外源NO对NaCl胁迫下辣椒幼苗氧化损伤的保护效应

以辣椒品种陇椒2号为试验材料,研究了外源NO供体硝普钠(SNP)对辣椒幼苗氧化损伤的影响.结果显示,在100 mmol/L NaCl胁迫下,辣椒叶片的MDA含量、质膜相对透性和脯氨酸含量均增加,保护酶SOD、CAT活性降低,而POD活性只在胁迫18 d时降低.0.1 mmol/L SNP处理可减缓NaCl胁迫下辣椒幼苗叶片MDA含量的上升,降低叶片质膜相对透性,并诱导SOD、POD和CAT活性增加,提高脯氨酸含量,表明外源NO可以通过提高盐胁迫下辣椒幼苗叶片组织的抗氧化能力来缓解氧化损伤.而SNP相似物NaNO2和K3Fe(CN)6处理对盐胁迫引起的氧化损伤并没有起到明显的缓解作用,进一步证实了NO对辣椒幼苗耐盐性具有专一性的调节作用.     

外源一氧化氮对铅胁迫下小麦种子萌发及幼苗生理特性的影响

利用室内水培实验,研究了外源一氧化氮（NO）供体硝普钠（SNP）对Pb²⁺处理下小麦（Triticum aestivum L.）种子萌发、幼苗生长及相关生理指标变化的影响。结果表明,Pb²⁺处理使小麦种子发芽势、发芽率、幼苗根长和茎长均显著降低,诱导叶绿素a、叶绿素b含量减少及叶绿素荧光参数F_v/F_m和F_v/F_o的比值减小,25 μmol·L^-1 SNP明显缓解Pb²⁺胁迫对种子萌发及幼苗生长的抑制作用,提高Pb²⁺胁迫下叶绿素a、叶绿素b含量及F_v/F_m和F_v/F_o的比值,而100 μmol·L^-1SNP无明显缓解作用。此外,25和100 μmol·L^-1SNP诱导Pb²⁺胁迫下小麦幼苗叶片过氧化氢酶（CAT）活性增强和可溶性蛋白含量增多,但100 μmol·L^-1SNP处理降低了过氧化物酶（POD）活性。结果说明,外源NO促进Pb²⁺胁迫下小麦种子萌发及幼苗生长,提高叶绿素和可溶性蛋白含量,诱导CAT活性升高,从而增强小麦对Pb²⁺胁迫的适应性。     

Involvement of Nitrate Reductase and Nitric Oxide (NO) in Implementation of the Stress-Protective Action of a Carbon Monoxide (CO) Donor on Wheat Seedlings under Hyperthermy

Russian Journal of Plant Physiology - The involvement of nitric oxide (NO) and its cross-talk with different signal mediators was studied upon the induction of heat-resistance of wheat (Triticum...     

一氧化氮对小麦叶片镍毒害的缓解作用

采用溶液培养法研究了重金属镍(Ni)对扬麦158(Triticum aestivumL)幼苗生长的影响及外源一氧化氮(NO)对Ni毒害的缓解作用。结果表明,100μmol/LNi处理显著抑制小麦幼苗生长,导致叶绿素含量下降,丙二醛(MDA)含量显著升高,且叶片过氧化物酶(POD)、超氧化物歧化酶(SOD)和谷胱甘肽转硫酶(GST)等抗氧化酶活性升高。400μmol/L硝谱钠(SNP,NO供体)预处理2d,能够明显减轻Ni毒害,使叶绿素和MDA含量基本恢复至对照水平。NO可能是通过提高APX和GR等抗氧化酶的活性及谷胱甘肽含量而增强植株抗氧化能力,显著减轻由Ni导致的叶片Ca和Fe含量下降而增强小麦幼苗抵御Ni毒害的能力。     

外源NO对铜胁迫下番茄幼苗根系构型及其超微结构的影响

采用营养液水培的方法,以“改良毛粉802F1”番茄为材料,硝普钠（sodiumnitroprusside,sNP）为一氧化氮（N0）供体,研究外源N0对铜胁迫下番茄幼苗根系构型及其超微结构的影响。结果表明,50μmol·L-1的铜胁迫下,外施100μmol·L-1 SNP能够显著增加番茄幼苗植株的生物量、株高和茎粗,提高根系活力,改善根系构型中的根长度、根平均直径、根表面积和根体积,缓解番茄幼苗亚细胞结构（细胞核、线粒体、叶绿体、液泡、核膜）的改变,维持番茄幼苗组织结构的稳定,减缓铜胁迫对植株生长的抑制作用,添加NO清除剂牛血红蛋白后,能显著消除NO的缓解效果。     

Role of NO Synthesis Modification in the Protective Effect of Putrescine in Wheat Seedlings Subjected to Heat Stress

Applied Biochemistry and Microbiology - The role of nitric oxide and its functional relations to reactive oxygen species (ROS) and calcium are studied in relation to the stress-protective effects...     

