甘露醇对拟南芥基因组DNA甲基化的影响

以拟南芥（Arabidopsis thaliana）为材料,研究不同浓度甘露醇处理下拟南芥幼苗生长发育及其基因组DNA的甲基化水平和变化模式。结果表明,用50、100、150和200mmol·L―1甘露醇处理拟南芥种子会对拟南芥幼苗的形态特征和生长态势产生影响;甲基化敏感扩增多态性（methylation-sensitive amplification polymorphism,MSAP）分析表明,经50、100、150和200mmol·L―1甘露醇处理后,基因组DNA甲基化比率分别为17.75%、21.15%、15.49%和46.10%。甘露醇处理使拟南芥发生基于DNA甲基化水平和模式改变的表观遗传变异。与对照相比,在50、100、150和200mmol·L-1甘露醇处理下拟南芥幼苗基因组DNA的甲基化和去甲基化比率分别为5.78%、15.48%、10.71%、33.73%及10.98%、5.36%、8.33%、7.69%。由此推测,5-甲基胞嘧啶百分含量随着甘露醇胁迫的增强而发生不同程度的变化。     

甘露醇对拟南芥基因组DNA甲基化的影响

以拟南芥(Arabidopsis thaliana)为材料, 研究不同浓度甘露醇处理下拟南芥幼苗生长发育及其基因组DNA的甲基化水平和变化模式。结果表明, 用50、100、150和200 mmol·L^―1甘露醇处理拟南芥种子会对拟南芥幼苗的形态特征和生长态势产生影响; 甲基化敏感扩增多态性(methylation-sensitive amplification polymorphism, MSAP)分析表明, 经50、100、150和200 mmol·L^―1甘露醇处理后, 基因组DNA甲基化比率分别为17.75%、21.15%、15.49%和46.10%。甘露醇处理使拟南芥发生基于DNA甲基化水平和模式改变的表观遗传变异。与对照相比, 在50、100、150和200 mmol·L^–1甘露醇处理下拟南芥幼苗基因组DNA的甲基化和去甲基化比率分别为5.78%、15.48%、10.71%、33.73%及10.98%、5.36%、8.33%、7.69%。由此推测, 5-甲基胞嘧啶百分含量随着甘露醇胁迫的增强而发生不同程度的变化。     

镉胁迫下萝卜基因组DNA甲基化敏感扩增多态性分析

应用甲基化敏感扩增多态性(MSAP)技术分析了重金属镉(cd)胁迫处理后萝卜基因组DNA甲基化程度的变化。结果表明,经50、250和500mg/L CdCl_2处理后,MSAP比率分别为37%、43%和51%,均高于对照(34%);全甲基化率(双链C~mCGG)分别为23%、25%和27%,而其对照为22%,表明重金属CdCl_2胁迫后,某些位点发生了重新甲基化。萝卜叶片DNA中总甲基化水平的增加与CdCl_2处理浓度呈显著正相关。甲基化变异可分为重新甲基化、去甲基化、不定类型以及与对照相同的甲基化模式等类型,Cd胁迫处理引起的植株基因组DNA甲基化程度的提高主要是重新甲基化。     

铜胁迫对拟南芥幼苗生长和基因组DNA甲基化的影响

通过Murashige and Skoog(MS)培养实验,利用甲基化敏感扩增多态性(methylation-sensitive amplified polymorphism,MSAP)技术研究Cu2+胁迫对拟南芥幼苗基因组DNA甲基化水平与甲基化模式的变化,同时比较其与幼苗鲜重、根系生长对Cu2+胁迫的敏感性。结果表明:0、0.25、1.0 mg獉L-1Cu2+处理15 d后,幼苗根长及鲜重变化差异不显著,而幼苗基因组MSAP率随Cu2+浓度的增加呈先增高后降低的趋势,分别为15.93%、16.28%和15.83%;高浓度Cu2+胁迫下(3.0 mg獉L-1),根长显著变短,鲜重显著降低,MSAP率为14.26%;Cu2+胁迫(0.25~3.0 mg獉L-1)下,拟南芥幼苗基因组超甲基化(M型)位点及去甲基化(D型)位点数均呈显著增加趋势,Msp I酶较Hpa II酶对胁迫反应更敏感。因此,拟南芥幼苗MSAP变化对低浓度Cu2+胁迫响应敏感,可作为Cu污染的早期诊断和生态风险评价。     

