不同生境下锌镉在伴矿景天不同叶龄叶中的富集与分布特征

田间试验、温室盆栽和生长室水培试验研究了Zn和Cd超富集植物伴矿景天不同叶龄叶片的Zn、Cd富集和分布特征。结果显示,田间条件下伴矿景天新叶中Cd浓度高于成熟叶、但新叶中Zn浓度低于成熟叶。温室盆栽试验发现,连续种植伴矿景天,第4季时低污染土壤（S1）上新叶中Zn浓度低于成熟叶,但高污染土壤（S4）上新叶中Zn浓度高于成熟叶;而到了第6季,S1、S4上新叶中Zn浓度均低于成熟叶,且在S1上两者达到显著水平;第4和第6季,伴矿景天新叶中Cd浓度始终高于成熟叶（除S1成熟叶中Cd浓度略高于新叶外）。水培试验结果发现,无论在高Zn（600 mmol/L）、高Cd（100 mmol/L）,还是低Zn（10 mmol/L）、低Cd（1 mmol/L）处理,新叶中Zn、Cd浓度均高于成熟叶;而且随着处理时间的延长,新叶和成熟叶中Zn、Cd浓度均明显上升。水培条件下,新叶和成熟叶中Zn最高分别为43 107、33 774 mg/kg（以干重计）（600 mmol/L,处理56 天）;新叶和成熟叶中Cd的最高浓度分别为15 057、9 060 mg/kg（以干重计）（100 mmol/L Cd,处理56 天）。这些结果表明,Zn、Cd在伴矿景天新叶和成熟叶中富集和分布与其生长介质中Zn、Cd的浓度尤其是有效态浓度、处理时间及植物所处的生长阶段等有关,同时也表明Zn、Cd优先分布于新叶可能与伴矿景天超富集Zn、Cd的机制有关。     

铜对伴矿景天生长及锌镉吸收性的影响

利用植物生长室水培试验和温室土培盆栽试验相结合,研究了Cu对Zn、Cd超积累植物伴矿景天生长及Zn、Cd吸收性的影响。水培试验结果显示,0.31～50μmol/L Cu处理14天对伴矿景天生长及对Zn、Cd吸收性没有显著影响;但100μmol/L Cu处理显著抑制植物生长,降低地上部Zn、Cd及根中Cd浓度,对根中Zn浓度变化没有显著影响。盆栽试验结果发现,在土壤Cu仅为3.61 mg/kg时伴矿景天生长不良,外加Cu显著促进其生长并随Cu浓度升高效应增加;但施用3 mmol/kgEDDS和再次外加250 mg/kg Cu处理使伴矿景天因体内Cu积累量过高而导致明显毒害,地上部Cu最高达1 068 mg/kg。可见低量Cu处理可促进伴矿景天生长,利于植物对土壤Zn、Cd的吸取修复,但土壤中Cu浓度过高将抑制Zn、Cd超积累植物的生长,降低其Zn、Cd吸收能力,在利用该Zn、Cd超积累植物修复高Cu的Zn和Cd污染土壤时应采取适当措施降低Cu毒害效应。     

镉污染土壤伴矿景天的萃取强化-螯合剂和植物激素的叶面调控

为提高Cd超富集植物伴矿景天(Sedum plumbizicola)的植物萃取能力,采用盆栽试验研究螯合剂乙二胺四乙酸(EDTA)和植物激素脱落酸(ABA)单独和联合作用的叶面调控对伴矿景天生长和Cd吸收转运的影响,并通过大田试验进行验证。结果表明:盆栽试验叶面喷施EDTA、ABA均能提高伴矿景天对Cd的转运,地下部至地上部的Cd转运系数为EDTA＞ABA,但叶面EDTA处理对生长旺盛期伴矿景天的生长有抑制。伴矿景天各部位Cd富集浓度差异很大,呈现新叶＞地下部＞茎＞老叶,新叶中Cd浓度是老叶的3.6~5.4倍,且主要富集在细胞壁和细胞器中,占总富集量的88%~94%。EDTA处理新叶细胞器中Cd浓度剧增,ABA处理新叶细胞壁中Cd浓度增加,ABA和EDTA联合使用可以缓解EDTA对生长的抑制,且更有利于Cd从根系向地上部转运。大田小区试验叶面诱导强化伴矿景天Cd萃取是可行的,ABA和EDTA联合处理显著增加伴矿景天总Cd积累量,增幅达到37.87%。研究结果为伴矿景天修复Cd污染土壤提供理论指导。     

