It is well known that salinity has badly effect on plant growth all over the world and greatly reduces crop production in the affected regions.Selenium can function as an antioxidant in plants and also in low concentr...It is well known that salinity has badly effect on plant growth all over the world and greatly reduces crop production in the affected regions.Selenium can function as an antioxidant in plants and also in low concentration can promotes plant growth and produce tolerance against stress.This study was conducted in order to determine the effects of selenium(Se)application(0,4,8 and 16 mg L^-1)on phenylalanine ammonia-lyase(PAL)activity,phenol leakage and total phenolic content of garlic under salt stress(0,30,60 and 90 mM NaCl).The highest PAL activity was recorded at 60 and 90 mM NaCl salinity with application of 8mg Se L^-1.Also,when Se was added to the salt-stress garlic,the level of phenol leakage was decreased significantly at two levels of NaCl concentration(by 52%and 40%at 30 mM NaCl with application of 4 and 16 mg Se L^-1,and by 50%at 90 mM NaCl with application of 4mg Se L^-1,respectively)in comparison to the salt-stressed garlic without Se.The results showed that Se can increase the salt tolerance of garlic by protecting the cell membrane against lipid peroxidation.The highest concentration of phenols was recorded at 90 mM NaCl salinity level with application of 4 and 8 mg Se L^-1,that respectively produced 59%and 51%higher phenols than control treatment without Se.So,application of optimal Se level can increase the potential of garlic in a medium with relatively high level of NaCl.展开更多
Selenium,which is an essential microelement for animals,positively affects growth and development of some plants by enhancing the activities of antioxidant enzyme.The study was conducted in order to determine the effe...Selenium,which is an essential microelement for animals,positively affects growth and development of some plants by enhancing the activities of antioxidant enzyme.The study was conducted in order to determine the effects of selenium(0,4,8 and 16 mg L^-1)on salt stress(0,30,60 and 90 mM NaCl)subjected garlic plants grown in hydroponics.According to results,salinity reduced chlorophyll index and carotenoid contents.Se application 8 mg L^-1 in 30 mM NaCl salinity and 4 mg L^-1 in 60 mM NaCl salinity significantly improved chlorophyll index and carotenoid contents,RWC was increased by application of 16 mg L^-1 Se under 90 mM NaCl,in garlic leaves.Also,with further increases in Se to the medium containing 30 mM NaCl,K concentration gradually increased in leaves.Analysis of Na content in leaves revealed that Na concentration increases with increasing salinity.Moreover,it is concluded that Se increase in K uptake and decrease in Na uptake under salt stress.展开更多
Chromium(Cr)-contaminated soils pose a great environmental risk, with high solubility and persistent leaching of Cr(Ⅵ). In this study, hydroxysulfate green rust(GR_(SO4)), with the general formula Fe(Ⅱ)_(4) Fe(Ⅲ)_(...Chromium(Cr)-contaminated soils pose a great environmental risk, with high solubility and persistent leaching of Cr(Ⅵ). In this study, hydroxysulfate green rust(GR_(SO4)), with the general formula Fe(Ⅱ)_(4) Fe(Ⅲ)_(2)(OH)_(12) SO_(4)·8 H_(2) O, was evaluated for its efficiency in Cr(Ⅵ) stabilization via Cr(Ⅵ) reduction to Cr(Ⅲ) in four representative Cr(Ⅵ)-spiked soils. The initial concentrations of phosphate buffer-extractable Cr(Ⅵ)(Cr(Ⅵ)b) in soils 1, 2, 3, and 4 were 382.4, 575.9, 551.3, and 483.7 mg kg^(-1), respectively. Reduction of Cr(Ⅵ) to Cr(Ⅲ) by structural Fe(Ⅱ)(Fe(Ⅱ)s) in GR_(SO4) in all studied soils was fast,wherein the application of GR_(SO4) markedly decreased the amount of Cr(Ⅵ)bat the Cr(Ⅵ)b/Fe(Ⅱ)s stoichiometric mole ratio of 0.33. The kinetics of Cr(Ⅵ)reduction by GR_(SO4) could not be determined as this reaction coincided with the release of Cr(Ⅵ) from soil during the experiment. The concentration of Cr(Ⅵ)bdecreased, as the Cr(Ⅵ)b/Fe(Ⅱ)s ratio decreased from 0.46 to 0.20, generally to below 10 mg kg^(-1). Back-transformation of the generated Cr(Ⅲ)was examined in the presence of manganese oxide birnessite at the birnessite/initial Cr(Ⅲ) mole ratio of 4.5. The results of batch tests showed that only 5.2% of the initial Cr(Ⅲ) was converted to Cr(Ⅵ) after two months, while under field capacity moisture conditions, less than 0.05% of the initial Cr(Ⅲ) was oxidized to Cr(Ⅵ) after six months. The results illustrated that remediation of Cr(Ⅵ)-contaminated soils would be fast, successful, and irreversible with an appropriate quantity of fresh GR_(SO_(4)).展开更多
