Responses of the antioxidant system to fluroxypyr in foxtail millet (Setaria italica L.) at the seedling stage

Foxtail millet(Setaria italica L.) is an important food and fodder crop in semi-arid areas. However, there are few herbicides suitable for use on weed control in field-grown foxtail millet during the post-emergence herbicides stage. The present study was conducted using four concentrations(0.5, 1, 2, and 4 L ai ha–1) of foliar-applied fluroxypyr, and the effect of fluroxypyr on selected metabolic and stress-related parameters in foxtail millet were assessed after 15 days. In this study, increasing concentrations decreased plant height and accumulation of chlorophylls. Our results also showed that malondialdehyde(MDA) accumulated in response to fluroxypyr application, demonstrating increased lipid peroxidation due to excessive reactive oxygen species production. In response to this oxidative stress, the activities of antioxidant enzymes were generally enhanced. Non-enzymatic antioxidant defense systems, which function in concert with antioxidant enzymes, can also protect plant cells from oxidative damage by scavenging reactive oxygen species(ROS). In conclusion, the hybrid variety(Zhangzagu) exhibited a greater tolerance to fluroxypyr than did the conventional variety Jingu 21, which might be associated with the antioxidant mechanisms of Zhangzagu hybrid millet.     

外源一氧化氮对苯丙烯酸胁迫下黄瓜幼苗生长及活性氧代谢的影响

【目的】苯丙烯酸是黄瓜根系分泌的毒性较大的酚酸类物质之一,与黄瓜的连作障碍有密切关系。研究外源一氧化氮对苯丙烯酸胁迫下黄瓜幼苗生长及活性氧代谢的缓解作用,初步探讨NO缓解黄瓜幼苗苯丙烯酸胁迫的生理机制。【方法】采用营养钵土培的方法,研究外源一氧化氮(nitric oxide,NO)对200μmol·L-1苯丙烯酸胁迫下黄瓜(Cucumis sativus L.)幼苗生长、抗氧化酶系统和活性氧代谢的影响。【结果】100μmol·L-1NO供体硝普钠(sodium nitroprusside,SNP)能显著缓解苯丙烯酸胁迫对黄瓜植株造成的伤害,可明显提高幼苗的生长量,增强叶片的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性,提高叶片叶绿素和脯氨酸(Pro)含量,降低了叶片丙二醛(MDA)、过氧化氢(H2O2)含量和超氧阴离子(产生速率。与100μmol·L-1SNP处理相比,50、200和400μmol·L-1SNP处理促进黄瓜幼苗生长、缓解叶片氧化损伤和提高抗氧化酶的活性的作用明显降低。【结论】外源NO能明显促进了苯丙烯酸胁迫下黄瓜幼苗的生长,提高了抗氧化酶活性,降低了活性氧代谢,其中以100μmol·L-1SNP缓解效果最好。因此认为,外源NO的确能缓解苯丙烯酸胁迫对黄瓜植株的伤害,提高黄瓜幼苗对苯丙烯酸胁迫的耐性,减缓因自毒作用引起的连作障碍。     

施氮量对烤烟烟叶抗氧化系统及质量的影响

[目的]研究施氮量对烤烟烟叶抗氧化系统及质量的影响。[方法]以K326为试验材料,对不同施氮水平烤烟生长成熟期间烟叶活性氧含量、SOD活性、GR活性、APX活性、抗氧化剂含量、化学成分进行了研究。[结果]随着烟叶在田间的生长成熟,烟叶内超氧阴离子产生速率、过氧化氢的含量呈增加趋势;抗氧化酶活性整体呈先上升后下降的趋势;抗氧化剂GSH逐渐下降;As A含量在生长前期逐渐增加,但生长后期逐渐下降。不同施氮水平对烤烟烟叶生长成熟期间抗氧化系统有显著影响。在高氮水平下,烟叶内活性氧清除系统中的自由基清除剂(GSH、As A)和相关酶活性(SOD、GR、APX)均显著或极显著高于低氮水平处理。随着施氮量的增加,烤后烟叶含氮化合物显著增高,蛋白质、淀粉、叶绿素和类胡萝卜素等大分子物质降解量减少,石油醚提取物显著减少,但对钾和氯影响不显著,烟叶质量降低。[结论]烤烟大田管理中适量施氮(45.0 kg/hm2)有利于烟叶生长前期保持较高抗氧化活性,抵御胁迫,在成熟期确保适时成熟,提高烟叶质量。     

Mechanisms involved in biocontrol and plant induced resistance by richoderma. asperellum (T. harzianum T-203)

Growing awareness of the environmental damage caused by the use of chemical substances for plant disease control in agriculture has raised the need to study biological alternatives, such as activating the defense response of plant crops by inducers not toxic to the environment. Trichoderma spp. are effective biocontrol agents for a number of soilborne pathogens, and are also known for their ability to enhance plant growth and to induce systemic resistance (ISR) in plants. In our laborator…     

