Excess trace metal effects on cotton: 4. Chromium and lithium in Yolo loam soil

Abstract

Two cultivars of cotton (Gossypium spp) were grown in Yolo loam soil in a glasshouse to determine phytotoxicity effects of Cr and Li and possible interactions with other metals. The Cr at 100 μg/g soil had no adverse effects on either cultivar studied. A Cr increase was not observed in either stems or leaves. Both cultivars tolerated 25 and 50 μg Li/g soil. The 50 μg Li/g soil resulted in leaves of Acala SJ‐2 with 432 μg Li/g leaves and 720 in Giza 45. The 100 μg Li/g soil resulted in 74% and 87% leaf yield reductions in Acala SJ‐2 and Giza 45 respectively. Leaf concentrations of Li respectively were 1950 and 1850 μg/g. Except at the highest level of Li, leaves had higher concentrations of Li than did roots. The Cr and Li resulted in some plant metal interactions.     

微波消解-FAAS测定番木瓜不同部位的金属元素含量

为探讨番木瓜果肉、果皮、瓜籽中金属元素的含量,采用微波消解-FAAS法测定了番木瓜3个部位的K、Na、Ca、Mg、Cu、Fe、Zn共7种金属元素的含量,并对微波消解条件进行了优化。结果显示,在优化的微波消解条件下,样品消解完全、速度快、效果好,FAAS测定的各金属元素质量浓度与吸光度均呈良好的线性关系,相关系数r为0.995 7～0.999 9,检出限为0.002～0.131,回收率为98.30%～101.67%,RSD为0.20%～4.12%(n=6),说明测定方法可靠,结果稳定;番木瓜3个部位均含有较高的K、Ca、Mg,但Cu、Fe、Zn含量均较低,与番木瓜果肉相比,番木瓜果皮和瓜籽中K、Mg、Cu、Zn、Fe含量较高,食品和药品开发优势更突出。     

Significance of salt transport patterns in rice varieties differing in salt tolerance

Abstract

The absorption mechanisms for Na, K, SO₄ and Cl were tested in a salt tolerant (PVR 1) and a salt sensitive (GEB 24) rice varieties. The salt tolerant variety accumulated significantly larger amounts of Na than the salt sensitive variety. Further, PVR 1 absorbed SO₄ from Na₂SO₄ in preference to that from K₂SO₄. The absorption patterns for K and Cl were similar in both the varieties. It is concluded that the capacity of plant species to accumulate greater amounts of Na is a reflection of their halophytic feature.     

新牧一号苜蓿MvP5CS基因的克隆和功能分析

为研究苜蓿（Medicago sativa）耐盐分子机制，为抗逆分子育种提供依据，通过同源克隆和RT PCR技术克隆了新牧一号杂花苜蓿（M.varia Xinmu 1）的MvP5CS基因， MvP5CS全长2 148 bp，Genbank登录号为：EU371644。荧光定量PCR分析发现，在盐胁迫下MvP5CS基因表达明显上调，说明 MvP5CS与苜蓿的耐盐性相关。利用农杆菌介导的叶盘转化法，将MvP5CS基因成功转入烟草（Nicotiana tabacum），盐胁迫下转MvP5CS基因T1代烟草萌发率和根长均高于非转基因烟草。表明新牧一号苜蓿P5CS基因能够提高转基因烟草的耐盐性。     

生态环境中重金属的化学形态转化及影响因素研究

提出了环境中重金属的化学形态发生转化的2种途径,探讨了影响此转化过程的环境条件,包括pH、氧化还原电位和吸附质表面的键合作用等。     

Interaction of Cd-hyperaccumulator Solanum nigrum L. and functional endophyte Pseudomonas sp. Lk9 on soil heavy metals uptake

