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1.
硒对镉胁迫下水稻幼苗生长及生理特性的影响 总被引:51,自引:0,他引:51
采用溶液培养 ,研究不同浓度的硒和镉处理对稻苗的株高、叶片干重、叶绿素、还原糖、叶片丙二醛含量以及保护酶 SOD、POD、CAT活性的影响。结果表明 ,镉胁迫下稻苗矮化 ,镉毒害使叶片失绿 ,干重降低 ,还原糖含量下降 ,叶片 MDA含量增加 ,POD活性增强 ,而 SOD、CAT活性降低 ;硒可减轻镉对水稻的毒害 ,表现为 :减轻镉胁迫对株高增加的抑制 ,提高叶绿素含量 ,增加叶片干物质积累 ,提高叶片还原糖含量 (Cd0 .5 mg/ L加 Se 0 .1 0~ 0 .5 0 mg/ L例外 ) ,降低 MDA含量与 POD活性 ,提高 SOD、CAT活性 相似文献
2.
为探讨铅锌胁迫下轮叶黑藻(Hydrilla verticillate)的吸附水平及生理响应, 分别设置不同Pb2+(浓度梯度为0、0.01、0.05、0.10和0.20 mg/L)、Zn2+(浓度梯度为0、0.05、1.00、2.00和4.00 mg/L)浓度单一和复合胁迫轮叶黑藻28d, 测定其对铅锌的吸附量, 叶绿素a、叶绿素b、丙二醛(MDA)和总抗氧化能力(T-AOC)含量, 以及超氧化物歧化酶(SOD)和过氧化物酶(POD)的活性变化。结果显示: 高浓度(≥1.00 mg/L)的Zn2+可促进轮叶黑藻对Pb2+的吸收, 对Zn2+的吸附主要受Zn2+处理浓度的影响; 低浓度Pb2+和Zn2+可以促进叶绿素的合成, 高浓度(浓度≥1.00 mg/L)胁迫则抑制叶绿素的合成; 受到胁迫时其抗氧化系统会迅速作出反应, 但一定浓度的Pb2+与Zn2+在单一和复合胁迫下, 抗氧化系统受限, 说明抗氧化系统不能正常运转, 机体受到损伤。研究结果为轮叶黑藻在重金属修复中的应用提供一定的理论依据。 相似文献
3.
以黑藻(Hydrilla verticillata)为供试材料,采用Cd2+和Cu2+等两种重金属分别在5个浓度梯度水平下的河砂水培方法,研究Cd2+或Cu2+不同浓度胁迫对黑藻株高、生物量、成活率和叶绿素含量的影响,以及对黑藻叶片最小荧光(Fo)、最大荧光(Fm),PSⅡ最大量子产率(QYmax,)、稳态下的PSⅡ反应中心关闭程度(1-Qp_Lss)、稳态下的非光化学淬灭(NPQ_Lss)等光合荧光参数及其荧光成像的影响,探讨各个参数分别随镉、铜浓度递增的变化规律。研究结果表明,Cd2+胁迫下黑藻的株高显著下降,说明Cd2+可能对黑藻叶片的维管束结构产生伤害作用;Cd2+和Cu2+胁迫对黑藻鲜重均无显著影响,说明与水生植物自由水含量存在一定关系;Cd2+和Cu2+胁迫均使黑藻干重显著下降,其中Cu2+胁迫对黑藻干重的影响更显著,说明Cu2+胁迫对黑藻累积生物量的影响远大于Cd2+;Cd2+和Cu2+胁迫下叶绿素各值均呈下降趋势,而Cu2+胁迫对叶绿素的影响更大,说明Cu2+对黑藻叶绿体的毒害比Cd2+更大。随着Cd2+或Cu2+胁迫浓度梯度的增加,黑藻的叶绿素荧光参数(Fo、Fm、QYmax)呈显著下降趋势,(1-Qp_Lss)呈上升趋势,而NPQ_Lss先上升后下降。黑藻在不同重金属胁迫下的生理指标、荧光参数及成像特征等方面所表现出的变化差异性,反映出同等浓度下黑藻受重金属胁迫的影响程度为:Cd2+胁迫Cu2+胁迫;黑藻可以在Cu2+浓度低于1 mg/L的环境下具有正常的光合活性,可推测将黑藻用于低浓度Cu污染水域的修复;在Cu2+浓度达3 mg/L以上环境下黑藻即无法长时间生存,可推测黑藻可以作为Cd污染水环境的指示种。 相似文献
4.