外源硫化氢缓解水稻盐胁迫的作用机理

为探明外源H_2S缓解水稻盐胁迫的作用机理,以水稻日本晴为材料,在水培条件下,研究H_2S对NaCl胁迫下5叶期水稻幼苗生长与活性氧(ROS)代谢和抗氧化酶系统的影响。结果表明:100mmol/L NaCl处理严重抑制水稻幼苗的生长,诱导ROS的产生,造成氧化损伤;盐胁迫下添加抗氧化酶抑制剂(二乙基二硫代氨基甲酸钠DDC或3-氨基-1,2,4-三唑AT),活性氧(ROS)得不到及时有效分解而高水平累积,加剧了氧化胁迫对植物的伤害;在盐胁迫条件下添加100μmol/L NaHS(外源H_2S供体)处理,能显著增加叶片内H_2S水平,加快活性氧的清除,从而减轻盐胁迫下的膜脂过氧化程度,促进植物生长。H_2S具有抗氧化作用,外施H_2S可提高植物耐盐性。     

Beneficial role of melatonin in protecting mammalian gametes and embryos from oxidative damage

Mammalian gametes and embryos are particularly vulnerable to oxidative stress-induced damage, which is mainly caused by reactive oxygen species (ROS) originating from normal metabolism and/or the external environment. Several researchers have implicated the role of oxidative stress in the activation of apoptosis, causing peroxidative damage to sperms/oocytes and inducing embryo fragmentation, arrest, or demise. Melatonin is a tryptophan derivative that is known for its powerful free radical-scavenging activity and broad-spectrum antioxidant property. Numerous studies have shown that melatonin and its metabolic derivatives can sequentially detoxify ROS in an antioxidant cascade, and modulate various antioxidant enzymes via its receptors to prevent radical-mediated damage. The identification of melatonin receptors in cumulus/granulosa cells, oocytes, and epididymal tissues implies that melatonin has protective actions on gametes and embryos. Enriching the semen extender or culture medium with melatonin significantly benefits sperm characteristics, improves oocyte maturation potential and quality, and enhances the developmental competence of preimplantation embryos. Certainly, further comparative studies are needed to show the unique antioxidant role and the advantage of melatonin in this field. This review summarizes the harmful effects of ROS and the beneficial role of melatonin against oxidative damage of gametes and embryos.     

Growth,photosynthetic efficiency and metabolic alterations associated with exogenous hydrogen peroxide in <Emphasis Type="Italic">Artemisia annua</Emphasis>: Overproduction of artemisinin

Artemisinin, a sesquiterpene lactone with a peroxide linkage, has been held responsible for antimalarial activity of the Artemisia annua L. Recently, it was reported that reactive oxygen species (ROS) play important role in the biosynthesis of artemisinin by catalyzing some important intermediate steps. The effect of exogenously supplied hydrogen peroxide (1.00 mM and 2.00 mM H₂O₂), in two ways, foliar and as soil drench, was worked out in terms of growth, alteration in photosynthesis, oxidative damage, antioxidant defense enzymes and artemisinin level in exposed plants. Application of H₂O₂ positively affect the growth of the treated plants; and increment in net photo synthetic rate, stomatal conductance, internal CO₂ and chlorophyll content in the H₂O₂ exposed A. annua plants was noted. A significant upregulation in antioxidant enzymes viz. catalase (CAT), peroxidase (POX) and superoxide dismutase (SOD) was observed as a result of exogenous H₂O₂ treatment when applied foliarly or as soil drench. H₂O₂application either by 1.00 mM or 2.00 mM stimulated artemisinin levels, however, 2.00 mM H₂O₂ applied as soil drench elicited artemisinin production more rapidly compared to other treatments. Therefore, results suggest that exogenous H₂O₂ may stimulate growth by inducing antioxidant defense system and increase the artemisinin levels in Artemisia annua plants.     

渗透胁迫对植物抗氧化酶影响的研究进展

植物在受到渗透胁迫后会产生活性氧基团等有害物质,活性氧能够导致蛋白质、膜脂、DNA及其他细胞组分的严重损伤。因此,活性氧的清除对于维持植物正常的功能具有重要意义。启动抗氧化防御系统是植物免受渗透胁迫伤害的主要防御机制之一。综述了渗透胁迫对超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）这3种抗氧化酶及其基因表达的影响。     

