不同施肥处理对铅镉污染土壤中香椿品质的影响

本试验主要研究不同施肥处理对铅镉污染土壤中香椿品质的影响,为进一步探讨无公害蔬菜的栽培技术提供理论依据。以木本蔬菜香椿[Toona sinensis (A. Juss.) Roem.]为试材,以重金属铅镉复合污染土壤及背景土壤为栽培基质,进行了不施肥(CK)、单施无机肥(NPK)、单施有机肥(WM)及有机无机肥配施(1/2NPK+1/2WM)对香椿营养品质和安全品质影响的研究。香椿在叶片掉落前采集其顶端嫩芽,采用常规方法测定叶片可溶性糖、可溶性蛋白含量、维C含量、微量元素矿物质、硝酸盐含量以及重金属含量。结果表明：重金属铅镉污染基质下NPK、WM、1/2NPK+1/2WM处理可溶性蛋白含量分别为4.28、4.59、5.40 mg/g,均高于CK的3.56 mg/g且差异显著(P＜0.05);背景土壤基质下4种施肥处理可溶性蛋白含量分别为3.23、4.62、5.38、5.85 mg/g,均差异显著(P＜0.05)。重金属铅镉污染基质下3种施肥处理Vc含量依次是83.36、117.57、112.33 mg/100 g,均显著高于CK (P＜0.05);背景土壤基质下4种施肥处理的香椿叶片中的Vc含量依次为51.33、56.06、74.03、65.03 mg/100 g,WM和1/2NPK+1/2WM处理均显著高于CK (P＜0.05)。不管是在背景土壤或是在重金属铅镉污染土壤中,WM或1/2NPK+1/2WM处理均能显著提高香椿叶片中的可溶性糖含量和全Fe、全Mn的含量(P＜0.05),单施虫粪同时也能显著提高香椿叶片中全Cu、全Zn含量(P＜0.05)。在两种不同的栽培基质中,香椿叶片的Pb含量均表现为CK最低,其他处理均显著高于CK (P＜0.05),Cd含量则是NPK处理最低。该试验可得出以下结论：在2种栽培基质中,1/2NPK+1/2WM处理均能显著提高香椿叶片中可溶性蛋白质、维生素C、可溶性糖含量、有益微量元素矿物质含量等营养品质指标,并能在一定程度上降低硝酸盐和重金属铅镉含量,从而有效提高香椿品质。相同施肥处理下,重金属铅镉污染基质下的香椿叶片可溶性蛋白、可溶性糖含量、全Fe、全Mn、全Cu元素含量要比背景土壤中生长的低得多,但维生素C含量、全Zn含量和硝酸盐含量却是重金属污染基质中的香椿叶片高,说明重金属污染会明显降低香椿的品质。     

鄂东茯苓中重金属离子铜、镉含量的测定

采用了湿法消解、火焰原子吸收光谱法测定了鄂东英山、罗田两县的茯苓中铜、镉元素含量,并研究了煎煮后铜、镉两元素的含量变化。结果表明,当湿法消解用酸为浓硝酸和高氯酸体积比为4∶1时样品消化完全;英山县和罗田县茯苓中铜元素含量分别为3.27、2.25 mg/kg,其含量均未超过国家标准,但镉元素在英山县和罗田县茯苓中含量分别为3.62、3.72 mg/kg,均超过了国家标准。茯苓煎煮后英山县和罗田县的茯苓残渣中铜元素含量为0.98、0.67 mg/kg;镉元素的含量为2.24、2.32 mg/kg。通过煎煮后铜、镉元素部分溶入煎煮液中,溶出率分别为71%和38%。     

Prolonged summer droughts retard soil N processing and stabilization in organo-mineral fractions

