Since it is unrealistic to do an experimental mixture assessment on every possible combination, mathematical model plays an important role in predicting the mixture toxicity. The present study is devoted to the furthe...Since it is unrealistic to do an experimental mixture assessment on every possible combination, mathematical model plays an important role in predicting the mixture toxicity. The present study is devoted to the further application of linear concentration addition（CA）-based model（LCA） and independent action（IA）-based model（LIA） to predict the non-interactive mixture toxicity. The 26 mixtures including 312 data points were used to evaluate the predictive powers of LCA and LIA models. The models were internally validated using the leave-one-out cross-validation and y-randomization test, and the external validations were evaluated by the test tests. Both LCA and LIA models agree well with the experimental values for all mixture toxicity, and present high internally（R2 and Q2 〉 0.98） and externally（Q2F1, Q2F2, and Q2F3 〉 0.99） predictive power. The use of LCA and LIA led to improved predictions compared to the estimates based on the CA and IA models. Both LCA and LIA were found to be appropriate methods for modeling toxicity of non-interactive chemical mixtures.展开更多
采用盆栽控制试验对黄土丘陵区白羊草在不同CO_2浓度(400和800μmol·mol^(-1))和施氮水平(0、2.5、5.0 g N·m^(-2)·a^(-1))条件下根际和非根际土壤水溶性有机碳(DOC}和水溶性有机氮(DON)的变化特征进行研究.结果表明:CO_...采用盆栽控制试验对黄土丘陵区白羊草在不同CO_2浓度(400和800μmol·mol^(-1))和施氮水平(0、2.5、5.0 g N·m^(-2)·a^(-1))条件下根际和非根际土壤水溶性有机碳(DOC}和水溶性有机氮(DON)的变化特征进行研究.结果表明:CO_2浓度升高对白羊草根际和非根际土壤DOC、水溶性总氮(DTN)、DON、水溶性铵态氮(NH_4^+-N)、水溶性硝态氮(NO_3^-N)含量均无显著影响.施氮显著提高了根际和非根际土壤DTN、NO_3^-N含量和根际土壤DON含量,显著降低了根际土壤DOC/DON.在各处理条件下,根际土壤DTN、NO_3^-N和DON含量均显著低于非根际土壤,根际土壤DOC/DON显著高于非根际土壤.短期CO_2浓度升高对黄土丘陵区土壤水溶性有机碳、氮含量无显著影响,而氮沉降的増加在一定程度上改善了土壤中水溶性氮素缺乏的状况,但并不足以满足植被对水溶性氮素的需求.展开更多
基金supported by the National Natural Science Foundation of China(21407032,21667013,51578171)Natural Science Foundation of Guangxi Province(2014GXNSFBA118233)Guilin Scientific Research and Technology Development Program(2016012505)
文摘Since it is unrealistic to do an experimental mixture assessment on every possible combination, mathematical model plays an important role in predicting the mixture toxicity. The present study is devoted to the further application of linear concentration addition（CA）-based model（LCA） and independent action（IA）-based model（LIA） to predict the non-interactive mixture toxicity. The 26 mixtures including 312 data points were used to evaluate the predictive powers of LCA and LIA models. The models were internally validated using the leave-one-out cross-validation and y-randomization test, and the external validations were evaluated by the test tests. Both LCA and LIA models agree well with the experimental values for all mixture toxicity, and present high internally（R2 and Q2 〉 0.98） and externally（Q2F1, Q2F2, and Q2F3 〉 0.99） predictive power. The use of LCA and LIA led to improved predictions compared to the estimates based on the CA and IA models. Both LCA and LIA were found to be appropriate methods for modeling toxicity of non-interactive chemical mixtures.
文摘采用盆栽控制试验对黄土丘陵区白羊草在不同CO_2浓度(400和800μmol·mol^(-1))和施氮水平(0、2.5、5.0 g N·m^(-2)·a^(-1))条件下根际和非根际土壤水溶性有机碳(DOC}和水溶性有机氮(DON)的变化特征进行研究.结果表明:CO_2浓度升高对白羊草根际和非根际土壤DOC、水溶性总氮(DTN)、DON、水溶性铵态氮(NH_4^+-N)、水溶性硝态氮(NO_3^-N)含量均无显著影响.施氮显著提高了根际和非根际土壤DTN、NO_3^-N含量和根际土壤DON含量,显著降低了根际土壤DOC/DON.在各处理条件下,根际土壤DTN、NO_3^-N和DON含量均显著低于非根际土壤,根际土壤DOC/DON显著高于非根际土壤.短期CO_2浓度升高对黄土丘陵区土壤水溶性有机碳、氮含量无显著影响,而氮沉降的増加在一定程度上改善了土壤中水溶性氮素缺乏的状况,但并不足以满足植被对水溶性氮素的需求.
文摘选择造林树种大叶相思(Acacia auriculiformis)和樟树(Cinnamomum camphora)为对象,采用开顶生长箱(open-top chamber,OTC)构建实验林,探讨镉(Cd)胁迫及其与大气CO_(2)浓度升高、氮(N)添加的复合作用对2种树木叶片N、P养分利用策略和Cd积累特征的影响。试验设5个处理:对照(CK)、加Cd[10 kg Cd/(hm^(2)·a)](Cd)、加Cd与加CO_(2)(700μmol/mol)(CdC)、加Cd与加N[100 kg N/(hm^(2)·a)](CdN)、加Cd加CO_(2)加N(CdCN)。处理约2.5 a后,测定两树种的成熟叶和衰老叶中N、磷(P)和Cd含量。结果表明,不同处理对两树种叶片P含量及P回收率均无显著影响,但显著影响叶片N含量及N回收率;CdN处理下两树种叶片N含量升高;Cd和CdN处理下樟树叶N回收率显著降低。Cd、CdC、CdN和CdCN处理下两树种叶片Cd积累浓度及樟树成熟叶中的Cd/N和Cd/P升高。大叶相思叶片N、P回收率显著高于樟树,Cd积累浓度显著低于樟树。速生豆科固氮树种大叶相思比普通非固氮树种樟树具有更好的N、P养分利用策略和抵御叶片积累Cd的能力,表明大叶相思可以作为Cd污染林地土壤生态修复的适宜树种。
