Joint effects of cadmium and lead on seedlings of four Chinese cabbage cultivars in northeastern China

In northeastern China, large area of vegetable land has been simultaneously polluted by cadmium (Cd) and lead (Pb). Joint e ects of Cd and Pb on Chinese cabbage (Brassica pekinensis L.) were investigated using the seed germination and sand culture method. Four Chinese cabbage cultivars including Kangbingjinchun (KB), Dongyangchunxia (DY), Qinglvwang (QL) and Qiangshi (QS) from Shenyang in northeastern China were adopted in this study. The results showed that there were positive linear relationships between the inhibitory rate of biomass, root and shoot elongation and the concentrations of Cd and Pb. In particular, root elongation was more sensitive to joint stress of Cd and Pb. The activity of superoxide dismutase and the content of malondialdehyde (MDA), soluble protein (SP) and proline (PRO) changed significantly with increasing exposure concentration of Cd and Pb. The decrement in the activity of antioxidative enzymes, the content of SP and accumulation of MDA were relatively low in KB and QS. PRO played an important role in resisting Cd and Pb stress.     

球果蔊菜脯氨酸的积累及与Cd耐性的关系

采用盆栽方法,以风花菜(Rorippa islandica)为对照植物,研究Cd超积累植物球果蔊菜[Rorippa globosa (Turcz.) Thell.]脯氨酸的积累、丙二醛含量、生物量及叶绿素含量的变化,及其与Cd生物积累的关系.结果显示,Cd处理能明显促进2种植物体内脯氨酸的积累,当土壤中Cd浓度≤25μg/g时,球果蔊菜叶片脯氨酸的积累效应尤为显著;此时叶片生物量、叶绿素及丙二醛含量与对照相比均无显著差异,表明其叶片脯氨酸的积累在一定程度上可缓解Cd胁迫造成的氧化损伤.相关分析表明,球果蔊菜根系脯氨酸可指示球果蔊菜根系中Cd的积累.     

黄丝草镉污染毒害及硒的缓解作用

研究了黄丝草(Potamogeton maackianus)培养过程中的Cd毒害及其Se的缓解作用.Se能缓解Cd胁迫导致的黄丝草叶绿素含量的降低、细胞膜透性增加和丙二醛(MDA)的积累.与单一的Cd处理相比,加入10mg/L Se后,过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活性有不同程度的增强,过氧化物酶(POD)活性有所减弱,表明它增强了对活性氧的清除能力,缓解了Cd对膜的伤害.可溶性蛋白含量则保持较高的水平,脯氨酸含量刚好相反,说明Se增强了黄丝草对Cd胁迫的抗性.然而,Se缓解Cd对黄丝草的毒害是有一定限度的,在富Se黄丝草的繁殖过程中,需及时检查重金属污染情况,防止重金属在饵料中的富集,以免造成对渔业的危害.     

Cd胁迫下超富集植物圆锥南芥抗氧化机理

采用土培的方法研究了不同Cd2+添加量(0、10、20、40、80、160、240mg.kg-1)对多金属超富集植物圆锥南芥(Arabis paniculata Franch)抗氧化酶(超氧化物歧化酶SOD、过氧化氢酶POD、抗坏血酸过氧化物酶CAT、过氧化物酶APX)活性、非酶物质(巯基SH、谷胱甘肽GSH、植物络合素PCs)含量以及生物量、叶绿素、丙二醛(MDA)、半胱氨酸(Cysteine)、脯氨酸(Proline)含量的影响.结果表明,随着Cd添加量的增加,圆锥南芥的生物量、Cd含量、富集系数、转运系数呈增加趋势,SOD活性、叶绿素含量呈下降趋势.POD、CAT、APX活性以及MDA含量均呈先升高后降低的变化趋势.圆锥南芥叶片中SH、GSH、PCs含量随Cd添加量的增加而增加,当Cd添加量为240mg.kg-1时,SH、GSH、PCs含量分别比对照提高了92.7%、70.2%、143.4%,表明SH、GSH、PCs在解毒Cd毒害中起着重要作用.     

