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1.
锌对镉胁迫下马蔺生长、镉积累及生理抗性的影响   总被引:10,自引:0,他引:10  
通过溶液培养研究了不同浓度锌(Zn)对镉(Cd)胁迫下马蔺(Iris lacteavar. chinen-sis)生长、Cd积累及抗氧化酶活性等的影响.结果表明:加入1~100mg.L-1Zn后,Cd胁迫下马蔺地上部Cd含量变化不大,而地下部Cd含量显著增加并呈先增后降的趋势;1mg.L-1Zn处理下马蔺地下部Cd含量最高,比对照显著增加51.4%;Zn浓度高于1mg.L-1后Cd含量均出现不同程度的下降,但仍高于对照.与单独Cd处理(10mg.L-1)相比,添加低浓度Zn(1~10mg.L-1)后,马蔺地上部生物量和叶绿素含量呈增加趋势,丙二醛(MDA)含量降低;在10mg.L-1Zn处理下,叶绿素a、b含量达到峰值,分别增加5.21%和22.27%,MDA含量降低25.46%,表明低浓度Zn缓解了Cd对马蔺的毒害.随Zn浓度的增加,Zn对Cd毒害的缓解作用逐渐降低,当溶液中Zn达到一定浓度(100mg.L-1)时,马蔺毒害加重,其生物量、叶绿素含量均下降,MDA含量显著增加.在试验胁迫浓度范围内超氧化物歧化酶(SOD)、过氧化物酶(POD)活性始终呈增加趋势,表明马蔺在受到Cd胁迫及Cd-Zn共存的条件下SOD和POD起着重要的抗氧化保护作用.  相似文献   

2.
主要研究了 Cd、Cr( VI)单一及复合污染对菹草叶绿素含量和抗氧化酶系统的影响 ,研究结果表明 :随 Cd、Cr( VI)胁迫浓度的增加 ,菹草总叶绿素含量下降 ,单一 Cd处理 SOD活性下降 ,POD和 CAT活性表现出先升后降的趋势 ,Cd、Cr( VI)复合污染的效应明显大于单一污染的效应。  相似文献   

3.
主要研究了Cd、Cr(Ⅵ)单一及复合污染对菹草叶绿素含量和抗氧化酶系统的影响,研究结果表明:随Cd、Cr(Ⅵ)腔迫浓度的增加,菹草总叶绿素含量下降,单一Cd处理SOD活性下降,POD和CAT活性表现出先升后降的趋势,Cd、Cr(Ⅵ)复合污染的效应明显大于单一污染的效应。  相似文献   

4.
采用水培培养的试验方法,研究白花泡桐幼苗在锌 (Zn)、镉 (Cd) 单一及复合胁迫下的生理生化响应及对重金属的富集、转移特征变化。结果表明,单一及复合重金属胁迫下,白花泡桐的生物量、株高及过氧化物酶 (Peroxidase,POD) 活性均随处理浓度的增加而降低。在复合污染下,Zn、Cd在植株的株高及生物量上表现出拮抗作用。与对照比,单一胁迫下,随着Zn浓度的增加,白花泡桐叶绿素含量和过氧化氢酶 (Catalase,CAT) 活性先增加后减小,超氧化物歧化酶 (Superoxide dismutase,SOD) 活性升高,地上部丙二醛 (Malondialdehyde,MDA) 含量先减小后增加;随着Cd浓度的增加,叶绿素含量和过氧化氢酶 (CAT) 活性升高,超氧化物歧化酶 (SOD) 活性及地上部丙二醛 (MDA) 含量先增加后减小,复合胁迫下,则表现出更加复杂的生理响应。白花泡桐幼苗对Cd的富集部位集中在根部;对Zn的富集部位集中在地上部,且转移系数大于1.00;Zn的加入会促进重金属向地上部分的转移;白花泡桐具有对复合重金属污染地进行有效的生态恢复的潜力。  相似文献   

