铜胁迫对黄芪幼苗的生理学毒性与凹凸棒黏土的缓解作用

为探究黄芪幼苗对铜离子（Cu²⁺）胁迫的耐性机理以及凹凸棒黏土对Cu²⁺污染的缓解作用,研究了不同浓度CuSO₄（2~20mmol/L）胁迫对黄芪幼苗的生理学毒性与凹凸棒黏土的缓解作用.结果表明,2mmol/L CuSO₄胁迫使得根系Cu²⁺含量、H₂O₂（过氧化氢）含量、MDA（丙二醛）含量分别较对照显著上升1.82倍、1.04倍、2.14倍.CuSO₄胁迫浓度达8mmol/L时,根系SOD（超氧化物歧化酶）活性、根尖膜损伤程度和叶片Cu²⁺含量分别较对照显著上升1.13倍、1.12倍和2.62倍;同时,叶片PS Ⅱ（光系统II）实际光化学效率[Y（II）]、光化学淬灭系数（qP）、PSⅡ电子传递速率（ETR）和叶绿素含量较对照分别显著降低22.88%、24.44%、21.49%和28.31%,而NPQ和qN（非光化学荧光猝灭系数）则较对照分别显著上升2.35倍和1.58倍.根系POD（过氧化物酶）和CAT（过氧化氢酶）活性、可溶性糖和可溶性蛋白含量在8mmol/L CuSO₄处理下达到最高值后呈下降趋势.CuSO₄浓度为15~20mmol/L时,根系APX活性和叶片光适应下PS II潜在最大光化学效率（F_v'/F_m'）,以及幼苗全株鲜重、全株干重、地下部鲜重、地下部干重较对照显著下降.在非CuSO₄胁迫条件下,基质中凹凸棒黏土的存在使得幼苗根系MDA含量较对照显著降低15.93%,但未对其它所测生理学指标产生显著影响;在20mmol/L CuSO₄胁迫条件下,基质中凹凸棒黏土的存在使得幼苗根系和叶片中Cu²⁺含量分别显著下降30.78%和23.12%;同时显著缓解了20mmol/L CuSO₄胁迫对根系活性氧水平、抗氧化酶活性、膜脂质过氧化程度、根尖膜损伤程度、可溶性蛋白和可溶性糖含量,叶片PS II光化学活性和叶绿素含量的不良影响,以及对幼苗生长的抑制作用.研究结果表明,培养基质中凹凸棒黏土的存在能够显著降低幼苗组织中Cu²⁺的生物有效性,继而缓解CuSO₄胁迫对黄芪幼苗的生理学毒性作用.     

细胞分裂素类物质对镉胁迫下玉米幼苗生长和抗氧化酶活性及脯氨酸含量的影响

采用水培试验,研究了镉胁迫下喷施细胞分裂素类物质6-苄氨基嘌呤(6-BA)和激动素(KT)对玉米幼苗生长、叶片叶绿素含量、脯氨酸含量、植株镉含量和活性氧清除酶活性的影响.结果表明,与单纯镉胁迫相比,喷施6-BA和KT提高了玉米幼苗的生物量、根和地上部镉含量、叶绿素和脯氨酸含量,降低了叶片丙二醛(MDA)含量,促进了叶片过氧化物酶(POD)和过氧化氢酶(CAT)活性的升高,但对超氧化物歧化酶(SOD)活性的影响不明显.说明细胞分裂素类物质6-BA和KT可缓解镉胁迫对玉米幼苗的伤害,其机制可能与细胞分裂素物质能维持叶绿素稳定、刺激细胞内H2O2清除酶类活性及促进脯氨酸积累有关.当6-BA浓度在0～20mg·L-1之间时,其对玉米幼苗镉胁迫的缓解效应随喷施浓度的提高而增强,而KT的最适喷施浓度为70mg·L-1.     

