Enhancement of cyclophosphamide-induced antitumor effect by a novel polysaccharide from Ganoderma atrum in sarcoma 180-bearing mice

The aim of this study was to investigate the enhancement of Ganoderma atrum polysaccharide (PSG-1) on cyclophosphamide (CTX)-induced antitumor effect in sarcoma 180 (S-180)-bearing mice. Results showed that both CTX and PSG-1 delayed tumor growth and resulted in tumor apoptosis. The combined regimen was superior to either modality alone. Moreover, the combined treatment-induced apoptosis was mediated via mitochondrial pathway, as evidenced by alterations of Bcl-2 family proteins, loss of mitochondrial membrane potential (Δψ(m)), cytochrome c release, and caspases activation. Our results also showed that thymus and spleen indexes, lymphocytes proliferation, and concentrations of cytokine in the CTX group were decreased, which were alleviated by PSG-1. Additionally, the combined treatment ameliorated oxidative stress as compared with CTX alone. Taken together, we conclude that PSG-1 improved the antitumor effect of CTX, possibly in part mediated by enhancing the induction of apoptosis via mitochondrial pathways, activating host immune function, and modifying the redox system in S-180-bearing mice.     

Heat-killed cells of lactobacilli skew the immune response toward T helper 1 polarization in mouse splenocytes and dendritic cell-treated T cells

It is believed that probiotics play an important role for the health of the host, including modulation of immune responses. Most studies have focused on the immunomodulatory effects of viable cells of lactic acid bacteria; however, we investigated those of heat-killed cells of lactic acid bacteria in this study. We first observed the effects on immune functions via stimulating splenocytes with three heat-killed Lactobacillus strains. Furthermore, we also investigated the effect of mouse dendritic cells (DCs) treated with these heat-killed Lactobacillus strains on T cell responses. The results showed that these Lactobacillus strains were able to stimulate cell proliferation and interleukin (IL)-10, IL-12 p70, and interferon (IFN)-gamma production but not transforming growth factor (TGF)-beta in splenocytes. In addition, these heat-killed Lactobacillus strains also stimulated high-level secretion of IL-12 p70 in DCs and switched T cells to T helper (Th) 1 immune responses, as evidenced by the elevated secretion of IFN-gamma but not IL-5, IL-13, and TGF-beta. These results showed that lactobacilli play a potentially important role in modulating immune responses and allergic reactions.     

胁迫对菜用大豆种子抗坏血酸-谷胱甘肽循环的影响

采用蛭石栽培,在100 mmol/L NaCl 胁迫下,对耐盐性不同的两个菜用大豆［Glycine max (L.)Merr.］品种种子的过氧化氢（H2O2）含量及抗坏血酸-谷胱甘肽（AsA-GSH）循环进行了研究。结果显示,NaCl胁迫显著增加了菜用大豆种子的H2O2含量,但耐盐品种 绿领特早的增幅低于盐敏感品种理想高产95-1。NaCl胁迫期间,绿领特早种子中抗坏血酸过氧化物酶（APX）、脱氢抗坏血酸还原酶（DHAR）、谷胱甘肽还原酶（GR）活性,AsA、GSH含量以及AsA/DHA值和GSH/GSSG值的增幅高于同期的理想高产95-1,或降幅低于同期的理想高产95-1; 脱氢抗坏血酸（DHA）、氧化型谷胱甘肽（GSSG）含量的增幅低于同期的理想高产95-1。表明 绿领特早种子在胁迫期间能够保持较高的AsA-GSH循环效率,可有效地抑制H2O2的积累,这可能是其耐盐性较强的重要原因之一。     

