盐度对化感物质青蒿素胁迫下铜绿微囊藻生长及叶绿素荧光的影响

化感物质青蒿素已被证明具有良好的控制蓝藻水华的作用。为探究盐度存在情况下,青蒿素对铜绿微囊藻的胁迫作用是否受到影响,在0～15‰盐度条件下,测定青蒿素对铜绿微囊藻生长、叶绿素a含量以及叶绿素荧光参数的影响。结果表明：铜绿微囊藻具有一定的适盐性,5‰的盐度可以促进铜绿微囊藻生长,但盐度>10‰则对藻产生显著抑制作用。加入化感物质青蒿素后,低盐度对藻的促进作用消失,盐度强化了青蒿素对铜绿微囊藻的抑制和对光合系统的破坏,具体体现在破坏铜绿微囊藻光合色素、光合作用结构,降低光合反应中心的活性,降低PSⅡ受体侧的电子传递能力等方面。研究成果中为青蒿素在微咸水中的应用提供参考。     

商陆耐重金属Cd关键酶抗氧化酶的研究

研究商陆(Phytolacca americana L.)对Cd胁迫的抗氧化酶响应,对于揭示其耐Cd机制具有重要意义.商陆幼苗在200μmol/L或400 μmol/L CdCl2营养液中处理4 d,叶片活性氧自由基和MDA含量升高,膜透性增加,光合速率降低,表明Cd胁迫诱导产生氧化胁迫.随着Cd处理含量的提高和时间的...     

不同光强下镉胁迫对紫茉莉光合作用和抗氧化系统的影响

通过土培实验,比较分析了3种光强(全光照(HL)、50%全光照(ML)和10%全光照(LL))下镉胁迫(30 mg·kg-1)对紫茉莉植株生长、光合作用、光合色素、镉、镁、铁和钾含量、脂质过氧化、抗氧化酶活性、抗坏血酸和谷胱甘肽含量的影响.结果发现,镉胁迫显著降低紫茉莉叶片的净光合速率,对HL植株的抑制程度高于ML和LL植株;HL和LL植株最大光化学效率在镉胁迫下显著降低,而ML植株所受影响不明显;镉胁迫显著提高了紫茉莉叶片的暗呼吸速率,ML植株提高幅度最大.镉胁迫对紫茉莉植株生长的抑制作用显著,对HL植株的抑制最大.镉胁迫显著增加了紫茉莉叶片的镉含量,减小叶片叶绿素、类胡萝卜素、Mg、Fe和K的含量,对HL植株影响最大.镉胁迫下,HL植株超氧化物歧化酶和过氧化物酶活性增强,过氧化氢酶和抗坏血酸过氧化物酶活性降低,谷胱甘肽和抗坏血酸含量减小,过氧化氢和丙二醛含量、超氧阴离子产生速率增高,电解质渗漏加重.上述结果表明,镉加重了叶片氧化胁迫程度和强化了对紫茉莉生长的抑制,特别在高光强条件下.     

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.     

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.     

Interactions of zinc and cadmium toxicity in their effects on growth and in antioxidative systems in tomato plants (Solanum lycopersicum)

The interaction between zinc and cadmium was investigated in tomato plants (Solanum lycopersicum). Ten-day-old seedlings were treated with 10 μmol/L CDC12 associated to different concentrations of ZnC12 (10, 50, 100, and 150 μmol/L). Zn supply clearly reduced Cd accumulation in leaves and simultaneously increased Zn concentration. Cd induced oxidative stress in leaves as indicated by an increase in thiobarbituric acid-reactive substances (TBARS) level and chlorophyll breakdown. Furthermore, compared with control, Cdtreate plants had significantly higher activities of superoxide dismutase (SOD, EC 1.15.1.1), whereas, catalase (CAT, EC 1.111.1.6),ascorbate peroxidase (APX, EC 1.11.1.11), and glutathione reductase (GR, EC 1.6.4.2) activities were significantly suppressed by Cd addition. Zn supplementation, at low level, restored and enhanced the functional activity of these enzymes (SOD, CAT, APX and GR) as compared to Cd-alone-treated plants. The beneficial effect of adequate Zn level on Cd toxicity was confirmed by a significant decrease in TBARS level and restoration of chlorophyll content. However, when Zn was added at high level in combination with Cd there was an accumulation of oxidative stress, which was higher than that for Cd or excess Zn alone treatments. These results suggested that higher Zn concentrations and Cd are synergistic in their effect on plant growth parameters and oxidative stress.     

螯合型表面活性剂强化黑麦草修复Cd污染水体

采用水培试验,研究了新型螯合型表面活性剂N-十二酰基乙二胺三乙酸钠（LED3A）强化黑麦草修复Cd污染水体的效果,探讨了Cd或/和LED3A存在下黑麦草的生理响应以及LED3A对黑麦草除Cd性能的影响.结果表明：Cd显著抑制黑麦草生物量和光合色素含量,添加LED3A后抑制作用略有增强,CL100处理叶绿素和类胡萝卜素含量较CL0分别降低了15.50%和8.18%. LED3A对黑麦草的生长无显著影响,对黑麦草细胞的相对电导率（REC）有一定的提高,可使细胞膜渗透性增加以利于黑麦草对Cd的吸收.Cd胁迫下适量添加LED3A,能提高黑麦草植株超氧化歧化酶（SOD）和过氧化物酶（POD）活性,起到清除活性氧（ROS）、缓解Cd毒害和抑制丙二醛（MDA）积累的作用.最佳LED3A添加量下（50mg/L）,黑麦草植株的总Cd累积量和转移系数较Cd单独处理时分别提高了74.39%和67.96%,Cd的去除率达到55.98%.研究表明添加LED3A可有效提高植物对Cd的修复效率.     