冷蒿抗氧化防御系统对机械损伤的响应

放牧对草地植物的直接影响包括动物的采食和践踏。为了探讨冷蒿Artemisia frigida的耐牧性,采用人工机械损伤(轻度、中度和重度)的方式处理盆栽冷蒿地上枝叶,分别测定冷蒿叶片和根系活性氧(ROS),丙二醛(MDA),抗坏血酸(AsA)和谷胱甘肽(GSH)质量摩尔浓度,同时测定了抗氧化防御酶和抗坏血酸(AsA)-谷胱甘肽(GSH)循环酶活性的变化。结果表明:随着机械损伤强度的增加,冷蒿叶片超氧阴离子(O₂·-)和过氧化氢(H₂O₂)质量摩尔浓度升高,膜质过氧化增强;超氧化物歧化酶(SOD),过氧化氢酶(CAT)和过氧化物酶(POD)活性随机械损伤强度的增加而升高。在轻度和中度处理下,冷蒿叶片中抗坏血酸过氧化物酶(APX),脱氢抗坏血酸还原酶(DHAR),单脱径抗坏血酸还原并(MDHAR)和谷胱甘肽还原酶(GR)活性增强,抗氧化剂(AsA和GSH)的还原力(ρ_AsA/ρ_DHA值和ρ_GSH/ρ_GSSG值)处于稳定平衡状态;重度机械损伤下AsA-GSH循环效率显著降低(P≤0.05)。冷蒿根系抗氧化防御系统对机械损伤也表现出明显的应激反应能力。综上所述,机械损伤使冷蒿体内ROS质量摩尔浓度升高,且冷蒿能够在不同程度的机械损伤下快速、有效地启动体内抗氧化防御系统,清除体内过量的ROS,维持一定的AsA-GSH循环效率,表现出较强的耐损伤能力。图4表1参42     

水杨酸调控作物耐盐性生理机制

盐胁迫严重限制作物生长和产量。水杨酸是一种植物激素,对植物生长发育和抵御逆境胁迫具有重要作用。文章综述植物体内水杨酸合成代谢途径,水杨酸有效性影响因素及调控作物耐盐生理机制,包括诱导抗氧化防御系统,降低膜脂过氧化;促进光合和呼吸作用;调控离子吸收与分布,缓解离子毒害;调控物质代谢,改善营养状况;与其他激素或信号物质间交叉对话。同时提出相关领域研究重点。     

Mechanisms involved in biocontrol and plant induced resistance by Trichoderma asperellum（ T. harzianum T-203）

Growing awareness of the environmental damage caused by the use of chemical substances for plant disease control in agriculture has raised the need to study biological alternatives, such as activating the defense response of plant crops by inducers not toxic to the environment. Trichoderma spp. are effective biocontrol agents for a number of soilborne pathogens, and are also known for their ability to enhance plant growth and to induce systemic resistance (ISR) in plants.     

Mechanisms involved in biocontrol and plant induced resistance by Trichoderna asperellun (T. harzianum T-203)

Growing awareness of the environmental damage caused by the use of chemical substances for plant disease control in agriculture has raised the need to study biological alternatives, such as activating the defense response of plant crops by inducers not toxic to the environment. Trichoderna spp. are effective biocontrol agents for a number of soilborne pathogens, and are also known for their ability to enhance plant growth and to induce systemic resistance (ISR) in plants.     

植物体内活性氧代谢及其信号传导

活性氧是植物体内一类化学性质很活泼、氧化能力很强的含氧物质的总称。它们能对机体细胞造成氧化损伤，但同时在各种防卫反应中起着积极的作用，概述了近年来植物体内活性氧代谢及其信号传导取得的研究成果。     

高温干旱胁迫对黄薇抗氧化防御系统的影响

黄薇Heimia myrtifolia是具有较高价值的引种植物,但对其引种后的适应性研究仍较缺乏。为了探究黄薇对高温干旱及协同胁迫的响应,采用人工模拟自然状态下干旱（对照、轻度干旱、中度干旱和重度干旱）,高温（30,36和42℃）及高温干旱协同胁迫对黄薇叶片抗氧化防御系统的影响。结果显示:干旱胁迫下,过氧化物酶（POD）活性和丙二醛（MDA）质量摩尔浓度显著增加（P < 0.05）,脂膜过氧化程度加深,抗坏血酸-谷胱甘肽（AsA-GSH）循环相关酶活性和相关还原物质均呈先上升后下降趋势,在中度胁迫下达到顶峰,与对照相比均显著增加（P < 0.05）。高温胁迫下,抗氧化酶效率和AsA-GSH循环效率均有提高。高温干旱协同胁迫下,黄薇受到的伤害明显大于单一胁迫,超氧化物歧化酶（SOD）和POD显著上升（P < 0.05）并于中度胁迫时达到顶峰,MDA质量摩尔浓度显著增加（P < 0.05）,AsA-GSH循环效率均有提高但在中度胁迫下开始下降,脂膜过氧化随着胁迫加深显著加剧,重度胁迫下已无法维持正常生长。黄薇在高温干旱胁迫下可以通过调节抗氧化酶系统和AsA-GSH循环共同清除氧化物质,提高抗胁迫能力,维持正常生长发育。     

稀土Y3+对铜绿微囊藻生长及其抗氧化酶活性的影响

为探讨钇(Y3+)质量浓度对铜绿微囊藻(Microcystis aeruginosa)的生长及其抗氧化酶含量变化的影响,以铜绿微囊藻FACHB912为试材,研究了不同质量浓度的外源稀土Y3+对藻细胞生长、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性、丙二醛(MDA)含量的影响.结果表明,低质...     