硒镉伴生对富硒土壤柑橘生长及生理代谢的影响

为保障富硒柑橘的安全生产,明确富硒土壤硒镉伴生现象对柑橘生长、硒镉吸收转运和抗氧化能力的影响,采用盆栽试验,以一年生大雅柑橘为试验材料,研究添加硒代蛋氨酸(SeMet,CK,模拟富硒土壤)和添加SeMet与镉(模拟富硒土壤硒镉伴生)对富硒土壤柑橘的生长指标、硒镉含量、叶片还原型抗坏血酸-谷胱甘肽(AsA-GSH)循环效率的影响。结果表明,与CK相比,富硒土壤中,硒镉伴生增加了柑橘叶片叶绿素a+b、叶绿素a、叶绿素b和类胡萝卜素含量,但对株高、新梢长度、新梢数量以及根茎叶的干物质量影响不显著;在富硒土壤中,硒镉伴生显著增加了大雅柑橘硒含量和硒的富集系数(BCF),降低了硒的转运系数(TF);硒和镉主要分布在根系,其次是叶片和茎;在AsA-GSH循环中,硒镉伴生使过氧化氢(H₂O₂)和还原型抗坏血酸(AsA)含量显著上升,脱氢抗坏血酸(DHA)含量上升但未达到显著水平,抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)活性和脱氢抗坏血酸还原酶(DHAR)活性显著上升,而GSH和氧化型谷胱甘肽(GSSG)含量下降,AsA/(AsA+DHA)和GSH/(GSH+GSSG)比值降低,谷胱甘肽过氧化物酶(GPX)活性显著降低。本研究为阐明镉胁迫对富硒土壤柑橘的生理影响机制提供了理论依据。     

Inhibitory effect on activator protein-1, nuclear factor-kappaB, and cell transformation by extracts of strawberries (Fragaria x ananassa Duch.)

The inhibitory effects of strawberry (Fragaria x ananassa Duch.) antioxidant enzymes on tetradecanoylphorbol-13-acetate (TPA) or ultraviolet-B (UVB) induced activator protein-1 (AP-1) and nuclear factor-kappaB (NF-kappaB) were studied. The inhibitory effects of strawberry extracts on the proliferation and transformation of human and mouse cancer cells were also evaluated. Strawberries had high activities of glutathione peroxidase, superoxide dismutase, guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase. Strawberry extracts inhibited the proliferation of human lung epithelial cancer cell line A549 and decreased TPA-induced neoplastic transformation of JB6 P+ mouse epidermal cells. Pretreatment of JB6 P+ mouse epidermal cells with strawberry extract resulted in the inhibition of both UVB- and TPA-induced AP-1 and NF-kappaB transactivation. Furthermore, strawberry extract also blocked TPA-induced phosphorylation of extracellular signal-regulated kinases (ERKs) and UVB-induced phosphorylation of ERKs and JNK kinase in JB6 P+ mouse epidermal cell culture. These results suggest that the ability of strawberries to block UVB- and TPA-induced AP-1 and NF-kappaB activation may be due to their antioxidant properties and their ability to reduce oxidative stress. The oxidative events that regulate AP-1 and NF-kappaB transactivation can be important molecular targets for cancer prevention. The strawberries may be highly effective as a chemopreventive agent that acts by targeting the down-regulation of AP-1 and NF-kappaB activities, blocking MAPK signaling, and suppressing cancer cell proliferation and transformation.     

Effect of tea catechins on regulation of antioxidant enzyme expression in H2O2-induced skeletal muscle cells of goat in vitro

Skeletal muscle cells (SMCs) of goats were stress induced with 1 mM H(2)O(2) in the absence or presence of 0.5, 5, and 50 μg/mL tea catechins (TCs) incubation. Cells were harvested at 48 h postincubation with TCs to investigate the effects of TCs on cell proliferation, cell membrane integrity, antioxidant enzyme activities, and antioxidant enzyme genes and protein expression levels. Results showed that H(2)O(2) induction inhibited cell proliferation with or without TC incubation; moreover, the inhibition effect was enhanced in the presence of TCs (P < 0.001). H(2)O(2)-induced stress increased the lactate dehydrogenase (LDH) activity in the absence or presence of TC incubation, but concentrations of TCs, less than 5 μg/mL, showed protective functions against LDH leakage than in other H(2)O(2)-induced treatments. The catalase (CAT) activity increased when SMCs were stress induced with H(2)O(2) in the absence or presence of TC incubation (P < 0.001). H(2)O(2)-induced stress decreased CuZn superoxide dismutase (CuZn-SOD) and glutathione peroxidase (GPx) activities, whereas this effect was prevented by incubation with TCs in a concentration-dependent manner. H(2)O(2)-induced stress with or without TC incubation had significant effects on mRNA and protein expression levels of CAT, CuZn-SOD, and GPx (P < 0.001). CAT and CuZn-SOD mRNA expression levels were increased by different concentrations of TC incubation, and this tendency was basically consistent with corresponding protein expression levels. The GPx mRNA expression level increased with a low concentration of TCs but decreased with concentrations greater than 5 μg/mL of TCs, whereas GPx protein expression in all TC-incubated groups was lower than in the control treatment. The current findings imply that TCs had an inhibitory effect on cell proliferation and enhanced damage to the cell membrane integrity, but TCs affected antioxidant status in SMCs by modulating antioxidant enzyme activities at mRNA and protein expression levels.     