Prolonged summer droughts are projected to occur as a consequence of climate change in Central Europe. The resulting reduced soil water availability may lead to alterations in rates of soil processes such as nitrogen partitioning among soil organic matter fractions and stabilization within soil. To study the effect of climate change-induced drought on (1) the distribution of nitrogen among soil organic matter fractions and (2) nitrogen stabilization, we performed a space-for-time climate change experiment. We transferred intact plant–soil–microbe mesocosms of a Rendzic Leptosol with a young beech tree from a slope with northwestern exposure in southern Germany characterized by a cool-moist microclimate across a narrow valley to a slope with southwestern exposure with a warm-dry microclimate, which reflects projected future climatic conditions. A control transfer was also done on the northwest-facing slope within the same area of origin. We combined a homogenous ¹⁵N labeling approach using ammonium nitrate with a physical fractionation procedure and chemical soil extraction protocols. Our aim was to follow the partitioning of ¹⁵N in different soil organic matter fractions, i.e. light fractions, organo-mineral fractions, and extractable soil fractions including microbial biomass, ammonium, nitrate, and dissolved organic nitrogen. Within less than one growing season, we observed a modified partitioning of recently applied inorganic ¹⁵N between different soil fractions in relation to drier summer conditions, with attenuated nitrogen turnover under drought and consequently significantly higher ¹⁵N concentrations in the relatively labile light fractions. We ascribed this effect to a decelerated mineralization immobilization turnover. We conclude that prolonged summer droughts may alter the stabilization dynamics because the induced inactivity of microorganisms may reduce the transfer of nitrogen to stabilization pathways. A retarded stabilization in organo-mineral associations enhances the risk of nitrogen losses during extreme rainfall events, which are projected to increase in the 21st century predicted by future climate change scenarios for Central Europe.     

Creation of Technosols to Decrease Metal Availability in Pyritic Tailings with Addition of Biochar and Marble Waste

Creation of Technosols with the use of different materials is a sustainable strategy to reclaim mine tailings and reduce metal mobility. For this purpose, a short‐term incubation experiment was designed with biochars derived from pig manure, crop residues and municipal solid waste added to tailings alone or in combination with marble waste. We aimed to assess the efficiency of the different amendments to decrease Cd, Pb and Zn availability in the Technosols and the fractions where metals were retained. Results showed that all amendments reduced metal mobility, directly related to increases in pH. Those materials with higher content of carbonates were more effective to immobilize metals (~99%). Municipal solid waste was highly effective to decrease metal mobility owing to the higher carbonate content, but addition of marble waste was needed to enhance metal immobilization with pig manure and crop residue. Decreases in Cd mobility were related to retention by the carbonate, Mn/Fe oxides and oxidizable (organic compounds) fractions. Decreases in Pb mobility were related to retention in the Mn/Fe oxides and residual fractions, while decreases in Zn mobility were related to retention in Mn/Fe oxides and oxidizable fractions. Association of Zn and Pb with the oxidizable fraction was also related to the recalcitrance of the organic compounds and so dependent on biochar type. Scanning electron microscopy coupled with energy dispersive X‐ray showed that biochar showed great affinity to interact with iron oxides, calcium sulfates and phyllosilicates. Copyright © 2017 John Wiley & Sons, Ltd.     

基于日本“痛痛病”的环境反思

指出了重金属污染现象在中国日益严重，其中也包括镉污染在内，而“痛痛病”是由慢性镉中毒引发的最典型的疾病，通过对“痛痛病”的全面研究，有益于人们在前人的基础上，对当今社会的镉污染事件进行反思。在文献综述的基础上对“痛痛病”的起因、经过、处理的结果，以及日本政府所采取的措施，进行了详细的介绍与分析。     

Genetic Variance in Cadmium Tolerance and Accumulation in Wheat Materials Differing in Ploidy and Genome at Seedling Stage

Cadmium (Cd) tolerance and accumulation in wheat varieties differing in ploidy and genome were investigated at seedling stage under controlled environmental conditions. The wheat varieties included six diploid, eight tetraploid, seven hexaploid and three octoploid species together with wheat relatives containing different genomes. Parameters of growth and photosynthesis were measured and the ratio of a given parameter under Cd treatment to that of the control was referred to as the Cd‐tolerant index of this parameter. Cd concentrations in shoots and roots, Cd accumulation in shoots (SCA) and Cd translocation (ratio of SCA to total Cd accumulation in plants) of the wheat varieties differing in ploidies generally decreased from octoploid to diploid, except for material containing the CCUU genome. It was found that Cd tolerance of these 24 wheat varieties varied with different ploidy and genomes at seedling stage. B and D genomes played a positive role, whereas the R genome played a negative role in Cd tolerance. By contrast, there were no significant differences between ploidies in Cd tolerance based on the observed growth and photosynthesis parameters. Using principal components analysis and cluster analysis, Triticum boeoticum Boiss was found to be the most Cd‐tolerant variety exhibiting low Cd translocation rates, whereas T. aestivum cv. Huixianhong and Jinghui 1 were identified as the most Cd‐sensitive varieties showing also higher Cd translocation rates.     