文摘It is well known that salinity has badly effect on plant growth all over the world and greatly reduces crop production in the affected regions.Selenium can function as an antioxidant in plants and also in low concentration can promotes plant growth and produce tolerance against stress.This study was conducted in order to determine the effects of selenium(Se)application(0,4,8 and 16 mg L^-1)on phenylalanine ammonia-lyase(PAL)activity,phenol leakage and total phenolic content of garlic under salt stress(0,30,60 and 90 mM NaCl).The highest PAL activity was recorded at 60 and 90 mM NaCl salinity with application of 8mg Se L^-1.Also,when Se was added to the salt-stress garlic,the level of phenol leakage was decreased significantly at two levels of NaCl concentration(by 52%and 40%at 30 mM NaCl with application of 4 and 16 mg Se L^-1,and by 50%at 90 mM NaCl with application of 4mg Se L^-1,respectively)in comparison to the salt-stressed garlic without Se.The results showed that Se can increase the salt tolerance of garlic by protecting the cell membrane against lipid peroxidation.The highest concentration of phenols was recorded at 90 mM NaCl salinity level with application of 4 and 8 mg Se L^-1,that respectively produced 59%and 51%higher phenols than control treatment without Se.So,application of optimal Se level can increase the potential of garlic in a medium with relatively high level of NaCl.
文摘Selenium,which is an essential microelement for animals,positively affects growth and development of some plants by enhancing the activities of antioxidant enzyme.The study was conducted in order to determine the effects of selenium(0,4,8 and 16 mg L^-1)on salt stress(0,30,60 and 90 mM NaCl)subjected garlic plants grown in hydroponics.According to results,salinity reduced chlorophyll index and carotenoid contents.Se application 8 mg L^-1 in 30 mM NaCl salinity and 4 mg L^-1 in 60 mM NaCl salinity significantly improved chlorophyll index and carotenoid contents,RWC was increased by application of 16 mg L^-1 Se under 90 mM NaCl,in garlic leaves.Also,with further increases in Se to the medium containing 30 mM NaCl,K concentration gradually increased in leaves.Analysis of Na content in leaves revealed that Na concentration increases with increasing salinity.Moreover,it is concluded that Se increase in K uptake and decrease in Na uptake under salt stress.
基金the University of Tabriz,Iran for providing support。
文摘Chromium(Cr)-contaminated soils pose a great environmental risk, with high solubility and persistent leaching of Cr(Ⅵ). In this study, hydroxysulfate green rust(GR_(SO4)), with the general formula Fe(Ⅱ)_(4) Fe(Ⅲ)_(2)(OH)_(12) SO_(4)·8 H_(2) O, was evaluated for its efficiency in Cr(Ⅵ) stabilization via Cr(Ⅵ) reduction to Cr(Ⅲ) in four representative Cr(Ⅵ)-spiked soils. The initial concentrations of phosphate buffer-extractable Cr(Ⅵ)(Cr(Ⅵ)b) in soils 1, 2, 3, and 4 were 382.4, 575.9, 551.3, and 483.7 mg kg^(-1), respectively. Reduction of Cr(Ⅵ) to Cr(Ⅲ) by structural Fe(Ⅱ)(Fe(Ⅱ)s) in GR_(SO4) in all studied soils was fast,wherein the application of GR_(SO4) markedly decreased the amount of Cr(Ⅵ)bat the Cr(Ⅵ)b/Fe(Ⅱ)s stoichiometric mole ratio of 0.33. The kinetics of Cr(Ⅵ)reduction by GR_(SO4) could not be determined as this reaction coincided with the release of Cr(Ⅵ) from soil during the experiment. The concentration of Cr(Ⅵ)bdecreased, as the Cr(Ⅵ)b/Fe(Ⅱ)s ratio decreased from 0.46 to 0.20, generally to below 10 mg kg^(-1). Back-transformation of the generated Cr(Ⅲ)was examined in the presence of manganese oxide birnessite at the birnessite/initial Cr(Ⅲ) mole ratio of 4.5. The results of batch tests showed that only 5.2% of the initial Cr(Ⅲ) was converted to Cr(Ⅵ) after two months, while under field capacity moisture conditions, less than 0.05% of the initial Cr(Ⅲ) was oxidized to Cr(Ⅵ) after six months. The results illustrated that remediation of Cr(Ⅵ)-contaminated soils would be fast, successful, and irreversible with an appropriate quantity of fresh GR_(SO_(4)).