岩藻黄质对人红白血病HEL细胞的凋亡作用及其机制

为探讨岩藻黄质对人红白血病HEL细胞株增殖抑制作用及其诱导凋亡机制,以岩藻黄质处理人红白血病细胞(HEL细胞),采用四甲基偶氮唑蓝(MTT)法检测细胞增殖,流式细胞仪检测细胞凋亡率,分析细胞周期,测定细胞线粒体膜电位,并应用实时荧光定量PCR(RT-qPCR)和Western blot法检测凋亡相关基因及蛋白表达的变化。结果表明,岩藻黄质呈剂量依赖性抑制HEL细胞增殖(P<0.01)。流式细胞术检测显示,岩藻黄质作用24 h后,HEL细胞早期和晚期凋亡的比率极显著增高(P<0.01),G₀/G₁细胞比例增多,S期和G₂/M期细胞比例减少,线粒体膜电位降低;岩藻黄质通过上调促凋亡基因和下调抑凋亡基因的表达引起细胞的凋亡,Bcl-xL蛋白的表达变化不显著(P >0.05),Bcl-2蛋白的表达下调,Caspase-3和Bax蛋白的表达极显著上调(P<0.01)。由此可见,岩藻黄质能诱导HEL细胞凋亡,这为新型抗白血病功能食品的开发及白血病的治疗提供了理论依据。     

玉米铬毒性研究：氧化损伤、渗透调节物质积累、抗氧化防御以及铬的吸收

Agricultural production systems are immensely exposed to different environmental stresses in which heavy metal stress receives serious concerns. This study was conducted to explore the deleterious effects of different chromium(Cr) stress levels, i.e., 0, 30, 6090, 120, and 150 μmol L-1, on two maize genotypes, Wandan 13 and Runnong 35. Both genotypes were evaluated by measuring their growth and yield characteristics, Cr accumulation in different plant tissues, alterations in osmolyte accumulation, generation o reactive oxygen species(ROS), and anti-oxidative enzyme activity to scavenge ROS. The results showed that Cr stress decreased the leaf area, cob formation, 100-grain weight, shoot fresh biomass, and yield formation, while Cr accumulation in different maize tissues was found in the order of roots leaves stem seeds in both genotypes. The increased Cr toxicity resulted in higher free proline soluble sugars and total phenolic contents, and lower soluble protein contents. However, enhanced lipid peroxidation was noticed in the forms of malondialdehyde, hydrogen peroxide(H2O2) and thiobarbituric acid reactive substance accumulation, and electrolyte leakage. The hyperactivity of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, especially glutathione peroxidase and glutathione reductase indicated that these anti-oxidative enzymes had a central role in protecting maize from Cr toxicity, especially for Wandan 13. Moreover, higher uptake and less translocation of Cr contents into the grains of Wandan 13 implied its importance as a potential candidate against soil Cr pollution.     

海藻酸钠寡糖提高水稻幼苗对镉胁迫的抗性

通过水培试验,研究了海藻酸钠寡糖对水稻镉(Cd)毒害的缓解效果,并从Cd的吸收分布、非蛋白巯基(NPT)含量和抗氧化酶活性等方面,初步探讨了其可能的生理机制。结果表明,海藻酸钠寡糖预处理一定程度上可缓解水稻Cd毒害,其中20 mg/L处理的效果较明显,表现为促进了幼苗生长,提高了光合色素含量。进一步分析显示,海藻酸钠寡糖处理的水稻地上部和地下部Cd含量及转移效率均显著降低,Cd在根部细胞壁中的含量及所占比例则显著增加,叶片和根中NPT含量也分别提高了23.5%和14.9%,植物螯合肽(PCs)含量分别增加28.0%和15.0%,抗氧化酶活性和脯氨酸含量也有不同程度提高,丙二醛含量显著下降27.1%。这些结果初步说明细胞壁固持、巯基分子螯合和抗氧化系统均参与了海藻酸钠寡糖对水稻Cd毒害的缓解。     

Berry phenolic extracts modulate the expression of p21(WAF1) and Bax but not Bcl-2 in HT-29 colon cancer cells