有机和无机氮对东南景天生长和镉积累的影响比较

通过水培试验,研究了有机和无机形态氮对两种生态型东南景天生长和镉积累的影响.结果表明,无论在低镉(10μmol·L-1)还是高镉(100 μmol·-1)条件下,与对照(T1)相比,外加无机形态氮(尿素)均能显著提高两种生态型东南景天地上部的生物量和叶绿素含量(P＜0.05);在低镉条件下,外加无机形态氮只能显著提高超积累生态型东南景天地上部镉积累量和非超积累生态型东南景天根部镉积累量(P＜0.05),在高镉条件下,外加无机形态氮对两种生态型东南景天体内镉积累量没有显著影响(P＞0.05).而无论在低镉还是高镉条件下,与对照(T1)相比,外加有机形态氮(精氨酸)能显著降低超积累生态型东南景天根系的生物量和叶绿素含量(P＜0.05);在低镉条件下,外加有机形态氮能显著提高两种生态型东南景天体内镉含量(P＜0.05),在高镉条件下,外加有机形态氮对两种生态型东南景天体内镉含量没有显著影响(P＞0.05).     

硬田头菇菌丝体对镉、铅及其复合污染的生长与富集响应

在PDA平板培养条件下,研究镉、铅及其复合污染对硬田头菇菌丝体生长的影响以及硬田头菇菌丝体对生长基质中镉、铅的生物富集作用.结果表明,在试验设置浓度范围内,菌丝生长势、菌落直径和菌丝体干重等均随着重金属浓度的增大而减弱(小)或降低.硬田头菇菌丝体对Cd、Pb均具有生物富集作用,并且随着重金属浓度的增大菌丝体中重金属含量逐渐增加.初步认为Cd、Pb复合污染促进菌丝体对Pb的吸收而抑制对Cd的吸收.     

镉胁迫对蒙山茶树生长及叶片生理指标的影响

通过盆栽试验,研究不同镉浓度对蒙山茶树生长及叶片生理特性的影响。结果表明:低浓度镉对茶树无明显毒害作用,当镉浓度达到60 mg/kg时,茶树植株受毒害基本死亡;春茶叶绿素含量加镉处理大多高于对照,其增加量先高后低;夏茶叶绿素总量随镉浓度的增加极显著降低,叶绿素含量与添加镉的量呈显著负相关,其相关系数r=-0.997;春茶、夏茶的丙二醛(Malondialdehyde,MDA)含量随镉处理浓度增加显著增加,其正相关系数分别为r=0.970,r=0.994(P<0.01);春茶游离脯氨酸含量随添加镉浓度的增加显著增加,相关系数r=0.829(P<0.05),夏茶游离脯氨酸在镉试验浓度下极显著增加,其相关系数r=0.980(P<0.01),且夏茶游离脯氨酸含量明显高于春茶;春茶可溶性糖都高于对照,其增加量先高后低.,相关系数为r=-0.342;夏茶可溶性糖呈下降趋势,其相关系数r=-0.909(P<0.05)。     

根瘤菌存在下土壤胶体和矿物对镉的吸附

Experiments were conducted to study the adsorption of Cd on two soil collids(red soil and yellowbrown soil) and three variable-charge minerals (goethite,noncrystalline Fe oxide and kaolin) in the absence and presence of rhizobia.The tested strain Rhizobium fredii C6,tolerant to 0.8 mmol L^-1 Cd,was selected from 30 rhizobial strains.Results showed that the isotherms for the adsorption of Cd by examined soil colloids and minerals in the presence of rhizobia could be described by Langmuir equation.Within the range of the numbers of rhizobial cells studied,the amount of Cd adsorbed by each system increased with increasing rhizobial cells,Greater increases for the adsorption of Cd were found in red soil and kaolin systems.Rhizobia influence on the adsorption of Cd by examined soil colloids and minerals was different from that on the adsorption of Cu.The presence of rhizobia increased the adsorption affinity of soil colloids and minerals for Cd,particularly for the goethite and kaolin systems.The discrepancies in the influence of rhizobia on the adsorbability and affinity of selected soil colloids and minerals for Cd suggesed the different interactions of rhizobia with various soil components.It is assumed that bacterial biomass plays an important role in controlling the mobility and bioavailability of Cd in soils with kaolinite and goethite as the major colloidal compnents,such as in variable-charge soil.