外源NO提高小麦幼苗抗旱性的生理机制

以小麦(Triticum aestivum L.)品种'豫麦49'为材料,采用50μmol·L-1SNP(NO供体)处理自然干旱和PEG模拟干旱下的小麦幼苗,分析外源NO对水分胁迫下小麦幼苗相对含水量、光合速率、细胞膜透性以及茎叶中关键性离子含量的影响.结果显示:自然干旱10 d后,对照组幼苗几乎全部枯死,而50μmol·L-1SNP处理幼苗并未发生枯死,其幼苗在旱后复水2 d后能完全恢复正常生长;在25%PEG-6000模拟干旱条件下,50μmol·L-1SNP处理也能明显改善受胁迫小麦幼苗长势.50μmol·L-1SNP处理使模拟干旱胁迫下小麦叶片的相对含水量显著提高15.98%,净光合速率(Pn)、气孔导度(Gs)分别显著提高47.11%和42.86%,而胞间CO2浓度(GI)显著降低了8.19%;也使小麦组织浸出液电导率显著降低30%,茎叶的K 含量显著增加24.55%(P<0.01).研究发现,外源NO既可通过降低小麦幼苗叶片蒸腾来维持较高的叶片相对含水量,缓解因干旱缺水对植株的伤害;又可增加K 在茎叶中积累,减轻干旱胁迫对小麦幼苗细胞膜伤害,维持干旱胁迫下小麦幼苗较高的光合速率,以确保植株正常生长和有机物质积累.     

外源一氧化氮对镉胁迫下玉米幼苗根生长及氧化伤害的影响

以玉米幼苗为材料,通过在镉处理的同时补充外源一氧化氮(NO)供体硝普钠(SNP)及其类似物[K3Fe(CN)6]、以及NO消除剂,分析NO对植物耐镉性的影响,探讨NO在植物逆境胁迫响应中的作用及其机理。结果显示:添加20μmol·L-1 SNP能显著降低镉引发的玉米幼苗根生长抑制及根尖内源镉的积累,减少电解质的渗漏以及超氧化物自由基(O2.-)和过氧化氢(H2O2)的上升幅度,抑制超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性的增加,进一步提高镉胁迫下谷胱甘肽还原酶(GR)的活性。SNP的上述效应可被NO消除剂2-(4-羧基-2-苯基)-4,4,5,5-四甲基咪唑-1-氧-3-氧化物(cPTIO)所逆转,而SNP类似物K3Fe(CN)6的应用对上述反应几乎无影响,说明该反应具有NO特异性。研究表明,外源NO能够显著缓解镉胁迫对玉米幼苗生长造成的伤害,该缓解作用主要是通过降低植株体内内源镉积累和减轻镉诱发的氧化伤害来实现的。     

一氧化氮对盐胁迫下小麦幼苗根生长和氧化损伤的影响

0.05和0.10 mmol/L一氧化氮(NO)供体硝普钠(sodium mtropmsside,SNP)处理明显减轻NaCl浓度为150 mmo1/L左右的盐胁迫对小麦幼苗根生长的抑制效应,其中0.05mmol/L的SNP效果最明显;0.30mmol/L以上的SNP处理对根抑制无明显缓解作用;当NaCl浓度大于300 mmol/L时,各种浓度的SNP均不能减轻盐胁迫对根生长的抑制.以N O清除剂血红蛋白(hemoglobin,Hb)以及NOx-,K3Fe(CN)6等为对照,观察到0.05 mmol/L的SNP能不同程度地提高150mmo/L盐胁迫下小麦幼苗根尖细胞中超氧化物歧化酶(SOD)、过氧化物酶(POD)和抗坏血酸过氧化物酶(ascorbateperoxidase,APX)活性,明显降低MDA、H2O2和O2-.的积累,阻断盐胁迫诱导的根尖细胞DNA片段化,表明NO能有效缓解盐胁迫引起的小麦幼苗根尖细胞的氧化损伤.     

DELLA蛋白参与拟南芥幼苗对一氧化氮逆境的抵抗

DELLA蛋白是赤霉素信号途径中的一类对植物生长起抑制作用的重要蛋白质,在拟南芥（Arabidopsis thaliana）基因组中已经鉴定出5个DELLA蛋白基因。目前研究发现,DELLA蛋白在抗逆中也起了重要的作用。近年来,一氧化氮（nitric oxide,NO）的研究工作取得重要进展,低浓度的NO能够促进植物的生长,但在高浓度下它对植物生长起抑制作用甚至导致细胞死亡。通过外施一氧化氮供体硝普钠（sodium nitro prusside,SNP）,研究高浓度NO对拟南芥幼苗生长的影响,发现植物体内H2O2积累,幼苗死亡。通过研究DELLA蛋白基因表达的变化及其相关突变体的表型,证明DELLA蛋白在抵抗NO逆境中起了重要作用。研究结果揭示了DELLA蛋白与NO逆境的关系,为今后科学指导农业生产提供了理论依据。     

Functional Interaction of ROS and Nitric Oxide during Induction of Heat Resistance of Wheat Seedlings by Hydrogen Sulfide Donor

Russian Journal of Plant Physiology - The participation of reactive oxygen species (ROS) and nitric oxide (NO), and also enzymatic systems generating them, in the development of heat resistance of...     