Previous studies have shown that anthocyanin-rich berry extracts inhibit the growth of cancer cells in vitro. The objective of this study was to compare the effects of berry extracts containing different phenolic profiles on cell viability and expression of markers of cell proliferation and apoptosis in human colon cancer HT-29 cells. Berry extracts were prepared with methanol extraction, and contents of the main phenolic compounds were analyzed using HPLC. Anthocyanins were the predominant phenolic compounds in bilberry, black currant, and lingonberry extracts and ellagitannins in cloudberry extract, whereas both were present in raspberry and strawberry extracts. Cells were exposed to 0-60 mg/mL of extracts, and the cell growth inhibition was determined after 24 h. The degree of cell growth inhibition was as follows: bilberry > black currant > cloudberry > lingonberry > raspberry > strawberry. A 14-fold increase in the expression of p21WAF1, an inhibitor of cell proliferation and a member of the cyclin kinase inhibitors, was seen in cells exposed to cloudberry extract compared to other berry treatments (2.7-7-fold increase). The pro-apoptosis marker, Bax, was increased 1.3-fold only in cloudberry- and bilberry-treated cells, whereas the pro-survival marker, Bcl-2, was detected only in control cells. The results demonstrate that berry extracts inhibit cancer cell proliferation mainly via the p21WAF1 pathway. Cloudberry, despite its very low anthocyanin content, was a potent inhibitor of cell proliferation. Therefore, it is concluded that, in addition to anthocyanins, also other phenolic or nonphenolic phytochemicals are responsible for the antiproliferative activity of berries.     

不同磁场环境和培养基对拟南芥种子诱导愈伤组织的影响

为探明磁场强度和培养基成份在拟南芥愈伤组织诱导中的作用,以野生型拟南芥(Columbia型)种子为材料,研究3种磁场环境(亚磁场、地磁场和中强磁场)、4种诱导培养基(NB1、NB2、MS1、MS2)条件下愈伤组织的诱导情况。结果显示,与地磁场相比,亚磁场对接种后第3～6天愈伤组织的发生有明显的抑制作用,中强磁场有明显的促进作用;在接种后第3～7天,NB2、MS2比NB1、MS1培养基促进了愈伤组织形成,且差异显著。愈伤组织净重反映了细胞增殖的状态,统计结果显示,与地磁场相比,亚磁场对细胞增殖没有明显影响,而中强磁场有显著的抑制作用;NB2、MS2比NB1、MS1培养基促进了细胞增殖,且差异显著。以上试验结果说明,磁场强度和培养基成份的变化对拟南芥种子诱导愈伤组织过程中第3～7天的愈伤组织形成和细胞增殖有不同程度影响,但2因素不存在交互作用,且2种因素对15d后的愈伤组织总出愈率无显著影响。6-BA对早期的愈伤组织诱导和细胞增殖均有促进作用,而且在地磁和亚磁场中,添加有6-BA的NB2和MS2培养基所诱导的愈伤组织色泽鲜亮,致密度适中,利于后续继代培养。     

接种单细胞微生物对土壤团聚体形成及其稳定性的影响

将根瘤菌(Rhizobium sp.) G-01、肠杆菌(Enterobacter sp.) San8及粘红酵母(Rhodotorula mucilaginosa) R1等3株产胞外多聚物(Extracellular polymeric substances,EPS)的单细胞微生物接种于供试土壤,进行土培试验和盆栽黄瓜试验,研究接种微生物及作物根系对土壤团聚体形成、团聚体组成变化的影响。结果表明,3株单细胞微生物分泌EPS的量分别为2.12 mg (10¹⁰ cells)^-1、0.56 mg (10¹⁰ cells)^-1、172.71 mg (10¹⁰ cells)^-1,其主要组分是多糖、其次是蛋白质,且含有羟基、羧基、羰基等官能团;土培试验后,接种产EPS单细胞微生物处理土壤的大团聚体(>0.25 mm)含量比接种丝状微生物处理提高了71.31%,而盆栽试验后各处理土壤的大团聚体含量(>0.25 mm)比土培试验后土壤显著增加,这可能是由于植...     