Piriformospora indica confers cadmium tolerance in Nicotiana tabacum

Piriformospora indica, a root-colonizing endophytic fungus of Sebacinales, promotes plant growth and confers resistance against biotic and abiotic stresses. In order to confirm the influence of P. indica on growth, proline, malondialdehyde (MDA), chlorophyll, and cadmium (Cd) amounts in Nicotiana tabacum under Cd stress, hydroponics, pot and field trials were conducted. The results showed that P. indica can store Cd in plant roots and reduce leaf Cd content, reduce the concentration of MDA, and increase the proline and chlorophyll content and the activities of catalase, peroxidase, and superoxide dismutase under hydroponic Cd stress. RT-PCR analysis showed that the relative expression level of genes Gsh2, TaPCS1, oas1, GPX, and Hsp70 in colonized plants was 4.3, 1.4, 2.9, 1.7, and 6.9 fold higher than in un-colonized plants respectively. Cd exposure significantly reduced un-colonized plants'' agronomic traits compared to P. indica-colonized ones. Our results suggested that P. indica can sequester Cd in roots, so that much less cadmium was transported to leaves, and the increased concentrations of antioxidant enzymes, pigments and proline contents, as well as the higher expression of stress-related phytochelatin biosynthesis genes in P. indica-inoculated plants, may also serve to protect N. tabacum plants against oxidative damage, enhancing Cd tolerance.     

Effects of insoluble Zn, Cd, and EDTA on the growth, activities of antioxidant enzymes and uptake of Zn and Cd in Vetiveria zizanioides

A root-bag experiment was conducted to study the effects of insoluble Zn, Cd and ethylenediaminetetraacetic acid (EDTA) on the plant growth, activities of antioxidant enzymes, proline, glutathione (GSH), water-soluble proteins and malondialdehyde (MDA) of Vetiveria zizanioides, and its uptake capacity of Zn and Cd.The results showed that plant growth of V.zizanioides was inhibited by Zn and Cd.The shoot dry weight (SDW) and root dry weight (RDW) decrease by 0.3%, 8.0%, 9.4% and 10.4%, 15.1%, 24.2% compared to the control without EDTA addition, respectively.After adding EDTA, shoot and root dry weight decreased over 10% and 15% compared to results in the absence of EDTA, respectively.The toxicity from insoluble Zn and Cd in soil on SDW and RDW of V.zizanioides was in order: Zn+Cd > Cd > Zn.The activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), and contents of MDA and proline significantly increased, while the contents of GSH and water-soluble proteins markedly decreased with increasing Zn and Cd toxicity.With EDTA, shoot and root Zn concentrations increased in the Zn treatment by 7.3% and 37.4% compared to the plants grown in absence of EDTA.Shoot and root Cd concentrations in the combined Zn and Cd treatment with EDTA increased by 18.6% and 391.9% compared to the treatment without EDTA.However, Zn and Cd concentrations in shoot and roots decreased in the Cd treatment compared to the plants grown in absence of EDTA, with exception of root Cd concentration in the presence of EDTA).     

镉胁迫对菜豆幼苗基因组DNA多态性的影响

采用随机扩增多态性DNA (RAPD)等技术,检测不同浓度镉(Cd)胁迫对菜豆幼苗叶片DNA损伤及相关生理特性的影响.结果表明,随着Cd处理浓度(0,20,40,80mg/L)的增加,菜豆幼苗中的Cd含量及叶片中丙二醛(MDA)含量升高;叶片中可溶性蛋白、脯氨酸、还原型谷胱甘肽在低浓度(20mg/L)Cd处理下含量增加,中、高浓度(40,80mg/L)Cd处理下减少.选取8条寡核苷酸引物(10bp),利用RAPD随机扩增技术,对菜豆幼苗叶片细胞基因组DNA进行扩增,8条引物均产生特异性谱带.正常叶片基因组DNA的RAPD图谱得到46条谱带.与正常组相比,Cd处理下利用不同引物扩增得到的RAPD图谱发生改变,呈现不同程度的谱带强度增强或减弱、谱带缺失或新增,与对照的RAPD图谱存在明显差异.Cd胁迫下基因组模板稳定性下降,并随Cd处理浓度的增加,稳定性下降幅度增大.利用RAPD技术获得的DNA多态性变化,可指示镉毒害生物遗传效应,并为镉污染地区蔬菜品种的选育及镉毒性的评价提供依据.     