5.
镉与锌复合污染对栝楼幼苗生理特性的影响   总被引:2,自引:0,他引:2  
通过室内盆栽实验,研究镉(Cd)、锌(Zn)复合污染对栝楼(Trichosanthes kirilowii Maxim.)幼苗生理特性的影响.结果显示,随着Cd、Zn浓度的升高,叶绿素a、叶绿素b、总叶绿素、可溶性糖及紫外吸收物含量下降;超氧化物歧化酶(SOD)活性先升高再下降,过氧化物酶(POD)活性及类胡萝卜素含量呈升—降—升趋势;丙二醛(MDA)和可溶性蛋白含量分别呈S"型及倒N"型曲线变化.与对照相比,在不同浓度复合污染条件下,光合色素、可溶性糖、可溶性蛋白、紫外吸收物含量及SOD活性均有所下降,POD活性和MDA含量上升.研究表明,栝楼幼苗对Cd、Zn胁迫具有一定的耐受力,但高浓度Cd、Zn对幼苗正常生长有较为显著的抑制作用.  相似文献   

6.
镉胁迫对小麦幼苗生长及生理特性的影响   总被引:69,自引:7,他引:62  
主要研究了重金属Cd污染对小麦生长和部分生理特性的影响。结果表明,叶绿素含量在0 2 5mmol·L-1Cd处理浓度时达到峰值,随Cd浓度的增加,含量下降。超氧化物歧化酶(SOD)、过氧化物酶(POD)活性随Cd浓度的增加而增加。丙二醛含量和细胞膜透性同样呈上升趋势。根系活力表现为先升高后下降的变化趋势。Cd胁迫下,小麦的生长受到一定程度的抑制,并随溶液中Cd浓度的增加,抑制加重  相似文献   

7.
研究了不同Cd、Cu、Zn处理浓度对黑藻体内活性氧()产生及对抗氧化酶(SOD、POD、CAT)活性的分子毒理学效应以探讨高等水生植物抗氧化酶对重金属胁迫的反应。结果表明,三种重金属都不同程度地加快了产生速率;Cu使SOD、POD、CAT活性下降;Cd也都减弱了SOD和POD活性,而CAT活性在0.5—5mg/L处理浓度时增加;Zn对SOD活性也为抑制作用,当浓度为0.5—5mg/L时POD和CAT活性都上升。关联度分析发现Cd、Cu和Zn胁迫下黑藻起主要保护作用的分别为SOD、POD和CAT,而SOD最易受到影响。Cd、Cu处理下的叶绿素含量也都呈下降趋势,而0.5—5mg/L的Zn浓度刺激了叶绿素合成。所有Zn处理、0.5mg/L的Cu处理和0.5—1mg/L的Cd处理的叶绿素a/b值都大于对照值。除了Cu使可溶性蛋白含量减少外,0.5—5mg/L的Zn和0.5—1mg/L的Cd都使其含量增加。综合起来,Cu的毒性最强,其次为Cd,Zn最弱。致死阈浓度分别为:Cu:0.5—1mg/L;Cd:1—2mg/L;Zn:5—6mg/L。SOD是评价重金属对沉水植物毒性效应的灵敏指标。黑藻对水环境Cu污染反应敏感。  相似文献   

8.
镉胁迫对狭叶香蒲某些生理指标的影响   总被引:5,自引:2,他引:3  
利用水培法研究了Cd胁迫对狭叶香蒲(Typha angustifolia L.)某些生理指标的影响。结果表明,Cd浓度在0.4和1.0 mg.L-1时,狭叶香蒲的叶绿素含量呈上升趋势;Cd浓度高于1.0 mg.L-1时,叶绿素含量有所下降。当Cd浓度达1.5 mg.L-1时,狭叶香蒲的根系活力明显降低。随Cd浓度的增加,超氧化物歧化酶(SOD)和过氧化物酶(POD)活性基本呈现低浓度时上升高浓度时下降的变化趋势;丙二醛(MDA)含量则呈上升趋势。  相似文献   

9.
比较研究了水体中单一Cr6 及外施Zn2 后对水车前抗氧化酶系统(SOD、POD、CAT)和叶绿素含量的影响,以探讨金属元素联合作用机理。结果表明:单一Cr6 处理下,1 mg·L-1处理浓度可产生一定的积极刺激作用, 表现为提高了SOD、POD和CAT活性和增加了叶绿素含量。与单一Cr6 处理相比,施加不同浓度的Zn2 后都不同程度地削弱了保护酶活性,叶绿素含量下降的幅度也更明显。这表明Zn2 的加入,削弱了水车前保护酶系统的保护作用,使水车前对Cr6 胁迫的耐性减弱,协同作用的趋势显著。  相似文献   

