Aluminium (Al) toxicity is one of the major limiting factors for barley production on acid soils. It inhibits root cell division and elongation, thus reducing water and nutrient uptake, consequently resulting in poor ...Aluminium (Al) toxicity is one of the major limiting factors for barley production on acid soils. It inhibits root cell division and elongation, thus reducing water and nutrient uptake, consequently resulting in poor plant growth and yield. Plants tolerate Al either through external resistance mechanisms, by which Al is excluded from plant tissues or internal tolerance mechanisms, conferring the ability of plants to tolerate Al ion in the plant symplasm where Al that has permeated the plas- malemma is sequestered or converted into an innocuous form. Barley is considered to be most sensitive to Al toxicity among cereal species. Al tolerance in barley has been assessed by several methods, such as nutrient solution culture, soil bioassay and field screening. Genetic and molecular mapping research has shown that Al tolerance in barley is controlled by a single locus which is located on chromosome 4H. Molecular markers linked with Al tolerance loci have been identified and validated in a range of diverse populations. This paper reviews the (1) screening methods for evaluating Al tolerance, (2) genetics and (3) mechanisms underlying Al tolerance in barley.展开更多
Soil samples collected from several acid soils in Guangdong, Fujian, Zhejiang and Anhui provinces of the southern China were employed to characterize the chemical species of aluminum ions in the soils. The proportio...Soil samples collected from several acid soils in Guangdong, Fujian, Zhejiang and Anhui provinces of the southern China were employed to characterize the chemical species of aluminum ions in the soils. The proportion of monomeric inorganic Al to total Al in soil solution was in the range of 19% to 70%, that of monomeric organic Al (Al OM) to total Al ranged from 7.7% to 69%, and that of the acid soluble Al to total Al was generally smaller and was lower than 20% in most of the acid soils studied. The Al OM concentration in soil solution was positively correlated with the content of dissolved organic carbon (DOC) and also affected by the concentration of Al 3+ . The complexes of aluminum with fluoride (Al F) were the predominant forms of inorganic Al, and the proportion of Al F complexes to total inorganic Al increased with pH. Under strongly acid condition, Al 3+ was also a major form of inorganic Al, and the proportion of Al 3+ to total inorganic Al decreased with increasing pH. The proportions of Al OH and Al SO 4 complexes to total inorganic Al were small and were not larger than 10% in the most acid soils. The concentration of inorganic Al in solution depended largely on pH and the concentration of total F in soil solution. The concentrations of Al OM, Al 3+ ,Al F and Al OH complexes in topsoil were higher than those in subsoil and decreased with the increase in soil depth. The chemical species of aluminum ions were influenced by pH. The concentrations of Al OM, Al 3+ , Al F complexes and Al OH complexes decreased with the increase in pH.展开更多
Individual and combined effects of Cu, Pb, Zn and Cd on N mineralization, urease and phosphatase were examined in a Typic Udic Ferrisol in laboratory by employing an uniform design and a single factor design.Soil poll...Individual and combined effects of Cu, Pb, Zn and Cd on N mineralization, urease and phosphatase were examined in a Typic Udic Ferrisol in laboratory by employing an uniform design and a single factor design.Soil pollution caused by heavy metals inhibited N mineralization (No value) and urease and phosphatase activities. The combined pollution of metals alleviated their toxicity to N mineralization to some extent,whereas aggravated the toxicity to urease and phosphatase. Phosphorous application could mitigate the toxic effect of heavy metals on phosphatase activities, while alleviating effect of N application on the toxicity of heavy metals to urease was inconsistent. However, the mitigating effect of the fertilizers was limited in heavily polluted soils.展开更多
KCl, CaCl2, NH4Cl, NaCl, K2SO4 and KF solutions were used for studying the effects of canons and anions on the dissolution of aluminum and the distribution of aluminum forms respectively. Power of exchanging and relea...KCl, CaCl2, NH4Cl, NaCl, K2SO4 and KF solutions were used for studying the effects of canons and anions on the dissolution of aluminum and the distribution of aluminum forms respectively. Power of exchanging and releasing aluminum of four kinds of canons was in the decreasing order Ca2+ >K+ >NH+4 >Na+.The dissolution of aluminum increased with the canon concentration. The adsorption affinity of various soils for aluminum was different. The aluminum in the soil with a stronger adsorption affinity was difficult to be exchanged and released by canons. The Al-F complexes were main species of inorganic aluminum at a low concentration of canons, while Al3+ became major species of inorganic aluminum at a high concentration of canons. The results on the effect of anions indicated that the concentrations of total aluminum, three kinds of inorganic aluminum (Al3+, Al-F and Al-OH complexes) and organic aluminum complexes (Al-OM)when SO2-4 was added into soil suspension were lower than those when Cl- was added. The dissolution of aluminum from soils and the distribution of aluminum forms in solution were edicted by the adsorption of Fon the soil. For soils with strong affinty for F- , the concentrations of the three inorganic aluminum species in soil solution after addition of F- were lower than those after addition of Cl-; but for soils with weak affinity for F- , the concentrations of Al3+ and Al-OM were lower and the concentrations of Al-F complexes and total inorganic aluminum after addition of F- were higher than those after addition of Cl-. The increase of F- concentration in soil solution accelerated the dissolution of aluminum from soils.展开更多