渗滤液灌溉对香根草胁迫及抗氧化系统的影响

以香根草(Vetiveria zizanioids)和渗滤液循环出水为实验材料,比较了不同体积浓度渗滤液灌溉对香根草胁迫相关生理指标及抗氧化系统的影响.结果表明,与对照相比,小于35%浓度的渗滤液灌溉6个月降低了香根草叶片脯氨酸(Pro)含量和相对膜透性,提高了叶绿素、蛋白质、抗坏血酸(AsA)、还原型谷胱甘肽(GSH)含量和叶绿素a/b值,过氧化物酶(POD)和超氧化物岐化酶(SOD)被激活,丙二醛(MDA)含量被控制在较低的水平上,表明低浓度渗滤液灌溉有利于香根草生长.大于35%浓度的渗滤液灌溉,随浓度的增大,香根草叶绿素含量和a/b值明显降低,MDA、H₂O₂、Pro进一步积累,相对膜透性显著增加,AsA、GSH含量下降,SOD和POD活性受抑制,表明高浓度渗滤液灌溉会造成活性氧产生和抗氧化系统清除之间的失衡,导致膜脂过氧化作用加剧,会加重对香根草的胁迫.灌溉6个月较3个月相比,叶绿素含量下降,Pro、MDA积累,表明灌溉时间延长也会导致胁迫加重.     

Effect of Cd on GSH and GSH-related enzymes of Chlamydomonas sp. ICE-L existing in Antarctic ice

Glutathione(GSH) and GSH-related enzymes play a great role in protecting organisms from oxidative damage. The GSH level and GSH-related enzymes activities were investigated as well as the growth yield and malonyldialdehyde(MDA) content in the Antarctic ice microalga Chlamydomonas sp. ICE-L exposure to the different cadmium concentration in this paper. The results showed that the higher concentration Cd inhibited the growth of ICE-L significantly and Cd would induce formation of MDA. At the same time, it is clear that GSH level, glutathione peroxidases(GPx) activity and glutathione S-transferases(GST), activity were higher in ICE-L exposed to Cd than the control. But GR activity dropped notably when ICE-L were cultured in the medium containing Cd. Increase of GSH level, GPx and GST activities acclimate to oxidative stress induced by Cd and protect Antarctic ice microalga Chlamydomonas sp. ICE-L from toxicity caused by Cd exposure. These parameters may be used to assess the biological impact of Cd in the Antarctic pole region environment.     

钝顶螺旋藻对Cd胁迫的生理反应

研究了钝顶螺旋藻在Cd胁迫下的生理指标的变化.结果表明,在CdCl2浓度为0～24 mg/L范围的Cd胁迫下,随着CdCl2浓度的增加,可溶性蛋白的含量明显低于对照组,抗氧化系统也受到了不同程度的影响.SOD(超氧化物歧化酶)和POD(过氧化物酶)活力呈先增后降趋势,其中POD活力增加的程度较大,最高可达对照的360%,最低也为对照组的262%.在0～24 mg/L浓度范围内,APX(抗坏血酸氧化酶)活力均低于对照组,但随CdCl2浓度的增加呈递增状态.CAT(过氧化氢酶)均高于对照组,整体呈增加的趋势.GSH-PX(谷胱甘肽过氧化物酶)活力均低于对照,最低降至对照组的25%.MDA(丙二醛)作为膜脂质过氧化的产物,其累积是Cd胁迫的突出的生理变化之一,MDA的含量与CdCl2的浓度呈正相关.     