10.
通过水堵实验,研究了不同浓度(0、50、200、400μmol/L)下和不同时间内(3、7、11d)Cd2+对石菖蒲(Acorus ta-tarinowii Sehott)叶片抗氧酶活性、叶绿素含量、脂质过氧化程度以及脯氨酸含量的影响.结果表明:(1)超氧化物歧化酶(SOD)活性在3d时随着胁迫浓度的增大而增加,但7d和11d时都是在50 μmol/L浓度下达到峰值,然后降低,但都高于对照;除400μmol/L处理下SOD随胁迫时间延长呈先降后升的趋势外,其余浓度处理下均升高.(2)过氧化物酶(POD)活性在胁迫3d和7d时均随着胁迫浓度的增大而增加,11d时在200 μmol/L处理下达到峰值,然后降低;各浓度处理组均随着胁迫时间的延长POD活性呈下降趋势.(3)过氧化氢酶(CAT)活性在不同时间内随着胁迫浓度的增加呈先增后降趋势,并且各浓度处理组的CAT均随胁迫时间的延长而增加.(4)叶绿素含量在不同胁迫时间内均在200μmol/L处理下达到峰值,然后降低;除400μmol/L处理下的叶绿素随胁迫时间延长而增加外,其余浓度处理组均呈下降趋势.(5)丙二醛(MDA)含量和脯氨酸(Pro)含量均随着胁迫浓度的增加和胁迫时间的延长而增加.研究结果分析表明石菖蒲对Cd2+胁迫有一定的耐受性.  相似文献   

11.
目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。  相似文献   

12.
国内外蝗害治理技术现状与展望   总被引:3,自引:0,他引:3  
张龙 《昆虫知识》2011,48(4):804-810
本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...  相似文献   

13.
N -substituted phenothiazines (PTs) and phenoxazines (POs) catalyzed by fungal Coprinus cinereus peroxidase and Polyporus pinsitus laccase were investigated at pH 4–10. In the case of peroxidase, an apparent bimolecular rate constant (expressed as k cat/K m) varied from 1 ×107 M−1 s−1to 2.6×108 M−1 s−1 at pH 7.0. The constants for PO oxidation were higher in comparison to PT. pH dependence revealed two or three ionizable groups with pK a values of 4.9–5.7 and 7.7–9.7 that significantly affected the activity of peroxidase. Single-turnover experiments showed that the limiting step of PT oxidation was reduction of compound II and second-order rate constants were obtained which were consistent with the constants at steady-state conditions. Laccase-catalyzed PT and PO oxidation rates were lower; apparent bimolecular rate constants varied from 1.8×105 M−1 s−1 to 2.0×107 M−1 s−1 at pH 5.3. PO constants were higher in comparison to PT, as was the case with peroxidase. The dependence of the apparent bimolecular constants of compound II or copper type 1 reduction, in the case of peroxidase or laccase, respectively, was analyzed in the framework of the Marcus outer-sphere electron-transfer theory. Peroxidase-catalyzed reactions with PT, as well as PO, fitted the same hyperbolic dependence with a maximal oxidation rate of 1.6×108 M−1 s−1 and a reorganization energy of 0.30 eV. The respective parameters for laccase were 5.0×107 M−1 s−1 and 0.29 eV. Received: 20 September 1999 / Accepted: 24 February 2000  相似文献   

14.
The nanomechanical properties of the coiled-coils of myosin are fundamentally important in understanding muscle assembly and contraction. Force spectra of single molecules of double-headed myosin, single-headed myosin, and coiled-coil tail fragments were acquired with an atomic force microscope and displayed characteristic triphasic force-distance responses to stretch: a rise phase (R) and a plateau phase (P) and an exponential phase (E). The R and P phases arise mainly from the stretching of the coiled-coils, with the hinge region being the main contributor to the rise phase at low force. Only the E phase was analyzable by the worm-like chain model of polymer elasticity. Restrained molecular mechanics simulations on an existing x-ray structure of scallop S2 yielded force spectra with either two or three phases, depending on the mode of stretch. It revealed that coiled-coil chains separate completely near the end of the P phase and the stretching of the unfolded chains gives rise to the E phase. Extensive conformational searching yielded a P phase force near 40 pN that agreed well with the experimental value. We suggest that the flexible and elastic S2 region, particularly the hinge region, may undergo force-induced unfolding and extend reversibly during actomyosin powerstroke.  相似文献   