Salinity elevates Cd bioaccumulation of sea rice cultured under co-exposure of cadmium and salt

Salt-tolerant rice (sea rice) is a key cultivar for increasing rice yields in salinity soil. The co-existence of salinity and cadmium (Cd) toxicities in the plant-soil system has become a great challenge for sustainable agriculture, especially in some estuaries and coastal areas. However, little information is available on the Cd accumulating features of sea rice under the co-stress of Cd and salinity. In this work, a hydroponic experiment with combined Cd (0, 0.2, 0.8 mg/L Cd²⁺) and saline (0, 0.6%, and 1.2% NaCl, W/V) levels and a pot experiment were set to evaluate the Cd toxic risks of sea rice. The hydroponic results showed that more Cd accumulated in sea rice than that in the reported high-Cd-accumulating rice, Chang Xianggu. It indicated an interesting synergistic effect between Cd and Na levels in sea rice, and the Cd level rose significantly with a concomitant increase in Na level in both shoot (r = 0.54, p < 0.01) and root (r = 0.66, p < 0.01) of sea rice. Lower MDA content was found in sea rice, implying that the salt addition probably triggered the defensive ability against oxidative stress. The pot experiment indicated that the coexistent Cd and salinity stress further inhibited the rice growth and rice yield, and the Cd concentration in rice grain was below 0.2 mg/kg. Collectively, this work provides a general understanding of the co-stress of Cd and salinity on the growth and Cd accumulation of sea rice. Additional work is required to precisely identify the phytoremediation potential of sea rice in Cd-polluted saline soil.     

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.     

旺盛期烟草对镉富集敏感性研究

采用盆栽试验方法,揭示了旺盛期烟草（云烟99）对镉的富集特点以及光合等生理指标对镉胁迫的响应.结果表明：当土壤镉含量分别为4.43,7.94,17.33和49.79mg/kg时,烟草茎、叶及地上部镉的富集系数（植物镉含量与土壤镉含量的比值）均大于1,转移系数（地上部镉含量与根镉含量的比值）也大于1,但镉含量未达到镉超富集植物的临界含量标准100mg/kg.当土壤镉含量为4.43mg/kg时,烟草的耐性较强.当土壤镉含量大于7.94mg/kg时,烟草的生物量、叶片光合色素含量、净光合速率、蒸腾速率、气孔导度和SOD活性均显著下降（P<0.05）,胞间CO₂浓度和MDA含量显著提高（P<0.05）.旺盛期烟草对镉富集比较敏感,建议烟草的种植要远离镉污染土壤或镉背景值较高的土壤.     

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.     

Effects of nitrogen and phosphorus concentrations on the bioaccumulation of polybrominated diphenyl ethers by Prorocentrum donghaiense

The growth, cellular total lipids, bioaccumulation amount, and bioaccumulation factors (BAFs) of 2,4,4 ′ -tribromodiphenyl ether (BDE28), 2,2 ′ ,4,4 ′ -tetrabromodiphenyl ether (BDE47), and 2,2 ′ ,4,4 ′ ,5-pentabromodiphenyl ether (BDE99) in a semi-continuous culture of Prorocentrum donghaiense were studied in relation to nitrate (0, 128, and 512 μmol/L) and phosphate (0, 8, and 32 μmol/L) concentrations. The BDE28, BDE47, and BDE99 content per cell under 0 μmol N/L were 3.77 × 10 6 , 3.95 × 10 6 , and 4.32 × 10 6 ng/cell, respectively, which were significantly higher than those under 128 and 512 μmol N/L. A nearly 5-fold increase in polybrominated diphenyl ether (PBDE) content per algal cell was found between 0 and 8 μmol P/L and between 8 and 32 μmol P/L. With increasing N and P concentrations, the PBDE content per volume of algal culture and the accumulation percentage of available PBDEs declined slightly. The BAFs for the PBDEs based on lipids showed that the logBAF lip under 0 μmol N/L was higher than those under 128 and 512 μmol N/L. The logBAF lip under 0 μmol P/L was higher than that under 8 μmol P/L but lower than that under 32 μmol P/L. Correlation analysis indicated a significant negative correlation between nutrient concentration and cellular total lipids, as well as the PBDE content per cell. The results indicate that different N and P concentrations change the total lipids content of P. donghaiense, thereby resulting in varying PBDE accumulation.     