Cd胁迫下绿豆和箭舌豌豆叶片抗氧化系统的变化

研究了Cd胁迫下绿豆（Phaseolus aureus）和箭舌豌豆（Vicia sativa）幼苗的生长,叶片内过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）、超氧化岐化酶（SOD）、愈创木酚过氧化物酶（GPOD）和谷胱甘肽还原酶（GR）的同工酶活性,还原性谷胱甘肽（GSH）和抗坏血酸（ASC）以及Cd含量的变化。结果显示,100μmol.L-1Cd胁迫9d期间,随着Cd胁迫时间的延长,绿豆和箭舌豌豆幼苗主根的伸长量和其根系干重显著降低（P〈0.05）,根表面出现越来越明显的褐色,绿豆叶表面出现可见的褐色斑点;两种植物叶片的CAT、APX和SOD同工酶活性以及绿豆叶片的GR活性呈先升后降的趋势,而两种植物叶的GPOD活性明显增加;在箭舌豌豆叶片中,GR活性随Cd暴露时间的延长而增加,而GSH先降后升;在绿豆叶片中,GSH和ASC随Cd暴露时间的延长而降低;与此同时,两种植物叶片中Cd的含量也随Cd胁迫时间的延长而增加,和箭舌豌豆相比,绿豆叶片中Cd含量增加更多。结果表明,箭舌豌豆有较强的抗氧化能力。     

盐胁迫条件下硒对小白菜抗氧化活性及膜脂过氧化作用的影响

采用土培试验的方法研究了盐胁迫条件下硒对小白菜抗氧化活性及膜脂过氧化作用的影响。结果表明,盐胁迫条件下,硒对小白菜的生物量没有显著影响。硒能显著提高小白菜叶片的谷胱甘肽过氧化物酶、过氧化氢酶、过氧化物酶、超氧化物歧化酶的活性以及还原型谷胱甘肽的含量和硒含量,抗氧化活性显著增强。硒显著降低小白菜体内氧自由基和丙二醛的含量;降低了膜脂过氧化作用,抑制小白菜质膜透性的升高。土壤施硒0.9 mg/kg,可提高小白菜对盐分胁迫的适应能力。     

O_3污染胁迫下冬小麦的伤害症状及其对叶片氮代谢脯氨酸和谷胱甘肽含量的影响

采用开顶式气室模拟研究O3污染胁迫对冬小麦叶片可见伤害症状、氮代谢、脯氨酸和谷胱甘肽含量的影响,结果表明冬小麦在O3胁迫下表现出明显的受害症状,且O3浓度越高受害症状越严重。O3浓度升高导致不同生长期冬小麦叶片硝酸还原酶活性显著降低,当O3浓度为40～120 nL.L-1时,拔节期、抽穗期和乳熟期的叶片硝酸还原酶活性分别比对照处理降低45.4%～92.9%、58.0%～93.5%和90.0%～93.2%。O3污染胁迫对冬小麦叶片硝态氮和铵态氮含量也有影响,但是随着O3浓度、冬小麦生长期的不同影响不一样;冬小麦叶片脯氨酸和谷胱甘肽含量在O3污染胁迫下变化也各异。在冬小麦抽穗期,当O3浓度为40、80 nL.L-1时,脯氨酸含量分别比对照处理提高163.9%和173.2%,但是在O3浓度为120 nL.L-1时却降低42.4%。O3污染胁迫下拔节期冬小麦叶片还原型谷胱甘肽（GSH）含量显著比对照处理增加,而抽穗期GSH含量在较高O3浓度胁迫下却显著地比对照处理降低,说明植物在O3胁迫下表现出不同的调节和适应机制。     

Foliar application of zinc promotes cadmium absorption by increasing expression of cadmium transporter genes and activities of antioxidative enzymes in winter wheat

Cadmium (Cd) is a deleterious non-essential metal in plants.To elucidate the mechanisms by which zinc (Zn) application alleviates cadmium (Cd)toxicity in wheat,we characterized plant growth,antioxidant system,leaf cell ultrastructure,and Cd transporter gene expression in winter wheat under Cd exposure (50μmol L^-1Cd) with foliar Zn application in a hydroponic experiment.Results showed that Zn addition (Zn+Cd) or pretreatment (pre-Zn+Cd) at 2 g L^-1as Zn SO₄·7H_...     

