Metal interactions in bush bean plants grown in a glasshouse in amended serpentine soils from California

Abstract

Bush beans (Phaseolus vulgaris L. C.V. Improved Tendergreen) were grown with amendments in a glasshouse in two different serpentine soils from California. These serpentine soils are not high in Ni and Cr as in other areas of the world and the purpose of the study was to define the reasons for low plant yields in these two soils. The two soils behaved very differently. One seemed to have simple P deficiency and a mild imbalance of Ca‐Mg. The other soil appeared to have a severe Ca deficiency, the correction of which tended to increase Mg uptake also, but with improved yields. Present also seemed to be Zn, Cu, Al, Ni toxicities even though the levels of each were not high by leaf analysis tests. Stepwise regression for plants from one of the soils indicated that Cu concentration in leaves accounted for 60% of the yield variation (negative correlation), that Ca accounted for 9% more of it, and that P accounted for 13% more for a total of 82%. In the presence of low levels of Ca, some, at least, of the trace metals were toxic and Cu was one.     

Effect of High Nickel and Chromium Background Levels in Serpentine Soil on Their Accumulation in Organs of a Perennial Plant

The effect of high concentrations of nickel (Ni) and chromium (Cr) in alkaline serpentine Fluvisol (FL 1) on their uptake by grapevine as a perennial plant was compared to their accumulation on alkaline Fluvisol (FL 2) and an acid Cambisol (CM). The FL 1 revealed high pseudo total Ni (900–1737 mg kg^?1) and Cr (263–775 mg kg^?1) concentrations, whereas those in FL 2 and CM were low. Diethylenetriaminepentaacetic acid (DTPA)–extractable Ni was greatest in FL 1; DTPA‐extractable Cr was less than the detection limit. Concentrations of metals in grapevines revealed the pattern root > leaves > shoots > grapes. At FL 1, high Ni and Cr concentrations (40.7–68.8; 23.3–41.3 mg kg^?1) in roots were measured. In grapes, these concentrations were low (Ni 0.4–0.9; Cr 0.1–0.6 mg kg^?1), whereas those on FL 1 do not differ significantly from others, indicating that alkaline serpentine soils may be used for grapevine or other perennial plant growth.     

Comparison of Low-Molecular-Weight Organic Acids and Ethylenediaminetetraacetic Acid to Enhance Phytoextraction of Heavy Metals by Maize

We compared acetic, ascorbic, and oxalic acids with ethylenediaminetetraacetic acid (EDTA) to enhance phytoextraction of nickel (Ni), manganese (Mn), zinc (Zn), copper (Cu), cadmium (Cd), and lead (Pb) by maize. Except ascorbic acid, acids significantly (P < 0.05) decreased shoot dry weight with maximum (5.60 g pot^?1) recorded with ascorbic acid and minimum with oxalic acid (4.06 g pot^?1). Maximum ammonium bicarbonate–diethylenetriaminepenta acetic acid (AB-DTPA)–extractable nickel (19.94 mg kg^?1) was recorded with EDTA and it was minimum (10.57 mg kg^?1) with oxalic acid. The EDTA significantly (P < 0.05) increased AB-DTPA-extractable lead while other acids decreased it. Except acetic acid, other acids significantly (P < 0.05) increased Ni and Zn concentration in shoots with maximum Ni (9.22 mg kg^?1) and Zn (37.40 mg kg^?1) with EDTA.     

钙对大豆幼苗镍毒害的缓解效应及对抗氧化酶活性的影响

采用盆栽方法,研究了镍毒害条件下外源钙对大豆镍毒害的缓解效应以及对其叶片组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)活性的影响,以探讨钙缓解植物镍毒性的生理机制.研究结果表明:Ni2+60 mg/kg添加量对大豆幼苗生长表现出明显的抑制作用,但是当加入不同钙量后,大豆的镍毒害症状得到不同程度的缓解,Ca2+ 200 mg/kg处理的缓解作用好于Ca2+ 100 mg/kg.与不施镍处理相比,单施Ni2 60 mg/kg处理的大豆叶片组织SOD、CAT和APX活性明显下降,而POD活性明显上升.当配施Ca2以后,大豆叶片组织中SOD、CAT、POD和APX活性明显提高,且Ca2+ 200 mg/kg处理的上升程度比Ca2+ 100 mg/kg处理的大.因此,Ca2+是通过提高叶片组织抗氧化酶活性,增强活性氧清除能力,而使大豆的镍中毒症状得到缓解,这是Ca2+减轻大豆镍毒害的生理机制之一.     

土壤中镍生态阈值的影响因素及预测模型

利用实验室获得的毒理学数据建立土壤生态阈值需通过老化-淋洗因子校正以消除外源添加的人工污染与野外实际污染的差异。该文利用基于中国土壤的17个物种的镍毒理学数据建立镍土壤生态阈值并利用老化-淋洗因子对数据进行校正。结果表明淋洗效应在pH值大于8.5的土壤中尤为显著,除个别土壤外,淋洗因子(LF)值均大于2;老化效应在碱性土壤(pH值>7.0)中更为显著,且老化因子(AF)值随着土壤pH值的升高而增大。pH值、有机碳含量(OC)、阳离子交换量(CEC)可分别控制镍生态阈值变异的86.2%、9.0%和4.1%。土壤pH值是影响土壤镍生态阈值的最重要因子,基于土壤pH值和OC的2因子预测模型能较好地预测土壤镍生态阈值,其相关性达到95.2%,利用该研究获得的两因子模型并依据土壤性质参数可预测不同类型土壤中的镍生态阈值。     

福建铁观音茶园土壤中的镍及其向茶叶的转移

对福建省安溪县、华安县、永春县主要铁观音茶生产乡镇的茶园表层土壤和相应茶叶中的镍含量状况进行了调查.结果表明:茶园土壤全镍含量为4.08-123.44 mg.kg-1,平均值19.06 mg.kg-1,绝大部分土壤未受到明显的镍污染,土壤全镍含量与有机质和粘粒含量均呈极显著正相关;土壤有效镍含量为0.12-4.84 mg.kg-1,平均值0.74 mg.kg-1,与土壤阳离子交换量(CEC)和有机质含量呈显著正相关;茶叶镍含量为(3.70±1.52)mg.kg-1.茶叶对镍的吸收富集能力随着土壤镍含量的升高而降低.     