Aluminium phosphide is a rodenticide widely used in agriculture to protect grains and foods. Poisoning with this product represents a real problem in developing countries, as an interested young people and it causes h...Aluminium phosphide is a rodenticide widely used in agriculture to protect grains and foods. Poisoning with this product represents a real problem in developing countries, as an interested young people and it causes high mortality. Aims of this study are to analysis epidemiological aspects, clinics, therapeutic, outcome of this acute poisoning and determine the factors of mortality. It is a retrospective study, concerned 47 patients intoxicated by the Aluminium phosphide between January 2009 and December 2012. It represents 23.4% of all poisonings. The mean age was 24.5 years with a female predominance （63.8%）. The poisoning was in a suicidal goal in 95.7% of cases. The mean ingested quantity was 3 grams. The initial clinical picture was dominated by vomiting, abdominal pain, shock and disorders of consciousness in 57.4%, 48.9%, 31.9% and 21.3%, respectively. Electrocardiogram abnormalities were observed in 38.3% of cases. Increase of Troponin was observed in 27.7% of cases. 36.2% of patients were intubated and ventilated and 40.4% have been placed under vasoactive drugs. The mortality rate was 38.3%. The prognostic factors were： delay of management, potassium disorders, elevated of Troponin, hypotension, tachycardia, need for mechanical ventilation, vasoactive drugs and shock. To improve the prognosis, the management should be rapid and the governement should focus more on prevention, so the aluminium phosphide will not be avaible to general population.展开更多
It is imperative to choose some low cost, available and effective ameliorants to correct soil acidity in southern China for sustainable agriculture. The present investigation dealt with the possible role of industrial...It is imperative to choose some low cost, available and effective ameliorants to correct soil acidity in southern China for sustainable agriculture. The present investigation dealt with the possible role of industrial byproducts, i.e., coal fly ash （CFA）, alkaline slag （AS）, red mud （RM） and phosphogypsum （PG） in correcting acidity and aluminum （Al） toxicity of soils under tea plantation using an indoor incubation experiment. Results indicated that CFA, AS and RM increased soil pH, while PG decreased the pHs of an Ultisol and an Alfisol. The increment of soil pH followed the order of RM 〉 AS 〉 CFA. All the industrial byproducts invariably decreased exchangeable Al and hence increased exchangeable Ca, Mg, K and Na and effective cation exchange capacity. RM, AS and lime decreased total soluble Al, exchangeable Al and organically bound Al. Formation and retention of hydroxyl-Al polymers were the principal mechanism through which Al phytotoxicity was alleviated by application of these amendments. In addition, the heavy metal contents in the four industrial byproducts constituted a limited environmental hazard in a short time at the rates normally used in agriculture. Therefore, the short-term use of the byproducts, especially AS and RM, as amendments for soil acidity and AI toxicity in acid soils may be a potential alternative to the traditional use of mined gypsum and lime.展开更多
Aluminum(Al)is the most abundant metal element in the earth’s crust.On acid soils,at pH 5.5 or lower,part of insoluble Al-containing minerals become solubilized into soil solution,with resultant highly toxic effects ...Aluminum(Al)is the most abundant metal element in the earth’s crust.On acid soils,at pH 5.5 or lower,part of insoluble Al-containing minerals become solubilized into soil solution,with resultant highly toxic effects on plant growth and development.Nevertheless,some plants have developed Al-tolerance mechanisms that enable them to counteract this Al toxicity.One such well-documented mechanism is the Al-induced secretion of organic acid anions,including citrate,malate,and oxalate,from plant roots.Once secreted,these anions chelate external Al ions,thus protecting the secreting plant from Al toxicity.Genes encoding the citrate and malate transporters responsible for secretion have been identified and characterized,and accumulating evidence indicates that regulation of the expression of these transporter genes is critical for plant Al tolerance.In this review,we outline the recent history of research into plant Al-tolerance mechanisms,with special emphasis on the physiology of Al-induced secretion of organic acid anions from plant roots.In particular,we summarize the identification of genes encoding organic acid transporters and review current understanding of genes regulating organic acid secretion.We also discuss the possible signaling pathways regulating the expression of organic acid transporter genes.展开更多