伴矿景天和鹅掌柴间作系统中根系相互作用对植物生长和镉锌吸收的影响

为明确不同物种根系间的相互作用对植物生长和重金属元素吸收的影响,以Cd、Zn超积累植物伴矿景天与花卉植物鹅掌柴为材料,研究二者根系相互作用及对植物生长和Cd、Zn的影响。结果发现,二者根系具有相互抑制生长的作用。单作条件下伴矿景天的Cd、Zn吸收量最高,分别达0.812、19.6 mg/盆;较单作相比,无分隔间作条件下伴矿景天对土壤Cd、Zn吸收降低分别达30.0%和30.6%。两种植物根系改变了土壤养分性质,对土壤钾和磷的利用分别具有竞争和互补作用,但其有效态含量并未降低到亏缺水平,养分竞争可能不是两种植物根系相互作用的主要因素。水培试验表明鹅掌柴根系分泌物对伴矿景天的生长和Cd吸收具有抑制作用。     

水分特征对伴矿景天生长和重金属吸收性的影响

利用盆栽试验研究了水分特征对伴矿景天生长和重金属吸收性的影响.结果表明:在70% 土壤最大田间持水量(70%WHC)处理下,伴矿景天生长最好,其地上部鲜重显著高于其他处理;70%WHC处理伴矿景天对重金属吸收能力最强,其茎中Zn的浓度显著高于其他处理,茎中Cd的浓度分别比35%WHC、100%WHC、淹水处理高27.1%、29.0%、63.1%;叶中的Zn浓度表现出与茎中相同趋势,叶中Cd的浓度与茎中不同,以100%WHC处理最高.70%WHC处理下,植物提取Zn、Cd的效率最高,其修复效率均显著高于其他处理.这些结果表明,土壤水分状况在土壤重金属污染伴矿景天植物吸取修复中起着重要作用.     

土壤紧实度对伴矿景天生长及镉锌吸收性的影响研究

采集黏土、壤黏土和砂质壤土,分别设置无压实、低紧实度及高紧实度3种处理,通过盆栽试验研究了土壤紧实度对Cd、Zn超积累植物伴矿景天生长和Cd、Zn吸收性的影响。结果表明,与无压实处理比较,砂质壤土、壤黏土和黏土中伴矿景天地上部生物量在低紧实度下显著下降66.8%~83.5%、59.9%~60.4%和57.9%~71.4%;高紧实度处理却显著提高了伴矿景天的根系活力(142%~241%)。高紧实度处理显著降低了壤黏土上伴矿景天地上部Cd和Zn含量,但低紧实度对砂质壤土和黏土上伴矿景天地上部Cd和Zn含量无显著影响。与无压实处理比较,低紧实度显著降低了砂质壤土、壤黏土和黏土上伴矿景天的Cd吸取量,分别下降50.4%~73.8%、61.4%~74.9%和43.4%~63.3%,Zn吸取量下降48.7%~79.5%、73.6%~79.0%和46.1%~63.5%;土壤紧实度对壤黏土上伴矿景天的镉锌吸取效率影响最明显。     