硒减轻油菜幼苗硼毒害机理的研究

【目的】硼是植物生长发育所必需的微量元素,但在土壤中过量存在会对植物产生毒害。在干旱半干旱地区硼毒害是限制作物生长的重要因子,此外,硼矿开采以及硼肥用量过大或施用不均匀均会导致硼浓度过高,从而限制作物生长。适量硒能提高作物抗性,减轻作物因逆境产生的伤害,本文旨在通过适量硒处理,研究硒对高硼条件下油菜生物量及油菜活性氧代谢的变化,探讨硒缓解高硼对油菜生长抑制作用的机理,进而提高作物对硼的适宜范围,减轻硼毒害对农业生产的危害。【方法】本文以油菜（湘农油571）为试验材料,设置硼和硒2因素2水平（硼水平为：50、500 μmol•L-1,分别用B50、B500表示,硒水平为：0、1 μmol•L-1,分别用Se0、Se1表示）完全随机试验,共4个处理,通过苗期溶液培养,研究硒对高硼（500 µmol•L-1）胁迫条件下油菜幼苗生长、硼吸收累积和抗氧化酶及非酶系统的影响。【结果】高硼胁迫条件下油菜幼苗地上部和地下部干物质重显著降低,与正常硼（50 μmol•L-1）处理相比分别降低20.1%和32.0%;硼含量和累积量显著增加,与正常硼处理相比分别增加2.95和2.97倍;油菜幼苗因硼毒害导致叶片内抗氧化酶（过氧化氢酶（CAT）、过氧化物酶（POD）和抗坏血酸过氧化物酶（APX））活性和非酶抗氧化物（谷胱甘肽（GSH））含量显著降低,与正常硼处理相比,CAT、POD和APX活性分别降低19.7%、11.0%和15.0%;而过氧化氢（H2O2）和丙二醛（MDA）含量显著增加,比正常硼处理分别增加19.0%和18.5%。高硼条件下,经1 μmol?L-1硒处理,与无硒处理相比,地上部和地下部干物质重分别增加22.8%和28.6%,硼含量和累积量分别降低38.6%和31.9%;油菜幼苗叶片内抗氧化酶活性和非酶抗氧化物含量显著增加,CAT、POD和APX活性分别增加12.8%、15.1%和15.3%,GSH和ASA含量分别增加9.7%和21.0%;而过氧化氢和丙二醛含量分别降低25.1%和21.2%。【结论】适量硒可降低高硼胁迫下油菜幼苗硼的吸收累积,增强抗氧化酶和非酶系统抗氧化作用,降低活性氧累积,减轻细胞质膜因过氧化作用而产生的损伤,从而显著减轻过量硼对油菜生长的影响,提高油菜幼苗对硼过量的适应性。     

Normalization of tumor vasculature: an emerging concept in antiangiogenic therapy

Solid tumors require blood vessels for growth, and many new cancer therapies are directed against the tumor vasculature. The widely held view is that these antiangiogenic therapies should destroy the tumor vasculature, thereby depriving the tumor of oxygen and nutrients. Here, I review emerging evidence supporting an alternative hypothesis-that certain antiangiogenic agents can also transiently "normalize" the abnormal structure and function of tumor vasculature to make it more efficient for oxygen and drug delivery. Drugs that induce vascular normalization can alleviate hypoxia and increase the efficacy of conventional therapies if both are carefully scheduled. A better understanding of the molecular and cellular underpinnings of vascular normalization may ultimately lead to more effective therapies not only for cancer but also for diseases with abnormal vasculature, as well as regenerative medicine, in which the goal is to create and maintain a functionally normal vasculature.     

水分胁迫下水杨酸对大麦幼苗抗氧化能力的影响

水杨酸是一种与植物逆境生理密切相关的生长调节物质.研究选取普通大麦为实验材料,通过不同浓度的外源水杨酸处理,考察其在水分胁迫下对大麦幼苗抗氧化能力的影响.结果表明,水杨酸的作用具有双重性:低浓度的水杨酸(＜0.30 mmol/L)可以改善水分胁迫下大麦幼苗的水分状况,并且降低丙二醛含量,维持较低水平的蛋白质羰基含量,减...