叶面喷施2,3-二巯基丁二酸对水稻幼苗镉吸收转运及抗氧化系统的影响

稻米Cd超标问题已成为社会各界广泛关注的热点问题之一,探索降低Cd向地上部转运并缓解水稻Cd胁迫的新方法,对保障食品安全具有重要意义.本研究拟通过在水稻幼苗叶面喷施2,3-二巯基丁二酸(DMSA)评估利用该重金属螯合剂降低Cd向水稻地上部转运并缓解Cd胁迫的可行性.以我国南方水稻主栽品种之一中早35幼苗为研究材料,采用水培法研究了叶面喷施不同浓度DMSA对Cd在水稻幼苗体内吸收转运的影响,同时考察了对水稻幼苗丙二醛(MDA)、谷胱甘肽(GSH)含量以及对抗氧化酶过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活性的影响.结果表明,叶面喷施DMSA 0.2、 0.4和1.0 mmol·L~(-1) 4次后,水稻幼苗地上部Cd含量随着DMSA喷施浓度增加呈显著降低趋势, 3种处理浓度与对照相比分别降低22.1%、 39.7%和43.5%,但是对水稻幼苗根部Cd含量无显著影响;对地上部及根中K、Ca、Mg、Fe、Zn和Mn这6种矿质元素含量无显著影响;喷施4次DMSA后显著降低了幼苗地上部MDA和GSH含量,同时使CAT和SOD活性显著增加,有效缓解了Cd对水稻幼苗造成的胁迫效应.DMSA能抑制Cd从水稻根部向地上部转运,同时不影响对人体必需矿质营养元素的吸收和转运,具备成为水稻降Cd叶面调理剂的潜力.     

Variation of grain Cd and Zn concentrations of 110 hybrid rice cultivars grown in a low-Cd paddy soil

Enhanced Cd uptake and Zn depletion in rice grains and high potential for food Cd exposure by the high-yielding hybrid cultivars of China had been addressed. A field experiment was conducted in 2006 to determine the di erence in grain Cd and Zn between cultivars. Total 110 cultivars including super rice and common hybrid rice cultivars were grown on a single paddy soil (Entic Haplaquept) with a neutral reaction and low total Cd content. Grain Cd and Zn concentrations were determined with graphite atomic adsorption spectrophotometer (GFAAS) and flame atomic adsorption spectrophotometer (AAS) respectively.Wide variation of Cd content in grain was found in a range of 0.004–0.057 mg/kg, while the Zn content in a range of 10.25–30.06 mg/kg among the cultivars. Higher Cd but lower Zn concentration in grains of super rice cultivars was observed compared to the common hybrid ones. A highly significant positive linear correlation of grain Cd/Zn with grain Cd was found for super rice and common hybrid cultivars, meanwhile much higher slope for these hybrid cultivars than the reported non-hybrid cultivars was also observed. Using the limit value of the Chinese chemical guidelines for foods (MOHC and SSC, 2005), calculated potential risk of food Cd exposure with “Zn hungry” through diet intake was prominent with all the studied 110 hybrid rice cultivars, possessing high potential health problems for rice production in South China using the super rice cultivars. Breeding of genotypes of rice cultivars with low grain Cd and low Cd/Zn ratio is needed for rice production in acidic red soils where Cd bioavailability is prevalently high.     

Cd、Cu单一污染对小麦体内活性氧消除系统影响

采用溶液培养法,研究不同浓度Cd、Cu单一污染对小麦SOD、POD、CAT活性及MDA含量的影响。结果表明:(1)SOD和CAT活性对Cd胁迫反应较敏感,而POD活性变化不大,叶片中有效的活性氧自由基清除系统的平衡被打破,MDA含量增加;(2)Cu胁迫下,小麦叶片中MDA含量的变化趋势与根部的相反,在Cu处理浓度为25、50mg/L时,叶片中有效的活性氧自由基清除系统的平衡未被打破,MDA含量保持在较低的水平;而根部恰好相反,该系统出现了失衡现象,MDA含量偏高。     