Can phosphate compounds be used to reduce the plant uptake of Pb and resist the Pb stress in Pb-contaminated soils？

The effects of di erent phosphate-amendments on lead (Pb) uptake, the activities of superoxide dismutase (SOD) and the level of malondialdehyde (MDA) in cauliflower (Brassica oleracea L.) in contaminated soils with 2500, or 5000 mg P2O5/kg soil of hydroxyapatite (HA), phosphate rock (PR), single-superphosphate (SSP) and the mix of HA/SSP (HASSP) were evaluated in pot experiments. Results showed that the Pb concentrations in shoots and roots decreased by 18.3%–51.6% and 16.8%–57.3% among the treatments respectively compared to the control samples. The e ciency order of these phosphate-amendments in reducing Pb uptake was as follows: HASSPt HA > SSP t PR.With the addition of SSP, HA and the mix of HA/SSP, the SOD activity in shoot was reduced markedly (P < 0.05) compared with that in the control group. For example, the SOD activities in shoot by the treatments of HASSP, SSP, and HA in 5000 mg P2O5/kg were found to be only 51.3%, 56.2%, and 56.7%, respectively. Similar e ects were also observed on the level of MDA in the shoots with a decrease in 24.5%–56.3%. The results verified the inference that phosphate compounds could be used to reduce the plant uptake of Pb and resist the Pb stress in the plant vegetated in Pb-contaminated soils.     

UV/H_2O_2、UV/O_3和O_3体系中自由基产生效率的比较研究

以水杨酸(Salicylic Acid,SA)为模型探针分子,采用高效液相色谱法(HPLC)研究了UV/H2O2、UV/O3和O3等高级氧化工艺的羟基自由基(·OH)产生效率。实验结果表明,在SA初始浓度40mg/L,反应时间10min,氧化剂投加量2mmol/L的条件下,2,5-DHBA和2,3-DHBA为水杨酸与·OH反应的主要中间产物。三种高级氧化工艺中,UV/H2O2体系具有最高的羟基自由基(·OH)产生效率。     

灭菌和非灭菌土壤中高氯酸盐污染对水稻幼苗的影响

采用温室盆栽试验,研究灭菌与非灭菌土壤条件下2个品种水稻(GN和IR)幼苗对ClO₄-(高氯酸盐)污染的响应. 结果表明:无ClO₄-污染时,土壤灭菌可促进2个品种水稻的株高、根长和生物量的增长,但有ClO₄-污染时,灭菌处理反而显著抑制水稻生长;当施入ρ(ClO₄-)为0.1 mg/L时,土壤灭菌降低了水稻对ClO₄-的吸收积累,非灭菌组GN和IR分别有69.70%和88.55%的ClO₄-迁移到植物体内,而灭菌组则分别有21.55%和13.98%的ClO₄-迁移到植物体内;ρ(ClO₄-)为50.0 mg/L时,土壤灭菌反而增加了水稻对ClO₄-的吸收积累,灭菌组GN和IR叶片中的w(ClO₄-)分别是非灭菌组的3.67和5.88倍,但无论土壤是否灭菌,迁移到植物体内的ClO₄-所占比例均小于2%;灭菌组93%以上的ClO₄-残留在土壤中,而非灭菌组则有98%以上的ClO₄-转化成为其他物质. 土壤灭菌、ρ(ClO₄-)为50 mg/L处理能够显著降低土壤脲酶和过氧化氢酶的活性.      

模拟N、P污水对水稻幼苗过氧化物酶和超氧化物歧化酶的影响

以水稻为材料，研究了不同浓度的模拟Ｎ、Ｐ污水对幼苗过氧化物酶（ＰＯＤ，ＥＣ１．１１．１．７）和超氧化物歧化酶（ＳＯｏＤ，ＥＣ１．１５．１．１）及其同工酶等的影响，结果表明：在总氮浓度（Ｎｒ）为０─９０ｍｇ／Ｌ和总磷浓度（Ｐ＿Ｔ）为０─９ｍｇ／Ｌ范围内，ＰＯＤ与Ｎ、Ｐ浓度呈正相关，Ｎ＿Ｔ超过９０ｍｇ／Ｌ和Ｐ＿Ｔ超过９ｍｇ／Ｌ这一阈值后呈下降趋势，ＮＴ在０─１２０ｍｇ／Ｌ和Ｐ＿Ｔ在０─１２ｍｇ／Ｌ范围内，ＳＯＤ，丙二醛（ＭＤＡ）与Ｎ、Ｐ浓度呈显著正相关；Ｎ、Ｐ能诱导产生新的同工酶带，苗高、可溶性蛋白分别与Ｎ、Ｐ浓度呈显著负相关．     

Woody species Rhus chinensis Mill. seedlings tolerance to Pb: Physiological and biochemical response

