Enhancement of sulfide auto-oxidation by metal ion in artificial seawater and a seawater which is a possible source of aoshio

SUMMARY: Aoshio is hypoxic milky blue-green seawater observed in some eutrophic bays. Previous studies have shown that colloidal sulfur causes the coloration and that the source of aoshio water is attributed to coastal anoxic bottom water. Occurrences of aoshio have been reported in limited areas of coastal seawater, although hypoxic transparent water seems rather universal. Promotion in auto-oxidation of sulfide by metal ions in seawater was investigated to explain the occurrences of aoshio. Artificial seawater containing 10 μM metal ion was assayed for the sulfide oxidation rate. The velocity constant which represents the oxidation rate within the initial 30 min and the amount of reacted sulfide in 2 h were determined by oxygen monitoring and sulfide quantification, respectively. Fe²⁺ and Cu²⁺ enhanced the initial 30 min reaction. Fe²⁺, Fe³⁺ and Ni²⁺ increased the amount of reacted sulfide in 2 h, forming whitish turbid water. Seawater from a suspected source of aoshio water was also assayed for the auto-oxidation rate of sulfide. The oxidation rate in water from 12 m depth was 13–19 times higher than the artificial seawater without an addition of heavy metal ions. More than 15% of the oxidation rate in 12 m deep seawater was explained by dissolved iron in the seawater.     

The Effect of Lead and Zinc on Plant Growth and Chlorophyll Content of Holcus lanatus L.

Root length of Holcus lanatus L. declined rapidly with increasing lead and zinc concentrations in nutrient solution. In all used Pb and Zn concentrations root growth of genotypes coming from a Pb-Zn mine area, was greater than that of the control, suggesting that these genotypes evolved tolerance to Pb and Zn.
Negative correlation was also observed between chlorophyll content and increased heavy metal concentrations. The greater chlorophyll content found in tolerant genotypes, in different Pb and Zn concentrations, in comparison with the control, could be served to distinguish tolerant and non-tolerant genotypes.     

某些阳离子在大豆胞囊线虫生防系统中的作用

室内测定了不同浓度的 6种阳离子 :钼、硼、锌、铜、锰和铁对大豆胞囊线虫卵的孵化、大豆种子发芽和根系生长 ,以及对线虫生防菌———厚垣轮枝菌菌丝生长的影响。结果发现 ,在供试所有浓度下 ,铜、锰和铁明显抑制大豆胞囊线虫的卵孵化 ,锌具明显刺激作用 ;在供试浓度水平较低时 ,铜、锰和铁对大豆种子发芽及根系生长有轻微抑制 ,锰的抑制较为明显 ,但均不影响进一步发育 ;在供试浓度较低时 ,铜、锰和铁对厚垣轮枝菌菌丝生长无任何影响。铜可作为线虫生防制剂的添加剂。     

垃圾堆放场主要杂草对重金属的富集特点

通过测定重庆江北祺龙垃圾场、北碚金刚碑垃圾场、九龙坡二郎垃圾场中6种植物中4种重金属（Cd、Cu、Zn、Pb）的含量,发现灯笼草和鹅儿肠对4种重金属的吸收和富集能力较强,杂草对重金属的富集能力与土壤中重金属的背景值有一定的相关性。     

甘蔗热带种金属硫蛋白家族基因的克隆及响应重金属胁迫的表达分析

金属硫蛋白是一类富含巯基的低分子量蛋白,在植物的重金属解毒及细胞氧化还原调控等方面起重要的作用。本研究以甘蔗热带种Badila组培苗为材料,分别测定了其在CdCl2、ZnSO4和CuCl2水溶液培养条件下地上部和地下部的重金属含量,结果显示其对上述3种重金属有较强的耐受与富集能力。继而克隆了ScMT1(登录号为KJ504373)、ScMT2-1-5 (登录号为MH191346)和ScMT3 (登录号为KJ5043704) 3个金属硫蛋白家族基因,它们分别属于植物MT亚家族中的MT1、MT2和MT3型基因。ScMT1含有1个内含子和2个外显子,开放阅读框(Open Reading Frame, ORF)长228 bp,编码75个氨基酸; ScMT2-1-5含有2个内含子和3个外显子, ORF长246 bp,编码81个氨基酸; ScMT3含有1个内含子和2个外显子, ORF长198 bp,编码65个氨基酸。RT-qPCR显示, Cd2+胁迫下,在甘蔗地上部和地下部, ScMT2-1-5均连续显著上调表达,而ScMT1的上调应答出现延迟。ScMT3在地上部的上调应答出现延迟,在地下部呈"扬–...     

小白菜在不同生长阶段对重金属Cd的敏感性研究

通过小白菜盆栽试验,将小白菜的生长期分3个阶段,每个阶段10d,在不同生长阶段分别用含有Cd离子的水进行灌溉,并以清水作对照,研究分析了不同生长阶段重金属镉对小白菜的叶绿素含量的影响,对根系和茎叶干物质积累量的影响,以及对根系和茎叶中重金属Cd累积与分布的影响,表明小白菜生长的中后期不宜用含有Cd离子的污废水进行灌溉。     

香蕉对砷镉铅的富集转运特征及土壤重金属安全阈值

建立土壤重金属安全阈值是保障我国农产品质量安全的一道重要屏障.本研究通过盆栽模拟实验研究香蕉对砷(As)、镉(Cd)、铅(Pb)3种重金属的富集转运特点,进一步通过建立香蕉茎叶与土壤As、Cd、Pb总量和有效态含量的关系,推导香蕉种植系统的土壤As、Cd、Pb的安全阈值.结果显示,Cd、Pb对香蕉生物量表现出"低促高抑...     

农药和重金属复合污染物对大型溞的毒性效应

农药和重金属作为水环境中两类常见的污染物,其复合污染已经对水体生态和人类生存环境构成严重威胁。作者研究了3种常用农药（毒死蜱、三唑磷、氟虫腈）及2种常见重金属（铅、镉）对大型溞的急性毒性,同时采用五因素五水平二次通用旋转组合设计方案,研究了复合污染物体系对大型溞的联合毒性效应。结果表明:毒死蜱、三唑磷、氟虫腈、铅离子和镉离子对大型溞的48 h-EC50值分别为6.30、7.27、2.17、454.97和1 175.74 μg/L;5种污染物对大型溞的毒性效应贡献值依次为镉离子 > 三唑磷 > 氟虫腈 > 毒死蜱 > 铅离子;复合污染物对大型溞的毒性呈现出一定的相加效应;当水中毒死蜱质量浓度为0.81 μg/L、三唑磷为17.22 μg/L、氟虫腈为5.65 μg/L、铅离子为83.75 μg/L、镉离子为3 793.15 μg/L时,复合污染物毒性的理论协同效应最大。研究结果可为复合污染物风险评估提供参考。     

大型真菌重金属富集的研究进展

大型真菌是一类重要的生物资源,在自然界物质循环和维持生态平衡中发挥着非常重要的作用。自从大型真菌富集重金属的富集特性被发现以来,国内外的相关研究陆续展开。从大型真菌的重金属富集作用和重金属超积累作用、大型真菌富集重金属的生理生化机制及大型真菌重金属富集特性的应用等方面,总结、评述了大型真菌重金属富集方面的研究进展。