Pulleniatina obliquiloculata shells from 16 core-top samples from the tropical Indo-Pacific Oceans are analyzed for the ratios of boron and cadmium to calcium(B/Ca and Cd/Ca). The B/Ca ratios show a very weak positive...Pulleniatina obliquiloculata shells from 16 core-top samples from the tropical Indo-Pacific Oceans are analyzed for the ratios of boron and cadmium to calcium(B/Ca and Cd/Ca). The B/Ca ratios show a very weak positive relationship with [B(OH)_4^-] and the dissolved carbonate species at the apparent calcification depth of P.obliquiloculata. The boron partition coefficients(K_D) between P. obliquiloculata B/Ca and seawater[B(OH)_4^-]/[HCO_3^-] distribute around 1.1×10^(-3)-1.3×10^(-3) with a mean value of(1.19±0.12)×10^(-3),and are significantly related to the nutrient concentration, especially phosphate. The lack of any clear correlation between the P. obliquiloculata B/Ca and seawater carbonate chemical parameters suggests that the physiochemical controls on boron incorporation are masked by the complexity of natural seawater condition. But the significant dependence of Ku on nutrient may likely be explained by a nutrient related growth-rate effect. Cd/Ca of P.obliquiloculata shows significant correlation with seawater phosphate concentration, and its partition coefficients(D_(cd)) are significantly related to temperature. A first-principle methodology of P. obliquiloculata B/Ca is applied;with the aid of Cd/Ca as a phosphate proxy and a constraint on K_D, to estimating sea water carbonate chemistry(e.g., pH). The results are fairly promising and allow us to propose the possibility to apply the combination of B/Ca and Cd/Ca proxies(and also Mg/Ca and δ^(18)O for estimating temperature and salinity) for the paleoreconstruction of seawater carbonate chemistry.展开更多
【目的】探明不同pH条件下Ca/Cd化学计量比对辣椒根系Cd吸收动态特征的影响,为提升辣椒的耐镉能力及降低产品镉污染风险提供理论依据。【方法】以香辣四号线椒种子为研究对象,采用水培法模拟不同pH土壤溶液(pH 5、pH 6、pH 7),设置不同C...【目的】探明不同pH条件下Ca/Cd化学计量比对辣椒根系Cd吸收动态特征的影响,为提升辣椒的耐镉能力及降低产品镉污染风险提供理论依据。【方法】以香辣四号线椒种子为研究对象,采用水培法模拟不同pH土壤溶液(pH 5、pH 6、pH 7),设置不同Ca/Cd化学计量关系(Cd+2 mM Ca、Cd+4 mM Ca、Cd+8 mM Ca、Cd+16 mM Ca、Cd+32 mM Ca),测定辣椒根系镉蓄积量、吸附量及吸收通量,研究不同pH条件下Ca^(2+)、Cd^(2+)交互作用对根系Cd吸收动态的影响。【结果】不同pH处理Cd蓄积量随Ca浓度增加而逐渐降低。pH 6条件下,Ca^(2+)对Cd^(2+)的竞争吸附影响最小,Cd蓄积量整体最高。pH 5条件下,竞争影响最大,Cd蓄积量整体最低,但根系表面Cd吸附量显著高于其他两个pH处理组。Ca/Cd化学计量比与单位面积根表Cd^(2+)的络合通量及吸收通量均呈负线性关系,单位面积根表Cd^(2+)络合量与吸收通量呈较好的正相关性,单位面积根表Cd^(2+)络合量对吸收通量的影响在pH 6时显著,Cd^(2+)的生物有效性更高,更易富集到植物体内。【结论】通过优化根际Ca/Cd化学计量比并维持弱酸性环境(pH 5),可最大限度抑制辣椒对Cd^(2+)的吸收,为安全生产低镉辣椒的农业实践提供技术参考。展开更多
基金The National Natural Science Foundation of China(NSFC)and NSFC-Shandong Joint Fund for Marine Science Research Centers under contract Nos 41606049,U1606401 and 41376054the China Postdoctoral Science Foundation under contract No.2015M581658
文摘Pulleniatina obliquiloculata shells from 16 core-top samples from the tropical Indo-Pacific Oceans are analyzed for the ratios of boron and cadmium to calcium(B/Ca and Cd/Ca). The B/Ca ratios show a very weak positive relationship with [B(OH)_4^-] and the dissolved carbonate species at the apparent calcification depth of P.obliquiloculata. The boron partition coefficients(K_D) between P. obliquiloculata B/Ca and seawater[B(OH)_4^-]/[HCO_3^-] distribute around 1.1×10^(-3)-1.3×10^(-3) with a mean value of(1.19±0.12)×10^(-3),and are significantly related to the nutrient concentration, especially phosphate. The lack of any clear correlation between the P. obliquiloculata B/Ca and seawater carbonate chemical parameters suggests that the physiochemical controls on boron incorporation are masked by the complexity of natural seawater condition. But the significant dependence of Ku on nutrient may likely be explained by a nutrient related growth-rate effect. Cd/Ca of P.obliquiloculata shows significant correlation with seawater phosphate concentration, and its partition coefficients(D_(cd)) are significantly related to temperature. A first-principle methodology of P. obliquiloculata B/Ca is applied;with the aid of Cd/Ca as a phosphate proxy and a constraint on K_D, to estimating sea water carbonate chemistry(e.g., pH). The results are fairly promising and allow us to propose the possibility to apply the combination of B/Ca and Cd/Ca proxies(and also Mg/Ca and δ^(18)O for estimating temperature and salinity) for the paleoreconstruction of seawater carbonate chemistry.
文摘【目的】探明不同pH条件下Ca/Cd化学计量比对辣椒根系Cd吸收动态特征的影响,为提升辣椒的耐镉能力及降低产品镉污染风险提供理论依据。【方法】以香辣四号线椒种子为研究对象,采用水培法模拟不同pH土壤溶液(pH 5、pH 6、pH 7),设置不同Ca/Cd化学计量关系(Cd+2 mM Ca、Cd+4 mM Ca、Cd+8 mM Ca、Cd+16 mM Ca、Cd+32 mM Ca),测定辣椒根系镉蓄积量、吸附量及吸收通量,研究不同pH条件下Ca^(2+)、Cd^(2+)交互作用对根系Cd吸收动态的影响。【结果】不同pH处理Cd蓄积量随Ca浓度增加而逐渐降低。pH 6条件下,Ca^(2+)对Cd^(2+)的竞争吸附影响最小,Cd蓄积量整体最高。pH 5条件下,竞争影响最大,Cd蓄积量整体最低,但根系表面Cd吸附量显著高于其他两个pH处理组。Ca/Cd化学计量比与单位面积根表Cd^(2+)的络合通量及吸收通量均呈负线性关系,单位面积根表Cd^(2+)络合量与吸收通量呈较好的正相关性,单位面积根表Cd^(2+)络合量对吸收通量的影响在pH 6时显著,Cd^(2+)的生物有效性更高,更易富集到植物体内。【结论】通过优化根际Ca/Cd化学计量比并维持弱酸性环境(pH 5),可最大限度抑制辣椒对Cd^(2+)的吸收,为安全生产低镉辣椒的农业实践提供技术参考。