稀土元素铈对斑马鱼肝脏的遗传毒性

以稀土元素中丰度最大的铈(Ce)为代表污染物,以斑马鱼(Danio rerio)为受试生物,采用RAPD-PCR和MSAP-PCR技术研究Ce对斑马鱼基因组DNA损伤及DNA甲基化的影响。结果表明,不同浓度Ce~(3+)(0、5、10和20μmol·L~(-1))胁迫斑马鱼28天后,Ce~(3+)主要在斑马鱼肝脏中富集(BCF:5.49~9.33),其次为腮(BCF:3.58~4.49)和肌肉(BCF:0.13~0.25);RAPD-PCR分析显示,Ce~(3+)(10μmol·L~(-1))胁迫能够诱导斑马鱼肝脏DNA的损伤;MSAP-PCR分析显示,Ce~(3+)胁迫引起的斑马鱼肝脏基因组DNA甲基化总变化率分别为8.93%(CK)、9.12%(5μmol·L~(-1))、15.56%(10μmol·L~(-1))和28.83%(20μmol·L~(-1)),其中低浓度胁迫下,斑马鱼肝脏基因组DNA去甲基化(D)型显著增加,高浓度下,甲基化(M)型显著增加,DNA甲基化多态性亦随胁迫浓度的增大而变大;测序分析结果显示,这些特异性甲基化条带与zinc finger protein STZ/ZAT10、ABC transporter 1、cell cycle control phosphatase superfamily protein等基因具有较高的同源性;与RAPD标记相比,DNA甲基化标记对Ce~(3+)的胁迫响应具有高敏感性。研究结果深化了对稀土元素生物学效应的认识。     

5-脱氧杂氮胞苷抑制小鼠附植前的胚胎发育

DNA甲基化在哺乳动物发育过程中有关键作用．在小鼠附植前胚胎发育过程中,DNA甲基化一直处于动态变化过程中．通过将体外受精胚在5-AZA-CdR中持续培养,研究5-AZA-CdR对小鼠附植前胚胎发育的影响,为附植前胚胎发育机理的研究及5-AZA-CdR的毒副作用研究提供试验基础．从原核期加入不同浓度的5-AZA-CdR时,胚胎不能发育到桑椹胚(0.2 和1.0 μmol/L)和4-细胞胚(5.0 μmol/L);从2-细胞期加入时,胚胎阻滞于未致密化的8-细胞(0.2 和1.0 μmol/L)和3/4-细胞期(5.0 μmol/L);而当从4-细胞加入时,虽然胚胎能够发育到早期桑椹胚,但发育比例同对照相比显著降低(P < 0.05)．进一步检测凋亡、基因组DNA甲基化和整体转录活性,结果显示,高浓度的5-AZA-CdR导致8-细胞和早期桑椹胚发生早期凋亡,而低浓度的5-AZA-CdR引起8-细胞和早期桑椹胚基因组DNA甲基化的降低和转录活性的降低,并且这种降低呈浓度依赖性．所以加入低浓度的5-AZA-CdR时,胚胎的DNA甲基化降低,引起转录活性的降低,进而导致胚胎发育的停滞．     

极性生长的细胞中胞嘧啶甲基化的动态变化及其对GABA信号的响应

DNA胞嘧啶(C)的甲基化(5m C)在植物发育过程中具有重要的调节作用,多种环境因子如逆境胁迫、植物内/外源性因子等均会触发DNA甲基化的变化。为探讨γ-氨基丁酸(GABA)对植物发育的可能调节机制,本研究以极性生长的烟草花粉管和拟南芥根为材料,分析5m C的含量及其对GABA信号的响应。结果表明,1.0 mmol/L GABA能显著促进烟草花粉管和拟南芥根的极性生长;同时,GABA处理使烟草花粉管和拟南芥根的基因组中5m C含量显著降低、5-羟基胞嘧啶(5hm C)含量显著增加。5hm C是5m C去甲基化途径中的一个重要中间产物,本研究证实了GABA可以作为一种重要的外源信号调节DNA甲基化的动态变化。     