Screening potential plant species is a crucial consideration in phytoremediation technology. Our previous study demonstrated that Rhus chinensis Mill. seedlings had potentials for phytoremediation of Pb contaminated soil. However, its bioaccumulation and tolerance characteristics remain unclear. Seedling growth, LMWOAs secreted by roots, Pb subcellular distribution and chemical forms, and mineral elements in R. chinensis tissues were evaluated under different Pb concentrations (0, 25, 50, 100, 200 and 400?mg/L) in culture solution at 14?days after planting. R. chinensis did not show visual symptoms of Pb toxicity under lower Pb treatments; however, Pb significantly declined the growth of seedlings under higher Pb treatments. Higher Pb stress also decreased the concentrations of nitrogen in leaves, but increased the concentrations of P and K in roots. Pb stress also decreased Mn concentrations in leaves. A great quantity of Pb was uptake and mostly retained in R. chinensis roots. Nonetheless, R. chinensis can still concentrate 459.3 and 1102.7?mg/kg Pb in leaves and stems, respectively. Most of Pb in R. chinensis tissues was stored in the cell wall with HAc-, HCl-, and NaCl-extractable form. LMWOAs secreted by R. chinensis roots showed a strong positive correlation with Pb concentrations in all plant tissues and with P in roots. Our results suggested that Pb deposited in the cell wall and integration with phosphate or oxalate might be responsible for the tolerance of R. chinensis under Pb stress in short period.     

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.     

Inhibition of ROS elevation and damage to mitochondrial function prevents lead-induced neurotoxic effects on structures and functions of AFD neurons in Caenorhabditis elegans

Here we investigated the possible roles of oxidative stress in the formation of decreased thermotaxis to cultivation temperature in lead (Pb)-exposed nematodes Caenorhabditis elagans. Exposure to Pb at the examined concentrations decreased thermotaxis behaviors, and induced severe deficits in the structural properties of AFD sensory neurons. Meanwhile, Pb exposure caused the induction of severe oxidative damage, reactive oxygen species (ROS) production, and mitochondrial dysfunction in young adults. Moreover, pre-treatment with the antioxidants dimethyl sulfoxide (DMSO), ascorbate and N-acetyl-L-cysteine (NAC), used to inhibit both the ROS elevation and the mitochondrial dysfunction caused by Pb exposure, at the L2-larval stage prevented the induction of oxidative damage and the formation of severe deficits in thermotaxis and structural properties of AFD sensory neurons in Pb-exposed young adults. Therefore, the formation of oxidative stress caused by Pb exposure may be due to both the induction of ROS elevation and damage to mitochondrial function, and oxidative stress may play a key role in inducing the neurotoxic effects on the structures and function of AFD sensory neurons in Pb-exposed nematodes.     

镉胁迫下小麦叶中超氧阴离子自由基的积累

在镉腔迫下，小麦中中超氧阴离子自由基的积累显增加，伴随ＭＤＡ含量升高，显示发生膜脂过氧化。镉腔迫使活性氧清降酶系统功能紊乱，其中ＳＯＤ酶活性下降，ＰＯＤ酶活性升高，在是ＣＡＴ酶活无显变化。     

Ultraviolet irradiation induced oxidative stress and response of antioxidant system in an intertidal macroalgae Corallina officinalis L.

The response of the antioxidant defense system of an intertidal macroalgae Corallina officinalis L. to different dosages of UV-B irradiation was investigated. Results showed that superoxide dimutase (SOD) and peroxidase (POX) increased and then maintained at a relatively stable level when subjected to UV-B irradiation. Catalase (CAT) activity under medium dosage of UV-B irradiation (Muv) and high dosage of UV-B irradiation (Huv) treatments were significantly decreased. Ascorbate peroxidase (APX) activity first remained unaltered and then increased in Huv treatment. In addition, the assay on isozymes was carried out using non-denaturing polyacrylamide gel electrophoresis (PAGE). The activities of some SOD isoforms were altered by UV-B. Two new bands (POX V and POX Ⅶ) appeared upon exposure to all three UV-B dosages. CAT Ⅲ activity was increased by low dosage of UV-B irradiation (Luv),whereas CAT Ⅲ and CAT Ⅳ disappeared when the alga was exposed to Muv and Huv. Two bands of APX (APX Ⅵ and APX Ⅶ)were increased and a new band (APX X) was observed under Huv exposure. H2O2 and thiobarbituric acid reacting substance (TBARS)increased under Muv and Huv treatments. Overall, UV-B protection mechanisms are partly inducible and to a certain extent sufficient to prevent the accumulation of damage in C officinalis.     