基金Project supported by NSW Agricultural Genomic Centre and theGrains Research and Development Corporation (GRDC) of Australia(No. UT8)
文摘Aluminium (Al) toxicity is one of the major limiting factors for barley production on acid soils. It inhibits root cell division and elongation, thus reducing water and nutrient uptake, consequently resulting in poor plant growth and yield. Plants tolerate Al either through external resistance mechanisms, by which Al is excluded from plant tissues or internal tolerance mechanisms, conferring the ability of plants to tolerate Al ion in the plant symplasm where Al that has permeated the plas- malemma is sequestered or converted into an innocuous form. Barley is considered to be most sensitive to Al toxicity among cereal species. Al tolerance in barley has been assessed by several methods, such as nutrient solution culture, soil bioassay and field screening. Genetic and molecular mapping research has shown that Al tolerance in barley is controlled by a single locus which is located on chromosome 4H. Molecular markers linked with Al tolerance loci have been identified and validated in a range of diverse populations. This paper reviews the (1) screening methods for evaluating Al tolerance, (2) genetics and (3) mechanisms underlying Al tolerance in barley.
文摘Soil samples collected from several acid soils in Guangdong, Fujian, Zhejiang and Anhui provinces of the southern China were employed to characterize the chemical species of aluminum ions in the soils. The proportion of monomeric inorganic Al to total Al in soil solution was in the range of 19% to 70%, that of monomeric organic Al (Al OM) to total Al ranged from 7.7% to 69%, and that of the acid soluble Al to total Al was generally smaller and was lower than 20% in most of the acid soils studied. The Al OM concentration in soil solution was positively correlated with the content of dissolved organic carbon (DOC) and also affected by the concentration of Al 3+ . The complexes of aluminum with fluoride (Al F) were the predominant forms of inorganic Al, and the proportion of Al F complexes to total inorganic Al increased with pH. Under strongly acid condition, Al 3+ was also a major form of inorganic Al, and the proportion of Al 3+ to total inorganic Al decreased with increasing pH. The proportions of Al OH and Al SO 4 complexes to total inorganic Al were small and were not larger than 10% in the most acid soils. The concentration of inorganic Al in solution depended largely on pH and the concentration of total F in soil solution. The concentrations of Al OM, Al 3+ ,Al F and Al OH complexes in topsoil were higher than those in subsoil and decreased with the increase in soil depth. The chemical species of aluminum ions were influenced by pH. The concentrations of Al OM, Al 3+ , Al F complexes and Al OH complexes decreased with the increase in pH.
文摘Individual and combined effects of Cu, Pb, Zn and Cd on N mineralization, urease and phosphatase were examined in a Typic Udic Ferrisol in laboratory by employing an uniform design and a single factor design.Soil pollution caused by heavy metals inhibited N mineralization (No value) and urease and phosphatase activities. The combined pollution of metals alleviated their toxicity to N mineralization to some extent,whereas aggravated the toxicity to urease and phosphatase. Phosphorous application could mitigate the toxic effect of heavy metals on phosphatase activities, while alleviating effect of N application on the toxicity of heavy metals to urease was inconsistent. However, the mitigating effect of the fertilizers was limited in heavily polluted soils.
文摘KCl, CaCl2, NH4Cl, NaCl, K2SO4 and KF solutions were used for studying the effects of canons and anions on the dissolution of aluminum and the distribution of aluminum forms respectively. Power of exchanging and releasing aluminum of four kinds of canons was in the decreasing order Ca2+ >K+ >NH+4 >Na+.The dissolution of aluminum increased with the canon concentration. The adsorption affinity of various soils for aluminum was different. The aluminum in the soil with a stronger adsorption affinity was difficult to be exchanged and released by canons. The Al-F complexes were main species of inorganic aluminum at a low concentration of canons, while Al3+ became major species of inorganic aluminum at a high concentration of canons. The results on the effect of anions indicated that the concentrations of total aluminum, three kinds of inorganic aluminum (Al3+, Al-F and Al-OH complexes) and organic aluminum complexes (Al-OM)when SO2-4 was added into soil suspension were lower than those when Cl- was added. The dissolution of aluminum from soils and the distribution of aluminum forms in solution were edicted by the adsorption of Fon the soil. For soils with strong affinty for F- , the concentrations of the three inorganic aluminum species in soil solution after addition of F- were lower than those after addition of Cl-; but for soils with weak affinity for F- , the concentrations of Al3+ and Al-OM were lower and the concentrations of Al-F complexes and total inorganic aluminum after addition of F- were higher than those after addition of Cl-. The increase of F- concentration in soil solution accelerated the dissolution of aluminum from soils.