5-azaC对小麦幼苗生长及盐胁迫后DNA甲基化变异的影响

DNA甲基化是调节植物生长发育,调控逆境基因表达的表观遗传机制之一。该研究采用不同浓度的DNA甲基化抑制剂5-azaC处理耐盐性不同的春小麦种子,分析其对种子萌发及盐胁迫后叶片基因组DNA甲基化的影响,探究DNA甲基化与小麦耐盐性之间的相关性。结果表明:(1)5-azaC显著抑制幼苗根长伸长,降低根系鲜重和干重。(2)甲基化敏感扩增多态性(MSAP)分析发现,单独盐胁迫后甲基化水平上升, 5-azaC预处理材料经盐胁迫后甲基化水平呈下降趋势。(3)盐胁迫后基因组同时发生DNA去甲基化和DNA甲基化。敏盐品种‘新春6号’DNA去甲基化比率上升,DNA甲基化增加的比率下降;耐盐品种‘新春11号’DNA去甲基化比率和DNA甲基化增加的比率均上升,但去甲基化比率大于DNA甲基化增加的比率,说明盐胁迫引起的基因组DNA去甲基化为主,5-azaC预处理提高了盐胁迫下DNA去甲基化的比率。(4)DNA甲基化修饰位点序列分析发现,在核糖体亚基蛋白、蛋白激酶和转座子序列均存在DNA甲基化修饰现象,说明存在多种代谢途径共同参与了盐胁迫调控。     

氧化胁迫对Alkalibacterium sp. F26防御酶和辅因子的影响

将一株能够高产过氧化氢酶的低度嗜盐嗜碱茵Alkalibacterium sp.F26作为模式微生物,采用高效液相色谱技术测定胞内代谢物浓度,研究氧化胁迫对其防御酶活性和辅因子的影响.研究结果表明:相比低浓度H2O2(＜1 mmol/L)胁迫,此菌株在高浓度H2O2(＞1 mmol/L)胁迫下的应答表现曼为明显:经3 mmol/L H2O2胁迫后胞内CAT酶活为106.54 U/mg protein,是对照产量的1.76倍;ATP浓度则从对照浓度20.55 μmol/L下降到17.80 μmol/L;NAD 浓度自对照样品的69.89 μmol/L减少至31.77 μmol/L.由于ATP和NAD 浓度的减少,相比未经过H2O2胁迫菌体.细胞能荷值EC从0.77降低至0.68,NADH/NAD 则从0.08增加至0.41.然而,这种应答机制在细胞受到低浓度H2O2的胁迫后并不明显:除发现100 μmol/L H2O2能够导致细胞防御机制的激活而使胞内ATP浓度相比对照有所增加的情况外,经50 μmol/L和500 μmol/L H2O2胁迫后胞内ATP水平从对照的22.69 μmol/L只下降到22.38 μmol/L和13.70 μmol/L;并且此种胁迫条件下NADH浓度变化也不显著.     

拟南芥MLH1基因启动子甲基化作为镉胁迫生物标记物潜力评估

应用重亚硫酸盐测序技术,研究了镉(Cd)胁迫21 d后拟南芥幼苗错配修复基因Mut L-homologue1(MLH1)启动子甲基化的变化趋势。结果显示,拟南芥MLH1启动子区域为-346~+42(391 bp),含有71个胞嘧啶:16个Cp G、6个CHG(H为C、A或T)和49个CHH位点。对照植株Cp G、CHH和CHG位点的甲基化率分别为44.8%、40.5%和52.0%。随Cd胁迫浓度的增加,MLH1启动子区胞嘧啶位点发生超甲基化和去甲基化的位点数逐渐增加;这些位点的甲基化率均呈上升趋势,且均高于对照组(除CHG位点外)。MLH1启动子区域71个胞嘧啶中,Cp G6、Cp G9、CHH44和CHG4位点的甲基化多态性对Cd胁迫更敏感,且具有剂量-效应关系;其中0.25 mg·L-1Cd胁迫下,Cp G9位点为超甲基化,其甲基化变化率为20.0%,其他3个位点为去甲基化,其甲基化变化率分别为12.0%、20.0%和20.0%。相对于幼苗的其他生物学性状(叶片数、生物量及叶绿素含量),Cd胁迫下MLH1启动子甲基化变化更显著且敏感,上述4个胞嘧啶热点的甲基化多态性可作为检测Cd胁迫对植物遗传毒性效应潜在的、有效的生物标记物。     