调控剂对锌镉污染土壤植物修复效率及后茬蔬菜重金属吸收的影响

采用盆栽试验,在连续12年高量施用污泥有机肥引起的Zn、Cd污染土壤上种植伴矿景天,并向土壤中添加亚氨基二琥珀酸(IDS)、乙二胺二琥珀酸三钠(EDDS)、硫磺等化学调控剂及稳定剂钙镁磷肥,研究调控剂对伴矿景天吸收Zn、Cd及施用钙镁磷肥对后茬蔬菜重金属污染风险的影响,以期探索出既可提高超积累植物重金属吸取修复效率又能降低后茬农作物重金属污染风险的植物修复模式.结果表明,施用120 mmol/kg硫粉(Sed+S)处理可显著增加伴矿景天地上部生物量,分别比未加调控剂的对照处理伴矿景天(Sed)、伴矿景天添加有机调控剂(Sed+OE)处理增加34.7％和47.9％.施用3 mmol/kg IDS则显著降低了伴矿景天地上部Cd浓度,比Sed处理降低了35.5％.施用钙镁磷肥稳定剂可有效降低后茬蔬菜苋菜体内Zn、Cd浓度,降幅为57％、63％,施用4 g/kg钙镁磷肥后土壤醋酸铵提取态Zn、Cd分别较对照降低66.1％、72.4％.可见,适当施用硫肥能促进伴矿景天的生长,添加钙镁磷肥降低土壤有效态重金属浓度,减少后茬作物污染风险.     

酸性土壤上伴矿景天铝毒的缓解技术研究

酸性土壤上易产生铝（Al）毒害作用，缓解Al毒对于污染土壤上超积累植物的生长及重金属有效削减具有重要意义。本研究比较了不同措施对镉（Cd）超积累植物伴矿景天的Al胁迫缓解作用，结果发现：① 在水培条件下，锌添加可促进了Al胁迫下伴矿景天根表Cd2+吸收速率，而添加氯化钙或柠檬酸没有显著的缓解作用；② 在盆栽试验条件下，添加石灰处理显著提高了土壤pH，促进了伴矿景天生长和地上部对Cd的吸收，但添加生物质炭或柠檬酸没有显著缓解Al毒对伴矿景天生长和Cd吸收的抑制，添加柠檬酸反而加剧了土壤酸化，提高了土壤Al的活性；③在伴矿景天与荞麦间作条件下，其一定程度上降低了土壤的Al活性，在合适的种植密度下并未显著影响伴矿景天单株地上部Cd吸收量。综上，酸性土壤上耐Al作物与修复植物间作、结合添加改良剂调控Al毒，能够不显著降低土壤Cd的有效性和修复植物的Cd吸收，进而实现污染土壤的边生产边修复。     

柠檬酸活化协同伴矿景天-玉米套作对镉轻微污染土壤的修复效果

伴矿景天-玉米套作是一种原位、绿色、边生产、边修复Cd污染土壤的有效方式,土壤中添加柠檬酸可有效提高伴矿景天的修复效率。该研究通过田间微区试验,探究了柠檬酸不同添加方式协同伴矿景天-玉米套作模式对Cd轻微污染稻田土壤修复机理及修复效果。结果表明：1）同一种植模式,添加柠檬酸可提高土壤Cd有效性,显著提高伴矿景天的修复效率;5次添加柠檬酸,伴矿景天单作时修复效率提高了2.09%,套作时提高了10.54%。2）柠檬酸添加量相同时,套种与伴矿景天单种相比,修复效率提高了3.42%～4.27%,同时减少了玉米对土壤Cd的吸收。3）5次添加柠檬酸协同伴矿景天-玉米套作,伴矿景天Cd移除量可达18.59 mg/m2,该处理伴矿景天对轻微Cd污染土壤的修复效果最佳。因此,柠檬酸协同伴矿景天-玉米套作的联合修复模式可强化伴矿景天修复效率,可运用于Cd轻微污染稻田土壤的修复,并可实现边修复边生产。     

