mu M Cd stress, genotypes Keser and Aydanhanim showed the maximum (46%) and minimum (12%) loss respectively, compared with the control. Root length was reduced by 68% and 30%, while shoot length declined by 44% and 11% in these genotypes, respectively. Similarly, the loss of root and shoot biomass was maximum in genotype Keser and minimum in Aydanhanim. However, genotype Aydanhanim accumulated the maximum (5.96 mu g g(-1) d.wt.), whereas Keser retained the minimum (5.41 mu g g(-1) d.wt.) amount of Cd in their roots at 100 mu M. Cd accumulation in shoot also displayed a similar genotypic difference.Interpretation : Based on the above observations, Aydanhanlm was Cd-tolerant, while Keser was most susceptible among the genotypes studied. Thus, genotype Aydanhanim has a promise to be a suitable candidate for phytoremediation of Cd-contaminated sites.