Cd2+胁迫下中肋骨条藻细胞内多胺的生理响应

通过室内添加Cd2+培养中肋骨条藻(Skeletonema costatum),开展了Cd2+胁迫对中肋骨条藻生长的影响及藻细胞内超氧化物歧化酶(SOD)、二胺氧化酶(DAO)、多胺氧化酶(PAO)的活性以及丙二醛(MDA)和各形态多胺含量变化的实验,以探究多胺对于海洋微藻在重金属胁迫下的响应及生理作用.结果显示,Cd2+对中肋骨条藻的生长产生胁迫作用,且Cd2+浓度越大对藻细胞生长的抑制作用越强.Cd2+胁迫下中肋骨条藻细胞内MDA含量略有升高,SOD活性显著降低,DAO和PAO活性分别增强.随着Cd2+胁迫作用的增强,藻细胞内游离态腐胺(Put)、亚精胺(Spd)、精胺(Spm)含量先降低后升高;结合态Put、Spd和Spm含量先升高后降低;束缚态Put、Spm和Spd含量及Put总量和Spm总量升高.表明Cd2+胁迫会导致中肋骨条藻细胞产生氧化损害,同时细胞内DAO和PAO活性的增强以及游离态Put、束缚态Spd和Spm、Put总量和Spm总量的升高可能会增强藻细胞抵抗Cd2+胁迫的能力.     

Cd-Pb复合污染土壤钝化修复效率与生物标记物识别

为验证重金属钝化修复效率与植物生理生化特征的关系,采用盆栽试验研究了在Cd-Pb复合污染土壤中添加海泡石后,水稻幼苗叶片和根系中SOD(超氧化物歧化酶)活性、POD(过氧化物酶)活性、w(SP)(SP为可溶性蛋白)、C_MDA(丙二醛含量)、叶片光合色素含量以及稻草和糙米中w(Cd)、w(Pb)的变化情况. 结果表明:添加海泡石后,水稻幼苗叶片和根系SOD活性、根系POD活性均随海泡石添加量的增加呈先增后降趋势,叶片POD活性随海泡石添加量的增加而增大,其中,当海泡石添加量为1.0%时,其最大增幅达33.6%;与之相反,叶片C_MDA、叶片和根系w(SP)均随海泡石添加量的增加而降低,分别比对照处理降低8.0%~30.0%、6.3%~22.3%和17.7%~25.5%. 不同添加量海泡石处理下,稻草和糙米中w(Pb)分别降低20.5%~43.6%和18.7%~43.5%,w(Cd)分别降低8.3%~23.9%和21.2%~55.2%. 幼苗w(Chl)(Chl为叶绿素)、w(SP)与糙米w(Cd)之间,以及叶片C_MDA与糙米w(Cd)、w(Pb)间均呈显著正相关(P<0.05),而叶片POD活性与糙米w(Cd)之间呈极显著负相关(P<0.01),水稻幼苗叶片w(Chl)、w(SP)、C_MDA和POD活性可以作为评估海泡石钝化修复Cd-Pb复合污染钝化修复效率的分子生物标记物.      

外源精胺对镉胁迫下苎麻生理代谢的影响

采用水培实验法,研究了不同浓度和不同施加方式下外源精胺对苎麻镉污染毒害的缓解效应.结果表明,镉胁迫(10mg/L)使苎麻叶绿素、类胡萝卜素和可溶性蛋白质含量均不同程度地下降,膜脂过氧化程度提高,丙二醛含量增加;加入外源精胺后(以10^-5mol/L效果最佳),叶绿素、类胡萝卜素和可溶性蛋白质含量均显著上升,膜脂过氧化产物丙二醛含量明显降低,说明苎麻对镉的抗性得到显著提高,其中叶面喷洒并同时向营养液中加入精胺能更有效地缓解叶片的生理伤害,而仅叶面喷洒外源精胺则更有利于缓解根中镉的毒害.进入苎麻体内的镉约73.2%积累在根部,2种方式加入精胺均使得镉在苎麻体内的累积量下降,同时镉向地上部分的转移率提高.     