15.
以白术(Atractylodes macrooephala Koidz.)二倍体组培苗为材料,对其四倍体诱导方法进行研究,共获得45个白术同源四倍体株系,为优良株系的选育提供了材料。此外,还分析比较了其中8个白术四倍体株系与二倍体的过氧化物酶同工酶(POD)的酶谱差异,发现四倍体各株系过氧化物酶同工酶谱比二倍体的均多了Rf0.310的谱带,且总过氧化物酶比活力也发生了很大改变,对探讨白术四倍体优良株系的生理生化机理具有一定的参考价值。  相似文献   

16.
研究放牧对草地植物生理活动的影响,对于揭未草地放牧演替的生理机制有重要意义,大量研究表明,家畜放牧对牧草光合作用、呼吸作用以及C和N吸收与转运的影响,可以分为生理伤害和生理恢复2个阶段,放牧通过改变草地冠层结构影响牧草光合作用,净光合作用速率短期内迅速下降,随着叶面积指数增加又逐渐上升,呼吸作用有相似的变化趋势,牧草放牧后再生长所需的C和N最初主要来自根系和留茬中的贮藏物质,此后随着牧草生长恢复逐渐由同化作用供给,C代谢与土壤N水平负相关,放牧后牧草生理活动变化与牧草遗传特性、种间竞争、家畜放牧特征、非生物环境等因素密切相关。  相似文献   

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3-O-Carboxymethylcoumestrol was prepared as the hapten for immunoassay by a partial alkylation of coumestrol with ethyl chloroacetate in acetone alkalized with potassium carbonate. 3-O-Ethoxycarbonylmethylcoumestrol was separated by column chromatography and finally was hydrolyzed with formic acid. 1H and 13C NMR data (APT, COSY, HMQC, and HMBC) revealed that the reaction was regioselective, as 3-O-ethoxycarboxymethylcoumestrol was the only monosubstituted derivative. The hapten was then conjugated to bovine serum albumin and used for immunization of rabbits. A radioimmunoassay (RIA) system was established based on the polyclonal antiserum and a 125I-labeled hapten-tyrosine methyl ester conjugate as the radioligand. Parameters of the RIA: sensitivity: 12 pg per tube, 50% intercept: 140 pg per tube, working range: 20-4000 pg per tube. The cross-reactivity of a panel isoflavonoid and lignan phytoestrogens was either negligible (e.g. formononetin 0.07%; biochanin A 0.06%) or not detectable at all. The major immunoreactive peak in HPLC fractions from an alfalfa extract had the same retention time as coumestrol standard and represented 94.8% of the signal. The remaining 5.2% of immunoreactivity was distributed between five minor peaks. We conclude that after the validation for particular matrices, the method will be a useful tool for analysis of coumestrol, especially in low volume and low concentration samples.  相似文献   

20.
Summary Three wheats and one triticale were grown, up to flowering stage, in pots on calcareous soil adjusted to a range of salinities (S1=3.5, S2=6, S3=8.5, and S4=11 mmhos/cm, 20°C, soilpaste extract) by adding solution consisting of 3∶2∶1 of Na-, Ca- and Mg chlorides in chemical equivalent amounts. Moisture in the pots was kept at 100% (W1), 40% (W2) and 20% (W3) of the available water. The vegetative growth, nitrogen and phosphate were affected by S and W treatments, chloride was affected only by S. The interaction S×W affected only dry weight. Varietal effect was observed between wheat as a group and triticale. Multiple quadratic regression equations of these properties on salinity and water revealed that the higher the available water the wider the range of tolerable salinity. Triticale was relatively more tolerant to water stress. Salinity increases Cl and decreases N, whereas water stress enhances N accumulation to a certain extent. However, in triticale at S3 and S4 the effect of water stress on N was overshadowed by the excessive salinity. This did not occur for the wheat (Florence). P trends were described. R2 for P was low (0.7435–0.3603) which made interpretations rather difficult.  相似文献   

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