铅、锌及其交互作用对鱼腥草(Houttuynia cordata)叶绿素含量及抗氧化酶系统的影响 总被引:5,自引:0,他引:5
采用营养液培养方法研究铅、锌及其交互作用对鱼腥草叶绿素含量及抗氧化酶系统的影响。实验结果显示,随着Pb浓度的增加,鱼腥草叶绿素含量逐渐降低但无显著变化。Zn在一定浓度下能提高鱼腥草叶绿素含量,而在高浓度Zn胁迫下,叶绿素含量急剧下降。鱼腥草叶片中SOD、POD和CAT3种酶活性都是随着Pb浓度的增加先上升后下降。随着Zn浓度的增加,SOD和CAT也是先上升后下降,POD则是逐渐上升。Pb—Zn交互作用增加了鱼腥草叶绿素含量,对SOD和POD活性具有抑制作用,对CAT活性影响不明显。同时研究结果还表明,单一Pb、Zn对鱼腥草叶绿素含量和抗氧化酶系统的影响大于Pb、Zn二者的共同作用,其中高浓度Zn对鱼腥草的伤害作用最大,而当溶液Pb处理浓度达到400mg/L时,鱼腥草仍能正常生长,说明鱼腥草具有较强的耐Pb能力。 相似文献
5.
采用营养液培养方法研究铅、锌及其交互作用对鱼腥草叶绿素含量及抗氧化酶系统的影响。实验结果显示,随着Pb浓度的增加,鱼腥草叶绿素含量逐渐降低但无显著变化。Zn在一定浓度下能提高鱼腥草叶绿素含量,而在高浓度Zn胁迫下,叶绿素含量急剧下降。鱼腥草叶片中SOD、POD和CAT 3种酶活性都是随着Pb浓度的增加先上升后下降。随着Zn浓度的增加,SOD和CAT也是先上升后下降, POD则是逐渐上升。Pb-Zn交互作用增加了鱼腥草叶绿素含量,对SOD和POD活性具有抑制作用,对CAT活性影响不明显。同时研究结果还表明,单一Pb、Zn对鱼腥草叶绿素含量和抗氧化酶系统的影响大于Pb、Zn二者的共同作用,其中高浓度Zn对鱼腥草的伤害作用最大,而当溶液Pb处理浓度达到400mg/L时,鱼腥草仍能正常生长,说明鱼腥草具有较强的耐Pb能力。 相似文献
6.
Cd、Zn复合污染对水车前叶绿素含量和活性氧清除系统的影响 总被引:49,自引:3,他引:46
主要研究了重金属Cd、Zn单一及复合污染对水车前叶绿素含量和活性氧清除系统的影响。超氧化物歧化酶 (SOD)、过氧化物酶 (POD)、过氧化氢酶 (CAT)活性都在 0 1mg·L-1Cd处理浓度时达到峰值 ,随培养浓度的增加 ,活性下降。叶绿素含量则随处理的浓度的上升而呈递减趋势。在各Cd处理梯度中加入Zn后 ,随加入Zn浓度的增大 ,上述各指标与单一Cd处理差异显著性增强 ,表明Zn增强了Cd的毒害作用 ,显示出协同作用的趋势 相似文献
7.
锌、镉及其复合胁迫下白花泡桐幼苗的生理及富集特征 总被引:1,自引:0,他引:1
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
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为了探讨利用黄瓜毛状根来修复重金属镉(Cd)污染的可能性, 研究了重金属Cd单独及其与锌(Zn)组合对黄瓜毛状根生长及其抗氧化酶SOD、POD活性变化的影响。结果表明, Cd≤10 mg/L仅在培养5~15 d间促进黄瓜毛状根生长, 使根增粗; 而Cd≥15 mg/L则抑制黄瓜毛状根生长, 浓度愈高抑制作用愈明显, 侧根变得短而细小。在供试的不同浓度Cd培养的黄瓜毛状根中, 除10 mg/L Cd外, 其余Cd浓度培养的黄瓜毛状根可溶性蛋白含量随着培养时间的延长而逐渐下降; 但其POD和SOD活性则随着培养时间的延长而逐渐升高。与对照(仅添加25 mg/L Zn)相比, 仅1 mg/L Cd+ 25 mg/L Zn组合在培养7~15 d期间促进黄瓜毛状根生长; 其余浓度Cd和25 mg/L Zn组合都抑制黄瓜毛状根的生长, 且Cd浓度愈高抑制作用越强, 侧根数目更少且短小, 侧根根尖变得肿胀; 同时, 除培养5 d外, 25 mg/L Zn和不同浓度Cd组合培养的黄瓜毛状根的生物量、POD和SOD活性均比单独添加对应浓度Cd培养的毛状根降低, 但其可溶性蛋白含量则较之明显提高。结果表明: 黄瓜毛状根具有较强的重金属Cd耐受能力, 高浓度Cd则抑制其生长; 而镉和锌组合会随着培养时间的延长而加重Cd对黄瓜毛状根生长的抑制作用。 相似文献
9.