Phytoremediation potential of charophytes: Bioaccumulation and toxicity studies of cadmium, lead and zinc

The ability for usage of common freshwater charophytes,Chara aculeolata and Nitella opaca in removal of cadmium (Cd),lead (Pb) and zinc (Zn) from wastewater was examined.C.aculeolata and N.opaca were exposed to various concentrations of Cd (0.25 and 0.5 mg/L),Pb (5 and 10 mg/L) and Zn (5 and 10 mg/L) solutions under hydroponic conditions for 6 days.C.aculeolata was more tolerant of Cd and Pb than N.opaca.The relative growth rate of N.opaca was drastically reduced at high concentrations of Cd and Pb although both were tolerant of Zn.Both macroalgae showed a reduction in chloroplast,chlorophyll and carotenoid content after Cd and Pb exposure,while Zn exposure had little effects.The bioaccumulation of both Cd and Pb was higher in N.opaca (1544.3 μg/g at 0.5 mg/L Cd,21657.0 μg/g at 10 mg/L Pb) whereas higher Zn accumulation was observed in C.aculeolata (6703.5 μg/g at 10 mg/L Zn).In addition,high bioconcentration factor values (> 1000) for Cd and Pb were observed in both species.C.aculeolata showed higher percentage of Cd and Pb removal (> 95%) than N.opaca and seemed to be a better choice for Cd and Pb removal from wastewater due to its tolerance to these metals.     

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.     

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。     

Interactions of zinc and cadmium toxicity in their effects on growth and in antioxidative systems in tomato plants （Solanum lycopersicum）

The interaction between zinc and cadmium was investigated in tomato plants (Solanum lycopersicum). Ten-day-old seedlings were treated with 10 mol/L CdCl2 associated to di erent concentrations of ZnCl2 (10, 50, 100, and 150 mol/L). Zn supply clearly reduced Cd accumulation in leaves and simultaneously increased Zn concentration. Cd induced oxidative stress in leaves as indicated by an increase in thiobarbituric acid-reactive substances (TBARS) level and chlorophyll breakdown. Furthermore, compared with control, Cdtreated plants had significantly higher activities of superoxide dismutase (SOD, EC 1.15.1.1), whereas, catalase (CAT, EC 1.111.1.6), ascorbate peroxidase (APX, EC 1.11.1.11), and glutathione reductase (GR, EC 1.6.4.2) activities were significantly suppressed by Cd addition. Zn supplementation, at low level, restored and enhanced the functional activity of these enzymes (SOD, CAT, APX and GR) as compared to Cd-alone-treated plants. The beneficial e ect of adequate Zn level on Cd toxicity was confirmed by a significant decrease in TBARS level and restoration of chlorophyll content. However, when Zn was added at high level in combination with Cd there was an accumulation of oxidative stress, which was higher than that for Cd or excess Zn alone treatments. These results suggested that higher Zn concentrations and Cd are synergistic in their e ect on plant growth parameters and oxidative stress.     

La对Cd伤害大豆幼苗的生态生理作用

以盆载法研究了Cd对大豆幼苗的伤害及La对Cd伤害的缓解效应。结果表明,500mg/L CdCl₂严重抑制大豆幼苗的代谢与生长,叶面喷布30mg/LLaCl³一次,能缓解Cd毒造成的伤害。实验证明,这与La能增加大豆幼苗光合速率,提高叶绿素含量与硝酸还原酶活性、降低细胞质膜透性与植株体内Cd含量、维持TTC还原力等多重作用相关。     

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.     

氯氰菊酯对小鼠脑细胞的氧化损伤及维生素E的抗氧化作用

以昆明小鼠为受试动物,随机分为6组,包括1个阴性对照组、3个氯氰菊酯染毒组、1个维生素E组和1个高剂量氯氰菊酯加维生素E组,染毒组按10,20,40mg/kg 3个剂量水平,维生素E的剂量为100mg/kg,灌胃染毒小鼠7d.以脑组织匀浆测定活性氧(ROS)、还原型谷胱甘肽(GSH)和丙二醛(MDA)的含量;以脑组织细胞测定DNA-蛋白质交联(DPC)系数.随着氯氰菊酯染毒剂量的升高,脑组织的ROS、MDA含量和DPC系数逐渐上升,GSH含量逐渐降低,各指标呈一定的剂量-效应关系.染毒剂量320mg/kg时,ROS含量(841.3±100.34)、GSH含量[(12.54±1.316)nmol/L]和DPC系数(0.054±0.004)有显著差异(P<0.05);染毒剂量340mg/kg时,GSH含量[(10.51±1.545)nmol/L]有显著差异(P<0.05),ROS含量(1014.3±81.67)、MDA含量[(2.849±0.218)μmol/L]和DPC系数(0.079±0.005)有极显著差异(P<0.01).高剂量染毒加维生素E组与高剂量染毒组相比较,脑组织的ROS、MDA含量和DPC系数均有下降,GSH含量上升.脑组织的ROS(719.5±74.56)、GSH[(16.52±1.985)nmol/L]和DPC系数(0.055±0.005)有显著差异(P<0.05),MDA含量[(1.662±0.265)μmol/L]有极显著差异(P<0.01).较高剂量(320mg/kg)的氯氰菊酯能造成小鼠脑组织的氧化损伤,维生素E有抗氧化作用.