A novel allelopathic substance, 13-epi-orthosiphol N,in Orthosiphon stamineus

Orthosiphon stamineus (Java tea) has been widely used as traditional herb and several bioactive compounds against animal cells have been isolated. However, no bioactive compound against plants has been reported. Therefore, we investigated possible allelopathic properties and substances in O. stamineus. Aqueous methanol extracts of O. stamineus inhibited root and hypocotyl growth of cress (Lepidium sativum) and lettuce (Lactuca sativa) seedlings. Increasing the extract concentration increased the inhibition, which suggests that O. stamineus may have allelopathic properties. When the extract was divided into an ethyl acetate and an aqueous fraction, the ethyl acetate fraction showed the stronger inhibitory effect. Thus, the ethyl acetate phase was further purified, and the main allelopathic substance was isolated and identified as 13-epi-orthosiphol N, a novel compound, by spectral data. 13-epi-Orthosiphol N inhibited root and hypocotyl growth of cress and lettuce at concentrations greater than 10 μmol/L. The concentrations required for 50% inhibition ranged from 41 to 102 μmol/L. These results suggest that 13-epi-orthosiphol N may be an allelochemical and main contributor to the growth inhibitory effect of O. stamineus and may have potential as a template for the development of new plant control substances.     

盐胁迫下荒漠共生植物红砂与珍珠的根茎叶中离子吸收与分配特征

西北荒漠地区C3小灌木红砂(Reaumuria soongorica)和C4半灌木珍珠猪毛菜(Salsola passerina)在特定环境下混生在一起,分布面积广阔。以采自腾格里沙漠边缘荒漠地带的天然野生珍珠猪毛菜和红砂群落的幼苗为材料,经0、100、200、300、400mmol/L NaCl盐溶液共同胁迫10 d,检测它们的含水量、主要矿质离子在根茎叶的含量与分布,揭示二者耐盐的共生协同的离子平衡适应机制。试验结果发现,珍珠猪毛菜叶片具有"吸钾排钠的"的耐盐特征,红砂叶片具备"吸钠排钾"的特征,吸收利用无机矿质离子具备互补效应。二者耐盐Cl、Ca和Si离子吸收与累积能力存在很大差异:随着盐胁迫程度加剧,红砂的根茎叶中Cl离子含量持续增加,并且为珍珠猪毛菜的2—5倍;珍珠猪毛菜根中Ca离子含量为红砂的2—3倍,但含量变化不显著;红砂根中Si离子含量迅速降低后稳定,并且是珍珠猪毛菜根的3—5倍,其他器官变化差异较小。因此,红砂与珍珠猪毛菜的共培养盐胁迫下根中吸收的离子侧重不同,红砂以Na、Cl、Si为主,珍珠猪毛菜以K、Ca为主。随着盐胁迫的程度加强,离子选择吸收系数S k,Na的变化趋势降低,表明二者叶部对Na的选择性减小,K的选择性吸收积累增大,增强了它们的抗盐性,最终使叶片所受盐害减小。总之红砂与珍珠猪毛菜共生的耐盐离子稳态机制显著不同,离子吸收与分布具有互补互利的效应。     

Inhibitory effects of leachate from Eupatorium adenophorum on germination and growth of Amaranthus retroflexus and Chenopodium glaucum

Amaranthus retroflexus L. and Chenopodium glaucum L. are two widely distributed destructive weeds. Their strong adaptability and massive seed production make them the hardest weeds to deal with. This present study intended to investigate the effect of leachate from Eupatorium adenophorum on the growth of these weeds and explore the potential to develop an environmental friendly strategy to use the leachate to control the weeds. Seeds of A. retroflexus L. and C. glaucum L. were soaked in solutions containing 0%, 0.6%, 1.25%, 2.5%, and 5% leachate from E. adenophorum leaves. A. retroflexus and C. glaucum seedlings grown in pots were sprayed with leachate solutions in the same concentration range. The effects of these leachate solutions on membrane permeability and germination of seeds, and growth and physiological characteristics of the seedlings were investigated. The highest concentration of leachate (5%) caused significant damage to the cell membrane of seeds of both weed species, whereas lower concentrations (0.6%) promoted repair of the membrane system, as reflected by higher and lower than control in relative conductivity (RC), respectively. Different concentrations of leachate showed distinct allelopathic inhibitory effects on the two weed species; lower concentrations showed weak inhibitory or even positive effects, whereas higher concentrations showed stronger inhibitory effects. Higher concentrations of leachate (2.5% and 5%) delayed germination and significantly decreased the emergence rate of the seeds, survival rate, and dry matter accumulation of the seedlings. When treated by 5% leachate, the emergence date of A. retroflexus was delayed by 3.6 d, emergence rate of the seeds and survival rate was 69.1% and 70.6% of the control, respectively, seedling dry matter was 48.6% less than the control; In the case of C. glaucum, the emergence date was delayed by 2.7 d, emergence rate of the seeds and survival rate was 45.1% and 58.6% of the control, respectively, seedling dry matter was 44.7% less than the control. There were significant interactions among the different concentrations of leachate and the length of treatment period with respect to activities of antioxidant enzymes, malondialdehyde (MDA) contents, and chlorophyll contents. Seedlings treated with 0.6%, 1.25%, or 2.5% leachate solution for 24–72 h showed increased superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities. When seedlings were treated with leachate solutions for 96 h, antioxidant enzyme activities and chlorophyll content decreased in A. retroflexus, but only CAT activity decreased in C. glaucum. When seedlings of the two weed species were treated with 5% leachate solution, CAT activity and chlorophyll content decreased and MDA content gradually increased with longer treatment times (from 24 to 96 h). The two weed species showed different allelopathic responses to E. adenophorum; A. retroflexus was more sensitive than C. glaucum. Based on the investigation, it could be speculated that the delayed germination and low germination rate of the weeds after treatment by leachate could be due to the fact that leachate damaged the membrane system of the seeds. By delaying germination, lowering the germination rate of the weeds and inhibiting seedling growth, leachate from E. adenophorum could provide an effective way of controlling the weeds.     