细叶蜈蚣草对悬沙胁迫的生理生态学研究

研究了悬沙对细叶蜈蚣草(Egeria nojas)营养生殖、叶绿素、抗氧化酶(超氧化物歧化酶和过氧化氢酶)等影响。实验结果表明:悬沙处理96h后,各组细叶蜈蚣草断枝均能发芽,其发芽率均在60%以上,悬沙浓度<4.0g/L时,断枝新芽生长较好,悬沙浓度>6.0g/L时,新芽生长受到影响;各组细叶蜈蚣草叶片的叶绿素a和叶绿素b以及总叶绿素含量均相差不大,叶绿素a/b值都在2.50以上,属于正常范围,变化幅度不大;各试验组中细叶蜈蚣草SOD和CAT相差不大,相对比较稳定,受到影响较小。因此,细叶蜈蚣草对悬沙胁迫具有较好的抗逆性,是一种在含沙量较高水体的生态修复实践中具有良好应用前景的水生植物。     

EDTA对2种芥菜型油菜幼苗富集Pb的效应

采用水培试验,研究了乙二胺四乙酸(EDTA)对Pb胁迫下2种芥菜型油菜(BrassicajunceaCzern.etCoss.)幼苗生长及富集Pb的效应.结果表明,单独用0.5和1.0mmol/LPb或EDTA处理可显著抑制植株的生长.与单独处理相比,Pb和EDTA复合处理可以降低各自的生物毒性.当Pb和EDTA等浓度复合处理时,植株生物量与对照植株无明显差异,说明游离态Pb或EDTA对幼苗具有毒害作用,而螯合态Pb-EDTA基本不具有生物毒性.EDTA处理促进Pb从根系向地上部运输,促进Pb在地上部积累.当c(EDTA)/c(Pb)为1/2时,地上部铅积累总量达到最高.随c(EDTA)的增加,根系铅积累总量反而下降.2个芥菜型油菜品种对EDTA的处理效应表现极为相似,生物量大的品种具有较高的Pb积累总量.      

Oxidative stress and DNA damages induced by cadmium accumulation

Experimental evidence shows that cadmium （Cd） could induce oxidative stress and then causes DNA damage in animal cells, however, whether such effect exists in plants is still unclear. In the present study, Vicia faba plants was exposed to 5 and 10 mg/L Cd for 4 d to investigate the distribution of Cd in plant, the metal effects on the cell lipids, antioxidative enzymes and DNA damages in leaves. Cd induced an increase in Cd concentrations in plants. An enhanced level of lipid peroxidation in leaves and an enhanced concentration of H2O2 in root tissues suggested that Cd caused oxidative stress in Vicia faba. Compared with control, Cd-induced enhancement in superoxide dismutase activity was significant at 5 mg/L than at 10 mg/kg in leaves, by contrast, catalase and peroxidaseactivities were significantly suppressed by Cd addition. DNA damage was detected by neutral/neutral, alkaline/neutral and alkaline/alkaline Comet assay. Increased levels of DNA damages induced by Cd occurred with reference to oxidative stress in leaves, therefore, oxidative stress induced by Cd accumulation in plants contributed to DNA damages and was possibly an important mechanism of Cd-phytotoxicity in Vicia faba plants.     

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.     

Ultraviolet irradiation induced oxidative stress and response of antioxidant system in an intertidal macroalgae Corallina o cinalis L.

The response of the antioxidant defense system of an intertidal macroalgae Corallina officinalis L. to different dosages of UV-B irradiation was investigated. Results showed that superoxide dimutase (SOD) and peroxidase (POX) increased and then maintained at a relatively stable level when subjected to UV-B irradiation. Catalase (CAT) activity under medium dosage of UV-B irradiation (Muv) and high dosage of UV-B irradiation (Huv) treatments were significantly decreased. Ascorbate peroxidase (APX) activity first remained unaltered and then increased in Huv treatment. In addition, the assay on isozymes was carried out using non-denaturing polyacrylamide gel electrophoresis (PAGE). The activities of some SOD isoforms were altered by UV-B. Two new bands (POX V and POX Ⅶ) appeared upon exposure to all three UV-B dosages. CAT Ⅲ activity was increased by low dosage of UV-B irradiation (Luv),whereas CAT Ⅲ and CAT Ⅳ disappeared when the alga was exposed to Muv and Huv. Two bands of APX (APX Ⅵ and APX Ⅶ)were increased and a new band (APX X) was observed under Huv exposure. H2O2 and thiobarbituric acid reacting substance (TBARS)increased under Muv and Huv treatments. Overall, UV-B protection mechanisms are partly inducible and to a certain extent sufficient to prevent the accumulation of damage in C officinalis.     