Alkyl hydroxytyrosyl ethers show protective effects against oxidative stress in HepG2 cells

Alkyl hydroxytyrosyl ethers (methyl, ethyl, propyl, and butyl ethers) have been synthesized from hydroxytyrosol (HTy) in response to the increasing food industry demand of new lipophilic antioxidants. Having confirmed that these compounds reach portal blood partially unconjugated and thus are effectively absorbed, their potential antioxidant activity was evaluated in the human hepatocarcinoma cell line (HepG2). The effects of 0.5-10 μM alkyl hydroxytyrosyl ethers on HepG2 cell integrity and redox status were assessed as well as the protective effect against oxidative stress induced by tert-butylhydroperoxide (t-BOOH). Cell viability (Crystal violet) and cell proliferation (BrdU assay) were measured as markers of cell integrity, concentration of reduced glutathione (GSH), generation of reactive oxygen species (ROS), and activity of antioxidant enzymes glutathione peroxidase (GPx) and glutathione reductase (GR) as markers of redox status and determination of malondialdehyde (MDA) as a marker of lipid peroxidation. Direct treatment of HepG2 with alkyl hydroxytyrosyl ethers induced slight changes in cellular intrinsic antioxidants status, reducing ROS generation and inducing changes in GPx and GR activities. Pretreatment of HepG2 cells with alkyl hydroxytyrosyl ethers counteracted cell damage induced by t-BOOH, partially after 2 h and completely after 20 h, by increasing GSH and decreasing ROS generation, MDA levels, and antioxidant enzyme (GPx and GR) activity. According to these results the alkyl hydroxytyrosyl ethers show clear protective effects against oxidative stress, related to their lipophilic nature, that are similar to or even higher than those of their precursor, HTy.     

Molecular mechanisms of (-)-epicatechin and chlorogenic acid on the regulation of the apoptotic and survival/proliferation pathways in a human hepatoma cell line

Dietary polyphenols have been associated with reduced risk of chronic diseases, but the precise molecular mechanisms of protection remain unclear. This work was aimed at studying the effect of (-)-epicatechin (EC) and chlorogenic acid (CGA) on the regulation of apoptotic and survival/proliferation pathways in a human hepatoma cell line (HepG2). EC or CGA treatment for 18 h had a slight effect on cell viability and decreased reactive oxygen species formation, and EC alone promoted cell proliferation, whereas CGA increased glutathione levels. Phenols neither induced the caspase cascade for apoptosis nor affected expression levels of Bcl-xL or Bax. A sustained activation of the major survival signals AKT/PI-3-kinase and ERK was shown in EC-treated cells, rather than in CGA-exposed cells. These data suggest that EC and CGA have no effect on apoptosis and enhance the intrinsic cellular tolerance against oxidative insults either by activating survival/proliferation pathways or by increasing antioxidant potential in HepG2.     

外源乙烯对镉处理下玉米幼苗生理代谢的影响

为探讨外源乙烯缓解玉米（Zea mays）幼苗镉（Cd）毒害的生理机制,通过水培试验研究了Cd处理下,外源乙烯对玉米幼苗相关生理指标与Cd的亚细胞分布的影响,以不做任何处理为空白对照,以Cd处理和（NH₄）₂SO₄处理为试验对照。结果显示,相对Cd处理,乙烯和（NH₄）₂SO₄处理可显著降低Cd胁迫下玉米幼苗H₂O₂和丙二醛（MDA）含量,使净光合速率分别提升1.23倍和1.22倍;显著降低抗氧化物酶[超氧化物歧化酶（SOD）、过氧化氢酶（CAT）]活性,抗氧化物质[抗坏血酸（AsA）、谷胱甘肽（GSH）]含量则显著上升。另外,相对于Cd处理,乙烯+Cd处理可使玉米幼苗ATP硫酸化酶活性、谷胱甘肽还原酶（GR）活性、半胱氨酸和还原型谷胱甘肽（GSH）含量分别上升54.43%、27.93%、50.77%和49.85%,而对非蛋白硫醇（NPT）和植物螯合素（PCs）含量无显著性影响。在乙烯+Cd处理的基础上添加GSH合成抑制剂BSO（buthionine sulfoximine）可导致玉米叶片GSH含量显著降低,H₂O₂含量上升,光合速率下降。外源乙烯可显著降低Cd胁迫下玉米叶片Cd含量,而显著提升根部细胞壁和液泡中Cd含量。因此,外源乙烯一方面通过提升玉米叶片GSH和AsA含量,增强叶片非酶促抗氧化能力,而非通过抗氧化酶促反应和NPT、PCs的螯合作用;另一方面则通过根细胞壁的固定作用和液泡区室化作用,减少Cd向玉米叶片中的转移,从而缓解Cd毒害。研究结果可为乙烯作为潜在的作物重金属拮抗剂提供理论依据。