植物吸取修复及钝化处理对后茬水稻镉吸收的影响

采集湖南湘潭县某地镉(Cd)污染酸性农田土壤及其经伴矿景天分别吸取修复两季和三季后的土壤,采用盆栽试验研究了经伴矿景天修复及钝化改良与否对土壤pH、有效态Cd、Zn以及水稻生长和稻米Cd、Zn浓度的影响。结果表明:未改良的处理,随着修复次数的增加,土壤pH显著降低,降低幅度为0.26~0.38个单位;且修复两季、三季土壤CaCl_2提取态Cd浓度较未修复土壤分别降低19.4%、24.0%;修复后土壤种植水稻品种W184,其糙米中Cd浓度显著降低,但依然超标;修复三季土壤种植低积累水稻品种IRA7190,其糙米中Cd由0.47 mg/kg降为0.03 mg/kg。施加钝化剂海泡石和石灰(10 g/kg+1 g/kg)后,修复两季、三季土壤的pH显著升高,较未施钝化剂处理土壤pH分别提高0.95、0.72;土壤CaCl_2提取态Cd浓度分别降低79.8%、79.5%;修复两季、三季土壤上水稻W184糙米的Cd浓度与未施加钝化剂相比,分别降低27.3%、44.4%,均降至国家食品安全限值0.2 mg/kg以下;无论是否添加钝化剂,伴矿景天吸取修复三季的土壤上水稻IRA7190糙米中Cd浓度均仅0.03 mg/kg。     

朝天委陵菜的重金属耐性与吸收性研究

利用植物生长室水培试验和温室土培盆栽试验的方法,研究了朝天委陵菜在不同浓度Pb水培条件下和Cu、Zn、Pb、Cd复合污染土壤条件下的重金属耐性和吸收性,结果表明,水培条件下随着处理浓度的增加,朝天委陵菜均生长良好,虽高浓度Pb处理下出现植株矮小、叶渐黄、根系变黑等毒害症状,但植株并未死亡,表明在水培条件下朝天委陵菜对Pb具有极强的耐性;在最高浓度3 600μmol/L Pb处理下地上部和根中Pb浓度达到最大值,分别为947 mg/kg和71 053 mg/kg。在温室土培盆栽条件下,朝天委陵菜在外加Cu、Zn、Pb和Cd分别为200、1 000、1 000和5 mg/kg的土壤上较对照生长受到抑制,地上部Cu、Zn、Pb和Cd浓度分别达到741±164、18 248±2 222、1 543±483和29.4±5.2 mg/kg;外加重金属更高时则导致植株死亡。朝天委陵菜对Pb胁迫和Cu、Zn、Pb、Cd复合污染土壤具有较强的耐受性,可作为重金属尤其是Pb污染土壤的修复植物。     

Cadmium Uptake and Distribution by Different Maize Genotypes in Maturing Stage

Abstract

A pot experiment was conducted to investigate the effects of different cadmium (Cd) concentrations of phaeozem on growth and uptake of Cd and mineral nutrient copper (Cu) and zinc (Zn) by three maize genotypes in the mature stage. The results showed that the dry‐matter accumulation of shoots was inhibited by added Cd for Jidan209 and Jitian6, but this did not influence Chunyou30. The root biomasses decreased significantly for Jitian6 and stimulated Jidan209 and Chunyou30. Yields of three genotypes of maize were decreased by increasing soil Cd concentrations. Among them, Chunyou30 had a high tolerance and Jitian6 was most sensitive to Cd. The accumulation order of Cd in different parts of plants was root > leaf > stem > grain. The percentage of absorbed Cd by roots was 70–85% of total absorbed amount. Cadmium uptake by maize in the mature stage had a significant genetic variation: Jitian6 > Jidan209 > Chunyou30 for root, stem and leaf, and Jidan209 > Jitian6 > Chunyou30 for grain, respectively. Increase of soil Cd had no significant effect on Zn concentration of leaves, but there was a significant genetic variation: Chunyou30 > Jidan209 > Jitian6 (P=0.023). Cu concentration of leaves was increased significantly with increase of soil Cd (P<0.01), but no genetic variation was observed.     