盐地碱蓬二型性种子及其幼苗对盐渍环境的适应性

研究了盐地碱蓬二型性种子中离子含量与刚萌发幼苗耐盐性之间的关系,以及盐分对砂培盐地碱蓬二型性种子的幼苗生长、离子含量及光合特性的影响.棕色种子中离子含量显著高于黑色种子.与对照相比,100和400 mmol/L NaCl对棕色种子幼苗伸长没有抑制作用,却显著抑制黑色种子幼苗的伸长.NaCl处理下棕色种子的幼苗地上部分干重和主茎一级分枝数比黑色种子幼苗高,但二型性种子的幼苗叶片中离子含量、叶绿素含量及光合放氧速率却没有明显差异.上述结果说明盐地碱蓬棕色种子较高的离子含量可能是棕色种子刚萌发幼苗耐盐性较强的重要原因.棕色种子幼苗较高的生物量可能与其较多的分枝数有关.二型种子的这些特征可能决定了其在群落建成中所起到的不同作用.     

扑草净对远志幼苗根系活力及氧化胁迫的影响

以远志(Polygala tenuifolia Willd.)为材料,应用组织化学和生物化学的方法研究不同浓度扑草净(0—400 mg/L)对远志幼苗生长、根系活力、膜脂过氧化、活性氧含量及抗氧化酶活性等的影响。10 mg/L扑草净对远志幼苗根系活力、细胞膜完整性及活性氧的积累几乎无显著影响,而25—400 mg/L扑草净处理则显著增加活性氧的积累,明显抑制根系活力且破坏细胞膜完整性;上述结果进一步被膜脂过氧化、质膜完整性、活性氧产生(O.2-和H2O2)的非损伤组织化学染色所证明。远志幼苗可通过多种抗氧化酶(SOD、POD、CAT、APX等)和非酶抗氧化剂(如脯氨酸)的相互协调作用,清除低浓度扑草净胁迫诱发产生的活性氧,减轻对细胞的伤害。研究结果表明,发芽期是远志对扑草净处理的敏感时期,较为安全的扑草净临界浓度为10 mg/L;25mg/L扑草净处理即引起远志幼苗氧化胁迫和膜脂过氧化,使细胞膜的完整性受到破坏,根系活力下降,抑制了远志幼苗的生长发育。该研究为远志抗除草剂胁迫机制及其栽培过程中除草剂的安全合理使用提供理论依据。     

Genome-wide identification of cytosine-5 DNA methyltransferases and demethylases in Solanum lycopersicum

