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    溶液Ca、K浓度和pH对烟草Cd毒性的影响

    Influence of Ca, K Concentration and pH Value in Solution on Cd Toxicity to Tobacco in Solution Culture

    • 摘要: 通过水培实验,利用逻辑斯蒂克分布模型研究了溶液中不同Ca、K浓度及pH条件下镉(Cd)对烟草的急性毒性.结果表明,随着溶液pH的升高,Cd对烟草根伸长的10%抑制浓度(EC10)及半抑制浓度(EC50)逐渐增加,也即Cd的毒性逐渐降低,溶液的pH与烟草Cd毒性EC10、EC50间呈显著的正相关关系,当溶液pH从4.52增加到8.10时,烟草根伸长的EC50增加了6.73倍.烟草Cd毒性EC10、EC50测定结果表明,当溶液Ca离子浓度 < 128.0 mg/L时,添加Ca离子浓度可以显著降低烟草Cd的毒性;与Ca不同,当溶液中K离子浓度 < 64.0 mg/L时,K离子浓度的增加并没有显著降低Cd的毒性,当溶液中K离子浓度 > 64.0 mg/L,溶液K离子浓度增加可以显著降低烟草Cd的毒性.在烟草Cd污染胁迫条件下,提高介质pH和增加介质中Ca、K离子的浓度是有效降低Cd毒性的措施之一.

       

      Abstract: The acute toxicity of cadmium (Cd) to tobacco cultivar (Nicotiana tabacum L.) as affected by calcium (Ca), potassium (K) concentrations and pH values was assessed by using Log-logistic distribution model in solution culture. The results showed that the 10% and half inhibitory concentration (EC10, EC50) of Cd toxicity increased with the increment of pH values in solution as determined by tobacco root elongation, which indicated that the toxicity of Cd to tobacco decreased with the increasing pH values in solution, a significantly positive correlation was observed between the ECs (s=10, 50) and pH values in solution. The half inhibitory concentration (EC50) of Cd toxicity to tobacco increased 6.73 times greater when the pH value increased from 4.52 to 8.10 in solution. The addition of Ca ion in solution could markedly decrease the Cd-toxicity to tobacco cultivar as assessed by EC10 and EC50 with an optimum maximum concentration of 128.0 mg/L. In terms of K ion, low concentration of K ion addition (<64.0 mg/L) could marginally decrease the toxicity of Cd to tobacco cultivar in solution as assessed by EC10, however, it could significantly decrease the Cd-toxicity to tobacco cultivar with greater concentration addition more than 64.0 mg/L in solution. Increasing pH and Ca, K concentration in culture matrix could significantly decrease toxicity of Cd to tobacco cultivars in Cd-polluted matrix.

       

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