模拟酸雨和稀土镧对大豆幼苗的复合影响

采用水培法通过测定大豆幼苗叶片和根的POD活性、MDA含量、H2O2含量,研究了酸雨(AR)和稀土La(Ⅲ)对大豆幼苗POD活性和脂膜过氧化的复合影响。结果表明:单一La(Ⅲ)(RE1/20 mg/L、RE2/60 mg/L、RE3/100 mg/L、RE4/300 mg/L)处理时,低剂量La(Ⅲ)(RE1/20 mg/L)处理下,叶和根中POD活性高于CK而MDA和H2O2含量较之降低,高剂量La(Ⅲ)(RE2/60 mg/L、RE3/100 mg/L、RE4/300 mg/L)处理下,叶和根3项指标均升高。在酸雨(ARl/pH2.5、AR2/pH3.5和AR3/pH4.5)单独作用和RE+AR复合作用影响下,叶和根3项指标均升高;而且AR的pH越低,RE的浓度越高,叶和根中的3项指标增幅越大。RE1和AR复合处理下叶和根中3项指标的增幅低于AR单一处理,其它浓度RE和AR复合处理叶和根中的3项指标增幅高于各自单独作用。单一酸雨处理组各指标变幅为叶>根,单一镧和复合处理组各指标变幅为根>叶。     

氧化铜纳米颗粒对水稻幼苗根系代谢毒性的研究

为阐明氧化铜纳米颗粒(CuO NPs)暴露对植物生长的影响,分别用CuO NPs悬浮液、氧化铜大颗粒(CuO BPs)悬浮液和硫酸铜(CuSO4·5H2O)溶液进行处理,以蒸馏水(d H2O)作为对照,水培水稻幼苗,研究了CuO NPs对水稻幼苗根系相关生理生化行为的影响.结果表明,不同处理对水稻幼苗根系的影响有很大差异,经CuO NPs悬浮液处理后,水稻幼根受损较严重,根系活力明显降低,根内丙二醛(MDA)含量和过氧化氢(H2O2)含量显著升高,超氧化物歧化酶(SOD)和过氧化物酶(POD)活性明显增强.不同处理对水稻幼苗根的影响依次为:CuO NPs>CuSO4·5H2O>CuO BPs>d H2O.说明氧化铜纳米颗粒对水稻根的毒害作用不仅是由于释放离子引起的,纳米颗粒本身也起着重要作用,氧化损伤可能是CuO NPs的主要致毒机制之一.     

喜旱莲子草对Pb、Cd胁迫响应的研究

采用营养液培养法,以喜旱莲子草为对象,选择重金属Pb在浓度梯度0,0.1,10,50,100和200 mg/L条件下,Cd在浓度梯度0,0.01,1,10,20和40 mg/L条件下,研究了不同浓度Pb、Cd单一及复合胁迫对喜旱莲子草生长的影响。结果表明,在试验条件下,对单一Pb及Cd对喜旱莲子草生长及生理影响而言,与对照相比,当Pb处理浓度为0.1 mg/L时,植物最高株高和最长根长分别增加了3.8%和15%。随着Pb处理浓度增加到200 mg/L时,植物生长受到明显抑制,茎叶株高呈显著下降。当Cd处理浓度为1 mg/L时,与对照相比,植物最高株高和最长根长分别增加了9.0%和10.0%,随着Cd处理浓度增加(20~40 mg/L),植物生长受到明显抑制,茎叶株高呈显著下降。随Pb和Cd处理浓度增加,喜旱莲子草叶绿素含量呈下降趋势,POD活性先升后降,MDA含量呈上升趋势,植株体内Pb、Cd积累量呈上升趋势。在研究Pb、Cd对喜旱莲子草生长及生理胁迫的基础上,选择Pb、Cd不同配比浓度,探讨其对喜旱莲子草的复合胁迫作用,研究植物对重金属Pb、Cd富集特性,结果表明,低浓度Pb、Cd处理表现出相互促进吸收富集,高浓度处理表现出相互抑制吸收富集的特性。     

铀矿浸出液胁迫对种子萌发和幼苗生长及抗氧化酶影响

研究了不同浓度铀矿浸出液对水稻(Oryza sativa L.)、大豆(Glycine max(Linn.)Merr.)、玉米(Zea mays L.)和绿豆(Vigna radiata(Linn.)Wilczek.)的种子的萌发率、根系和幼苗的早期生长及其抗氧化酶活性的影响.结果表明:低浓度的铀矿浸出液使4种作物种子...