文摘Aluminium phosphide is a rodenticide widely used in agriculture to protect grains and foods. Poisoning with this product represents a real problem in developing countries, as an interested young people and it causes high mortality. Aims of this study are to analysis epidemiological aspects, clinics, therapeutic, outcome of this acute poisoning and determine the factors of mortality. It is a retrospective study, concerned 47 patients intoxicated by the Aluminium phosphide between January 2009 and December 2012. It represents 23.4% of all poisonings. The mean age was 24.5 years with a female predominance （63.8%）. The poisoning was in a suicidal goal in 95.7% of cases. The mean ingested quantity was 3 grams. The initial clinical picture was dominated by vomiting, abdominal pain, shock and disorders of consciousness in 57.4%, 48.9%, 31.9% and 21.3%, respectively. Electrocardiogram abnormalities were observed in 38.3% of cases. Increase of Troponin was observed in 27.7% of cases. 36.2% of patients were intubated and ventilated and 40.4% have been placed under vasoactive drugs. The mortality rate was 38.3%. The prognostic factors were： delay of management, potassium disorders, elevated of Troponin, hypotension, tachycardia, need for mechanical ventilation, vasoactive drugs and shock. To improve the prognosis, the management should be rapid and the governement should focus more on prevention, so the aluminium phosphide will not be avaible to general population.
基金Supported by the International Foundation of Science(No.C/4073-1)the National"Eleventh Five Years Plan"Key Project on Science and Technology of China(Nos.2006BAD05B02 and 2009BADC6B02)
文摘It is imperative to choose some low cost, available and effective ameliorants to correct soil acidity in southern China for sustainable agriculture. The present investigation dealt with the possible role of industrial byproducts, i.e., coal fly ash （CFA）, alkaline slag （AS）, red mud （RM） and phosphogypsum （PG） in correcting acidity and aluminum （Al） toxicity of soils under tea plantation using an indoor incubation experiment. Results indicated that CFA, AS and RM increased soil pH, while PG decreased the pHs of an Ultisol and an Alfisol. The increment of soil pH followed the order of RM 〉 AS 〉 CFA. All the industrial byproducts invariably decreased exchangeable Al and hence increased exchangeable Ca, Mg, K and Na and effective cation exchange capacity. RM, AS and lime decreased total soluble Al, exchangeable Al and organically bound Al. Formation and retention of hydroxyl-Al polymers were the principal mechanism through which Al phytotoxicity was alleviated by application of these amendments. In addition, the heavy metal contents in the four industrial byproducts constituted a limited environmental hazard in a short time at the rates normally used in agriculture. Therefore, the short-term use of the byproducts, especially AS and RM, as amendments for soil acidity and AI toxicity in acid soils may be a potential alternative to the traditional use of mined gypsum and lime.
基金supported by the National Natural Science Foundation of China(Nos.31572193,31760615,and 31760584)111 Project(No.B14027)the Changjiang Scholars Program of China
文摘Aluminum(Al)is the most abundant metal element in the earth’s crust.On acid soils,at pH 5.5 or lower,part of insoluble Al-containing minerals become solubilized into soil solution,with resultant highly toxic effects on plant growth and development.Nevertheless,some plants have developed Al-tolerance mechanisms that enable them to counteract this Al toxicity.One such well-documented mechanism is the Al-induced secretion of organic acid anions,including citrate,malate,and oxalate,from plant roots.Once secreted,these anions chelate external Al ions,thus protecting the secreting plant from Al toxicity.Genes encoding the citrate and malate transporters responsible for secretion have been identified and characterized,and accumulating evidence indicates that regulation of the expression of these transporter genes is critical for plant Al tolerance.In this review,we outline the recent history of research into plant Al-tolerance mechanisms,with special emphasis on the physiology of Al-induced secretion of organic acid anions from plant roots.In particular,we summarize the identification of genes encoding organic acid transporters and review current understanding of genes regulating organic acid secretion.We also discuss the possible signaling pathways regulating the expression of organic acid transporter genes.