Recent studies have reported that decreased level of DNA cytosine methylation in the global genome was closely related to the initiation of tomato (Solanum lycopersicum) fruit ripening. However, genome-scale analysis of cytosine-5 DNA methyltransferases (C5-MTases) and demethylases in tomato has not been engaged. In this study, 7 C5-MTases and 3 demethylases were identified in tomato genome, which probably contributed to DNA cytosine methylation level in tomato. The 7 C5-MTases were categorized into 4 subgroups, and the 3 demethylases were classified into 2 subgroups based on phylogenetic analyses. Comprehensive analysis of their structure and genomic localization was also performed in this paper. According to online RNA-seq data, 4 S. lycopersicum C5-MTase (SlC5-MTase) genes (SlMET, SlDRM1L1, SlDRM5, SlMET3L) were expressed higher than others, and one DNA demethylase gene (SlDML) was significantly changed during tomato fruit development and ripening. Furthermore, all these five gene expressions at breaker (BK) stage changed with 1-methylcyclopropene (1-MCP) treatment, indicating that they were regulated by ethylene directly or indirectly in tomato fruit. In addition, subcellular localization analysis indicated that SlDRM1L1 and SlDRM5 located in the nucleus might have responsibility for RNA-directed DNA methylation (RdDM). Collectively, this paper provided a framework for gene discovery and functional characterization of C5-MTases and DNA demethylases in other Solanaceae species.     

NaCl胁迫下沙枣幼苗生长和阳离子吸收、运输与分配特性

沙枣(Elaeagnus angustifolia L.)耐盐性强,是我国北方生态脆弱地区造林绿化的一个先锋树种。为探讨沙枣的盐适应机制,研究了不同浓度NaCl(0、100和200 mmol/L)胁迫30d对其水培幼苗生物量累积以及不同组织(根、茎、叶)K+、Na+、Ca2+和Mg2+吸收、运输与分配的影响。结果表明:盐胁迫不同程度地促进了沙枣苗根系生长;100 mmol/L NaCl胁迫对幼苗生物量累积无明显影响,而200 mmol/L则显著抑制了生物量累积;盐胁迫幼苗根、茎、叶中Na+含量以及K+-Na+选择性运输系数(S K,Na)和Ca2+-Na+选择性运输系数(S Ca,Na)显著或大幅度增加,而K+、Ca2+、Mg2+含量以及K+/Na+、Ca2+/Na+和Mg2+/Na+比值则显著或大幅度下降;200 mmol/L NaCl胁迫沙枣根Na+含量和根Na+净累积量分别为22.15 mg/g干重和1.87 mg/株(是对照的16.20倍和20.06倍),根成为Na+净累积量增加幅度最大的组织和Na+含量最高的组织;200 mmol/L NaCl胁迫沙枣茎、叶中的Na+含量以及冠组织Na+净累积量分别高达5.15、7.71 mg/g干重和3.29 mg/株(是对照的7.22倍、9.58倍和5.45倍),但幼苗仍能正常生长。综合分析认为,沙枣的盐适应机制是根系拒盐和冠组织耐盐,主要通过根系的补偿生长效应、根系对Na+的聚积与限制作用以及冠组织对Na+的忍耐来实现的,同时也与根、茎和叶对K+、Ca2+选择性运输能力显著增强有关。     

可降解螯合剂对镉胁迫下籽粒苋根系形态及生理生化特征的影响

采用盆栽试验研究了可降解螯合剂EDDS和NTA对镉胁迫下籽粒苋(Amaranthus hybridus L.)根系形态及生理生化特征的影响。结果表明:当螯合剂施入10 mg/kg的镉污染土壤后,籽粒苋根系生物量和总长等根系形态指标与对照无显著差异,过氧化物酶(POD)、过氧化氢酶(CAT)活性、谷胱甘肽(GSH)和可溶性蛋白含量显著上升。当螯合剂施入100 mg/kg的镉污染土壤后,籽粒苋根系生物量、总长、表面积、体积及侧根数比对照显著减少了12.30%—23.98%、17.01%—24.90%、41.87%—57.93%、16.46%—32.94%和23.48%—53.35%;EDDS的施入使籽粒苋根系POD、CAT活性、GSH和可溶性蛋白含量显著升高;而NTA施入后,根系中的POD活性比对照降低了4.12%—35.95%,并且CAT活性和可溶性蛋白含量在2 mmol/kg NTA处理下分别显著降低了14.66%—15.79%和26.81%—30.48%;EDDS和NTA施入后,GSH含量比对照显著升高了14.73%—65.65%和28.05%—84.10%。当镉处理浓度分别为10 mg/kg和100 mg/kg时,螯合剂的施入显著增强了籽粒苋根系对镉的吸收,比对照分别增加了40.76%—103.10%和15.03%—49.49%。因此,EDDS和NTA施入镉污染土壤后,通过影响籽粒苋根系形态和生理生化过程以响应重金属镉的胁迫。