Ni/TiO_2-Al_2O_3催化剂的制备及其在松节油催化加氢反应中的应用

以溶胶凝胶法制备Ti O_2-Al_2O_3复合载体,采用超声波辅助浸渍负载Ni制得Ni/Ti O_2-Al_2O_3催化剂,将其应用于松节油催化加氢反应,考察了催化剂制备条件及松节油催化加氢反应条件对催化加氢的影响。结果表明,复合载体中钛铝物质的量之比(钛铝比)值0.4、载体焙烧温度550℃、超声波功率280 W、硝酸镍浸渍液浓度0.5 mol/L和超声波辅助浸渍时间2 h的条件下,制备的催化剂Ni/Ti O_2-Al_2O_3催化性能最高。最佳的加氢反应条件为:反应时间140 min、反应压力4.5 MPa、反应温度150℃和催化剂用量为松节油质量的5%,该条件下原料中α-蒎烯转化率达97.27%,产物顺式蒎烷的选择性为96.15%,顺式蒎烷的得率为93.52%。     

吉林省镍矿区土壤重金属Cu、Ni、Pb、Zn的形态分布特征及活性

为了正确评价吉林省镍矿区耕地土壤重金属Cu、Ni、Pb、Zn的潜在环境效应,采集了吉林省镍矿区11个有代表性的耕层土壤样品,测定了土壤p H、有机质含量和重金属全量,同时采用Tessier连续提取法对土壤重金属进行了形态分析,采用DTPA提取了土壤重金属的生物有效态,探讨了吉林省镍矿区土壤重金属的形态分布规律和活性及其与土壤性质的关系。结果表明:吉林省镍矿区土壤重金属Cu、Ni、Pb、Zn的形态规律略有差异,但均以残留态为主要形态,可交换态或碳酸盐结合态所占比例最小;Cu、Ni、Pb、Zn的DTPA可提取态含量分别为1.21~8.48,0.03~25.92,0.08~2.66,1.42~4.76 mg/kg,平均值分别为3.90,8.24,0.53,2.98 mg/kg;土壤Cu、Ni、Pb、Zn的DTPA可提取率分别为2.41%~14.61%,0.16%~34.53%,0.32%~4.93%,1.60%~5.27%,平均值分别为7.89%、9.56%、1.70%、3.23%,不同采样点土壤重金属的DTPA可提取量和可提取率均有很大差异。对于吉林省镍矿区土壤Cu、Ni、Pb、Zn 4种重金属,Ni的活性和生物有效性最高,Pb的活性和生物有效性最低;在土壤p H、有机质含量和土壤重金属全量3个因素中,土壤重金属全量是影响吉林省镍矿区土壤Cu、Ni、Pb、Zn的形态分布和DTPA可提取态的主要因素。     

Silicon alleviates nickel toxicity in cotton seedlings through enhancing growth,photosynthesis, and suppressing Ni uptake and oxidative stress

Cotton (Gossypium hirsutum L.) is a well-known and economically most beneficial crop worldwide while nickel (Ni) toxicity is a widespread problem in crops grown on Ni-contaminated soils. We investigated the response of silicon (Si) in cotton under Ni stress with respect to growth, biomass, gas exchange attributes, enzymatic activities, and Ni uptake and accumulation. For this, plants were grown in hydroponics for 12 weeks with three levels of Ni (0, 50, and 100 µM) in the presence or absence of 1 mM Si. Results showed that Ni significantly reduced the plant growth, biomass, gas exchange attributes, and pigment contents while Si application mitigated these adverse effects under Ni stress. Nickel stress significantly decreased antioxidant enzymes’ activities while increased malondialdehyde (MDA), hydrogen peroxide (H₂O₂), and electrolyte leakage (EC) in leaves and roots. The application of Si enhanced the activities of antioxidant enzymes and reduced MDA, H₂O₂, and EC in plants. Nickel application significantly increased Ni concentration and accumulation in leaf, stem, and roots while Si application significantly decreased Ni in these plant parts. The present study indicates that Si could improve cotton growth under Ni stress by lowering Ni uptake and reactive oxygen species (ROS) and by increasing antioxidant enzymes activities.     

基于DGT技术分析土壤重金属Cd、Ni的老化特征

为明确重金属在土壤中的老化进程,锁定关键影响因子,采用梯度扩散薄膜(DGT)技术探究了外源添加Cd和Ni两种重金属在6种不同类型土壤中的老化特性,并探讨了影响重金属老化过程的关键因子。结果表明:Cd、Ni在不同土壤中的老化过程差异性明显,Ni比Cd更易老化。进入土壤中的重金属老化过程大致分为3个阶段,添加后20～30 d为快速老化阶段,30～60 d为缓慢老化期,除个别高污染土壤外,其余土壤均在60 d后基本达到平衡。数据分析结果表明,6种土壤中Cd、Ni的老化平衡浓度由初始浓度决定,初始浓度、CEC等因子为影响Cd、Ni老化速率的主控因素。DGT作为一种原位、非破坏性、不引入外源离子的监测技术,可以动态展示土壤外源添加重金属在老化过程中的活性变化,对评估土壤重金属污染风险具有重要参考价值。