Hg2+、Cd2+和Cu2+对菹草光合系统及保护酶系统的毒害作用 总被引:50,自引:2,他引:48
研究了Hg2 、Cd2 、Cu2 对高等水生沉水植物菹草光合系统及保护酶系统的毒害作用。结果表明 :3种离子均使菹草叶片叶绿体自发荧光强度、叶绿素含量、光合速率降低。Hg2 、Cd2 、Cu2 对菹草保护酶系统存在不同的影响 ,短时间低浓度条件下 ,诱导超氧化物歧化酶 (SOD )、过氧化氢酶 (CAT)、过氧化物酶(POD)活性上升 ,随着污染时间的延长、污染浓度的增加 ,酶活性下降 ,其中SOD活性上升持续时间最长 ,下降最慢。 3种离子均使菹草可溶性蛋白含量减少。Hg2 、Cu2 毒性较强 ,Cd2 毒性较弱。Hg2 、Cu2 对菹草的致死浓度为 0 .5~ 1mg/L ,Cd2 为 1~ 2 .5mg/L 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
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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
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国内外蝗害治理技术现状与展望 总被引:3,自引:0,他引:3
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
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放牧对牧草光合作用、呼吸作用和氮、碳吸收与转运的影响 总被引:9,自引:1,他引:8
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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Juozas Kulys Kastis Krikstopaitis Arturas Ziemys 《Journal of biological inorganic chemistry》2000,5(3):333-340
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
16.
白术同源四倍体的诱导和鉴定及其与二倍体过氧化物酶的比较 总被引:18,自引:0,他引:18
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
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Coiled-coil nanomechanics and uncoiling and unfolding of the superhelix and alpha-helices of myosin 下载免费PDF全文
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
19.
Lapcík O Stursa J Kleinová T Vítková M Dvoráková H Klejdus B Moravcová J 《Steroids》2003,68(14):1147-1155
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.
Among tetrapods, evidence for postrenal modification of the urine by the distal digestive tract (including the colon and cloaca) is highly variable. Birds and bladderless reptiles are of interest because the colon and cloaca represent the only sites from which water and ions can be reclaimed from the urine secreted by the kidney. For animals occupying desiccating environments (e.g., deserts and marine environments), postrenal modification of the urine may directly contribute to the maintenance of hypo‐osmotic body fluids. We compared the morphology and distribution of key proteins in the colon, cloaca, and urogenital ducts of watersnakes from marine (Nerodia clarkii clarkii) and freshwater (Nerodia fasciata) habitats. Specifically, we examined the epithelia of each tissue for evidence of mucus production by examining the distribution of mucopolysaccharides, and for evidence of water/ion regulation by examining the distribution of Na+/K+‐ATPase (NKA), Na+/K+/Cl? cotransporter (NKCC), and aquaporin 3 (AQP3). NKCC localized to the basolateral epithelium of the colon, urodeal sphincter, and proctodeum, consistent with a role in secretion of Na+, Cl?, and K+ from the tissue, but NKA was not detected in the colon or any compartment of the cloaca. Interestingly, NKA was detected in the basolateral epithelium of the ureters, suggesting the urothelium may play a role in active ion transport. AQP3 was detected in the ureters and coprodeal complex, consistent with a role in urinary and fecal dehydration or, potentially, in the production of the watery component of the mucus secreted by the coprodeal complex. Since no differences in general cloacal morphology, production of mucus, or the distribution of ion transporters/water channels were detected between the two species, cloacal osmoregulation may either be regulated by proteins not examined in this study or may not be responsible for the differential success of N. c. clarkii and N. fasciata in marine habitats. J. Morphol. 2011. © 2011 Wiley Periodicals, Inc. 相似文献