Bioaugmentation is a promising method for assisting phytoextraction of heavy metals from contaminated soil, and the development of bioaugmentation-assisted phytoextraction requires the understanding of the mechanism involved in the interaction between plants and inocula. In this study, a pot study was conducted to evaluate the effect of bacterial endophyte Pseudomonas sp. Lk9 which can produce biosurfactants, siderophores and organic acids on the growth and metal uptake of Cd-hyperaccumulator Solanum nigrum L. growing in multi-metal-contaminated soil. The results revealed that Lk9 inoculation could improve soil Fe and P mineral nutrition supplies, enhance soil heavy metal availability, and affect host-mediated low-molecular-weight organic acids secretion, thereby significantly increasing S. nigrum shoot dry biomass by 14% and the total of Cd by 46.6%, Zn by 16.4% and Cu by 16.0% accumulated in aerial parts, compared to those of non-inoculated control. The assessment of phytoextraction showed that Lk9 inoculation elevated the bioaccumulation factor of Cd (28.9%) and phytoextraction rates of all metals (17.4%, 48.6% and 104.6% for Cd, Zn and Cu, respectively), while the translocation factors had negligible difference between Lk9 inoculation (3.30, 0.50 and 0.40 for Cd, Zn and Cu, respectively) and non-inoculated control (2.95, 0.53 and 0.42 for Cd, Zn and Cu, respectively). It was also found that the symbiotic association between S. nigrum and Lk9 significantly increased the soil microbial biomass C by 39.2% and acid phosphatase activity by 28.6% compared to those in S. nigrum without Lk9. This study would provide a new insight into the bioaugmentation-assisted phytoextraction of heavy metal-contaminated soils.     

Response of ammonia oxidizing microbes to the stresses of arsenic and copper in two acidic alfisols

Soil pollution by elevated heavy metals exhibits adverse effects on soil microorganisms. Ammonia oxidizing bacteria and ammonia oxidizing archaea perform ammonia oxidative processes in acidic soils. However, influence of heavy metal stress on soil ammonia oxidizers distribution and diversity is inadequately addressed. This study investigated the responses of ammonia oxidizing bacteria and archaea to heavy metals, Cu and As during short-term laboratory experiment. Two different acidic alfisols named as Rayka and Hangzhou spiked with different concentrations of As, Cu and As + Cu were incubated for 10 weeks. Significant reduction in copy numbers of archaeal-16S rRNA, bacterial-16S rRNA and functional amoA genes was observed along elevated heavy metal concentrations. Ammonia oxidizing archaea was found to be more abundant than ammonia oxidizing bacteria in all the heavy metal treatments. The potential nitrification rate significantly decreased with increasing As and Cu concentrations in the two soils examined. Denaturing gradient gel electrophoresis analysis revealed no apparent community shift for ammonia oxidizing archaea even at higher concentrations of As and Cu. Phylogenetic analysis of archaeal amoA gene from 4 clone libraries indicated that all the archaeal amoA sequences were placed within 3 distinct clusters from soil and sediment group 1.1b of Thaumarchaeota. Our results could be useful for the better understanding of the ecological effects of heavy metals on the abundance and diversity of soil ammonia oxidizers.     

基于神经网络模型的青岛市城区土壤重金属污染源定位

建立基于遗传算法的BP神经网络系统,该模型可以有效描绘区域中重金属元素的分布情况,并由此通过各元素浓度极大值点求出污染源近似坐标,实现对污染源的定位.将该模型运用于青岛市,根据青岛市不同功能区的土壤重金属含量调查结果,实现了对可能重金属元素污染源位置的预测.     

浮顶油罐大修中金属结构的涂装

浮顶罐大修中，金属结构的涂装工作量大，强度高，制定合理的朋修方案，选择适用的表面预处理方式，编制细致的涂装工序，是提高油罐大修的工作效率和保证施工质量的有效措施。     

甘肃河西盐碱荒地开发对河流水质的影响

本文详尽分析了甘肃河西地区张掖临泽部分盐碱荒地开发对生态环境产生的主要污染参数、污染因子及污染物排放量，预测了洗盐废水中可溶性盐分对黑河水质的影响。