Cd对小白菜生长及氮素代谢的影响研究

采用水培的方法,研究了不同Cd2 水平(0、1、2.5、5、10 mg·L-1)对小白菜叶片中铵态氮、硝态氮、可溶性蛋白质、游离脯氨酸、叶绿素、部分营养元素含量以及蛋白水解酶、硝酸还原酶、谷氨酰胺转化酶与合成酶活性的影响.结果表明,低浓度的Cd处理(1 mg·L-1)刺激了小白菜的生长,提高了小白菜的生物量、叶绿素含量以及硝酸还原酶、谷氨酰胺合成酶与转化酶活性.Cd处理降低了小白菜对Cu、Ca、Fe、Mg的吸收,但促进了P的吸收.10 mg·L-1的Cd处理显著降低了可溶性蛋白质含量、硝酸还原酶、谷氨酰胺合成酶和转化酶活性(p＜0.05),提高了蛋白水解酶活性,不利于叶片中铵态氮与硝态氮的同化,造成叶片中铵态氮和硝态氮的累积.小白菜叶片中游离脯氨酸含量与铵态氮含量成极显著正相关(p＜0.01),说明小白菜叶片中游离脯氨酸的累积在一定程度上缓解了铵的毒害.     

Cadmium pollution enhanced ozone damage to winter wheat: biochemical and physiological evidences

Combined e ects of ozone (O3) and cadmium (Cd) on growth and physiology of winter wheat (Triticum aestivum L. cv. JM22) were determined. Wheat plants were grown without or with Cd and exposed to charcoal-filtered air (< 10 ppb O3) or elevated O3 (80 5 ppb, 7 hr/day) for 20 days. Results showed that O3 considerably depressed light saturated net photosynthetic rate (–20%), stomatal conductance (–33%), chlorophyll content (–33%), and total biomass (–29%) without Cd. The corresponding decreases were further enhanced by 45%, 56%, 60% and 59%, respectively with Cd, indicating a synergistic e ect of O3 and Cd on wheat. Ozone significantly increased the activity of superoxide dismutase (46%), catalase (48%) and peroxidase (56%). However, great increases in malondialdehyde (MDA) content (2.55 folds) and intercellular CO2 concentration (1.13 folds) were noted in O3+Cd treatment compared to control. Our findings demonstrated that the increased anti-oxidative activities in wheat plants exposed to O3+Cd might not be enough to overcome the adverse e ects of the combination of both pollutants as evidenced by further increase in MDA content, which is an important indicator of lipid peroxidation. Precise prediction model on O3 damages to crop should be conducted to ensure agricultural production security by considering environmental constraints in an agricultural system in peri-urban regions.     

稀土镧(La)及La(POA)_3对镉污染绿豆幼苗生理影响

以水培的方式研究了稀土元素镧及其配合物La(POA)3(HPOA=苯氧乙酸)对绿豆幼苗的生理生态影响。结果表明,单一镉(10mg/L)胁迫时,NR、CAT及POD活性下降,而MDA、Pro含量上升;较低浓度(5～30mg/L)的镧及其配合物能明显地促进绿豆幼苗生长,并且可以缓解镉对绿豆幼苗的胁迫作用,经镧及其配合物作用后,上述生理指标皆比单一镉胁迫时有明显的改善,而高浓度(100mg/L)的镧及其配合物对镉污染的缓解作用都减弱;另外,较低浓度(10、15、30mg/L)的La(POA)3对镉胁迫的缓解作用较镧更明显;随着作用时间的延长,镧及其配合物对绿豆幼苗镉污染的缓解作用均逐渐下降。     

菲-Cd单一与联合作用对毛蚶的氧化胁迫及损伤

采用静态染毒实验研究了菲和Cd2+单一作用与联合作用下胁迫9 d和清洁海水恢复过程中毛蚶体内超氧化歧化酶(SOD)、过氧化氢酶(CAT)活力和丙二醛(MDA)含量的变化。结果表明,在本实验的染毒条件下,毛蚶体内SOD和CAT活力呈现被诱导的趋势,MDA含量水平低于对照组。高浓度(菲50g/L,Cd 500g/L)比低浓度(菲10g/L,Cd 100g/L)的作用明显。菲对毛蚶的氧化胁迫作用大于Cd2+的作用,菲和Cd2+联合作用对毛蚶的氧化胁迫大于菲和Cd2+的单独作用。这两种污染物对毛蚶的氧化胁迫在消除污染后可以逐渐恢复,其中,Cd2+低浓度组(100g/L)在进行清水恢复后,SOD和CAT活力与对照组无显著性差异,说明毛蚶具有较好的抗氧化胁迫性和自我恢复能力。