镉处理根表铁膜对水稻吸收镉锰铜锌的影响

本试验利用营养液和土壤培养系统,研究不同Fe、 Cd处理下根表铁膜对水稻吸收Cd、 Mn、 Cu、 Zn的影响。土壤中Fe的水平为0、 1、 2 g/kg Fe（以FeSO47H2O的形式供应）,Cd 的水平为0、 2、 10 mg/kg Cd（以3CdSO48H2O的形式供应）。营养液中Fe和Cd的水平分别为0、 10、 30、 50、 80、 100 mg/L Fe 和 0、 0.1、 1.0 mg/L Cd。收获后测定水稻根表、 根中和地上部Cd、 Fe、 Mn、 Cu、 Zn 含量。试验结果表明,两种培养方式下,随着介质中Fe浓度的增加,水稻根表铁膜（DCB-Fe）逐渐增多。土壤培养方式下,根表铁膜中Cd 和 Mn 含量随铁膜量增加而略有增加,所有元素含量均表现为根中大于铁膜中。营养液培养条件下,根表铁膜中Mn和Cu含量在高量 Fe 供应时有所增加, Mn、 Cu、 Zn表现为铁膜中大于根中。根表铁膜中Zn含量在两种培养方式下均未呈现一定规律性变化。根中和地上部 Cd、 Mn、 Cu、 Zn 含量一般都随介质中Fe浓度的增加而下降,Cu和Zn含量在加Cd处理中下降。以上结果证明,铁膜对Cd 的吸附阻挡能力有限,对Mn、 Cu、 Zn 的吸附作用因培养方式和元素种类不同而有所差异,植株体内微量元素含量的下降主要与它们之间的相互抑制作用有关。     

Effect of cadmium toxicity on micronutrient concentration,uptake and partitioning in seven rice cultivars

Heavy metal uptake, translocation and partitioning differ greatly among plant cultivars and plant parts. A pot experiment was conducted to determine the effect of cadmium (Cd) levels (0, 45 and 90 mg kg^?1 soil) on dry matter yield, and concentration, uptake and translocation of Cd, Fe, Zn, Mn and Cu in seven rice cultivars. Application of 45 mg Cd kg^?1 soil decreased root and shoot dry weight. On average, shoot and root Cd concentrations and uptake increased in all cultivars, but micronutrients uptake decreased following the application of 45 mg Cd kg^?1. No significant differences were observed between 45 and 90 mg kg^?1 Cd levels. On average, Cd treatments resulted in a decrease in Zn, Fe and Mn concentrations in shoots and Zn, Cu and Mn concentrations in roots. Differences were observed in Cd and micronutrient concentrations and uptake among rice cultivars. Translocation factor, defined as the shoot/root concentration ratio indicated that Cu and Fe contents in roots were higher than in shoots. The Mn concentration was much higher in shoots. Zinc concentrations were almost similar in the two organs of rice at 0 and 45 mg Cd kg^?1. A higher Cd level, however, led to a decrease in the Zn concentration in shoots.     

城郊菜地土壤重金属浓度及芦蒿吸收特征

A total of 222 surface soil samples and 40 plant samples were collected to investigate the spatial distribution and possible sources of soil heavy metals and to know the uptake and translocation of heavy metals from roots to different plant parts in a representative vegetable production area in the Baguazhou Island, a suburb of Nanjing City, East China. The arithmetic mean values of total Cd, Cr, Cu, Ni, Pb, and Zn concentrations in the soils were 0.314, 133, 41.0, 58.0, 31.8, and 114 mg kg^-1, respectively. All of these values were above the topsoil background values in the Nanjing area. Multivariate and geostatistical analyses showed that soil Cd contamination was derived mainly from agricultural practices. In contrast, Cu and Zn were derived mainly from soil parent materials and Pb from atmospheric deposition from highway gasoline stations. Artemisia selengensis, a locally important specialty vegetable, accumulated heavy metals primarily in the edible leaves. The general distribution of heavy metal concentrations in this plant species showed that the highest occurred in the leaves, intermediate in the stems and lowest in the roots. Cd had the highest concentration factor (root-to-soil ratio) and may pose increased health risks in the future to the local population through the consumption of contaminated vegetables.     

Cadmium and zinc accumulation in willow and poplar species grown on polluted soils

Woody plant species that produce high biomass have been proposed for use in phytoremediation technology. We investigated the accumulation of cadmium (Cd) and zinc (Zn) in Salix babylonica, S. caprea, S. dasyclados, S. matsudana × alba, S. purpurea, S. smithiana, Populus tremula, and P. nigra clones grown in a pot experiment on a Calcaric and a Eutric Cambisol (pH 7.2 and 6.4) of different levels of contamination (total metal concentrations in mg kg^–1 in soil A: 32.7 Cd, 1760 Zn; soil B: 4.34 Cd, 220 Zn). Generally, the tested clones tolerated large metal concentrations in soils and had larger Cd and Zn concentrations in leaves compared to the roots. The largest Cd concentrations in leaves were found in two clones of S. smithiana (440 mg kg^–1 on soil A; 70 mg kg^–1 on soil B). One of the S. smithiana clones had also the largest Zn concentrations (870 mg kg^–1) on soil B but accumulated slightly less Zn than a S. matsudana × alba clone (2430 mg kg^–1) on soil A. The Cd concentrations in leaves of both S. smithiana clones on soil A are the largest ever reported for soil‐grown willows. The bioconcentration factors of the best performing clone reached 15.9 for Cd and 3.93 for Zn on the less contaminated soil B. Also based on the metal contents in leaves, this clone was identified as the most promising for phytoextraction. The metal concentrations in leaves observed in the pot experiment do not reflect those found in a previous hydroponic study and the leaf‐to‐root ratios are clearly underestimated in hydroponic conditions. This demonstrates the need for testing candidates for phytoextraction crops on soils rather than in hydroponics. Our data also show that the phytoextraction potential should be tested on different soils to avoid misleading conclusions.     

PHOSPHORUS AND MANGANESE INTERACTIONS AND THEIR RELATIONSHIPS WITH ZINC IN CHELATOR-BUFFERED SOLUTION GROWN RUSSET BURBANK POTATO

Manganese (Mn)- and zinc (Zn)-driven antagonistic interactions with high available phosphorus (P) can result in negative impacts on potato cropping systems. Two chelator-buffered hydroponic experiments were conducted with Russet Burbank potato to elucidate P and Mn relationships and associated interactions with Zn. In both experiments, a P concentration decline in new shoots, old shoots, and roots resulted as solution Mn changed from deficient to sufficient followed by a P concentration rise as solution Mn changed to excessive concentrations. New and old shoot Zn concentrations generally increased with augmented solution Mn in the variable Mn experiment, but no significant changes were found in root Zn contents. Available Mn was observed to control plant P concentrations and to influence Zn uptake and translocation; thus, Mn has considerable impact on uptake and distribution of P and Zn and on P-Zn interactions in potato.     

Cadmium accumulation and distribution in sunflower plant

Cadmium (Cd) accumulation and distribution was studied in sunflower (Helianthus annuus L., public line HA‐89) plant. From an uncontaminated sandy loam brown forest soil with 162 μg kg^‐1 HNO₃/H₂O₂ extractable Cd the HA‐89 sunflower public line accumulated 114 ug kg^‐1 Cd in its kernels under open field conditions. This value is rather low as compared to data found by others. Sandy loam brown forest soil was treated with 0, 1 or 10 mg kg^‐1 of Cd to study the interaction of this heavy metal with young sunflower plants in a greenhouse pot experiment. The fresh weight and dry matter accumulation of sunflower plant organs (roots, shoots, leaves or heads) was unaffected by cadmium treatment of soil. The nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), iron (Fe), manganese (Mn), or zinc (Zn) uptake of sunflower plant organs was not influenced by lower or higher Cd‐doses, except sunflower heads where 10 mg kg^‐1 of Cd treatment of soil significantly reduced the uptake of Ca, Fe, and Mn. Although Cd reduced the Zn uptake of roots, its rate was statistically not significant. Cadmium was accumulated prevalently in roots (1.21 mg kg^‐1,4.97 mg kg^‐1, or 13.69 mg kg^‐1 depending on Cd‐dose), and its concentration increased also in shoots or leaves. In spite of the short interaction time, elevated concentrations of cadmium (0.78 mg kg^‐1, 1.34 mg kg^‐1, or 3.02 mg kg^‐1 depending on Cd‐dose) were detected in just emerged generative organs (heads) of young sunflower plants.