一氧化氮缓解盐胁迫对玉米生长的抑制作用

研究了一氧化氮(nitric oxide,NO)对NaCl 100mmol/L胁迫下玉米幼苗生长的影响.结果表明:0.1～200μmol/L的NO供体硝普钠(sodium nitroprusside,SNP),特别是100μmol/L SNP处理可以显著提高盐胁迫下玉米幼苗的干物质积累速率.100μmol/L的SNP处理还显著提高了叶绿素含量、植株体内K /Na 比和(Spd Spm)/Put的比值,降低膜透性.推测NO对盐胁迫下玉米生长抑制的缓解作用是由于NO促进根系对K 的选择性吸收及其向地上部的运输,而降低对Na 的吸收及其向地上部的运输,并促进Put向Spd和Spm的转化.     

外源NO对铝毒下水稻根系生长和抗氧化系统的影响

以水稻品种‘浙辐802’为材料,采用水培法研究铝毒下外源NO对幼苗根系生长、活性氧产生和抗氧化酶活性的影响,探讨外源NO提高水稻耐铝性的生理生化机制。结果显示:(1)0.05mmol/L Al显著抑制水稻根系生长,促使根尖Al、胼胝质、过氧化氢(H2O2)和超氧阴离子自由基(O-·2)含量显著增加;而外源0.1mmol/L的NO供体亚硝基铁氰化钠(sodium nitroprusside,SNP)预处理能使铝毒下水稻幼苗根相对伸长率及根尖NO含量分别增加34.96%和12.86%,根尖Al和相对胼胝质含量分别下降83.04%和31.93%,表明NO可部分缓解铝毒害,且这种作用与内源NO含量变化有关。(2)外源NO同时使铝毒下水稻幼苗根尖H2O2和O-·2含量分别下降15.43%和12.93%,使超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性显著上升,且外源NO的该种作用可以被0.075mmol/L NO清除剂(carboxy-PTIO,cPTIO)所逆转。研究表明,外源NO在调节活性氧代谢以维持细胞膜结构稳定,进而有效减轻Al对水稻根系的损伤上起着重要作用。     

GABA Requires Nitric Oxide for Alleviating Arsenate Stress in Tomato and Brinjal Seedlings

In recent years, gamma-aminobutyric acid (GABA) and nitric oxide (NO) have drawn much attention in reducing/alleviating metal toxicity in plants. Arsenic is a potentially toxic metal that imposes severe toxic effects on crop plants. Therefore, the present study was an attempt to explore the role of GABA and NO in the amelioration of arsenate As(V) toxicity in tomato and brinjal seedlings. Arsenate toxicity reduced fresh mass about by 17% in tomato and 25% in brinjal seedlings, increased the level of reactive oxygen species, antioxidant enzymes (except glutathione-S-transferase), and altered photosynthesis. However, exogenously applied GABA and sodium nitroprusside (SNP, a NO donor) improved the growth of both vegetables and reduced As(V) toxicity. Interestingly, As(V) toxicity was further increased on applying biosynthetic inhibitor of NO even in the presence of GABA, and under similar conditions addition of NO donor rescued the negative effect of biosynthetic inhibitor (L-NAME) of NO. This indicates that NO is crucial in GABA-mediated alleviation of As(V) toxicity in tomato and brinjal seedlings. Besides this, results revealed that c-PTIO (a NO scavenger) addition reversed the alleviatory effect of SNP also suggesting that NO is important in curtailing As(V) toxicity. Overall, the results indicated that NO is necessary for mitigation of As(V) stress by GABA in two studied vegetable crops but NO itself does not require GABA for the same.

     

Nitric Oxide Alleviates Photochemical Damage Induced by Cadmium Stress in Pea Seedlings

Cadmium (Cd), a life threatening hazardous heavy metal is abundant in nature. Cd amounts are greater in leaves than other plant parts, and it shows considerable effects on photosynthesis. Nitric oxide (NO), a free radical present in living organisms, is now known as an important signaling molecule playing various physiological processes in plants. In this study, the possible ameliorative effect of NO on photosynthesis was examined on pea seedlings grown under Cd stress. Results showed that chlorophyll, net photosynthetic rate, transpiration rate, stomatal conductance, photochemical efficiency of Photosystem II and Photosystem I decreased, and Fo and non-photochemical parameters for PSII and PSI significantly increased due to Cd stress. This suggests that Cd affects the photochemistry efficiency at both the PSII and PSI levels. Nitric oxide supplementation through SNP ameliorated Cd stress by enhancing all the above mentioned parameters but causing a reduction in the Fo, and non-photochemical parameters of PSII and PSI in pea plants. These data indicate that the exogenous application of NO was useful in mitigating Cd-induced damage to photosynthesis in pea seedling.     

外源NO对水分胁迫下平邑甜茶幼苗氧化损伤的缓解效应

以苹果属植物平邑甜茶水培幼苗为试验材料,采用20%PEG-6000模拟水分胁迫,进行了外源NO对水分胁迫下平邑甜茶幼苗氧化损伤的缓解效应研究。结果表明:100~500μmol·L-1外源硝普钠(SNP,NO供体)处理,能在一定程度上提高渗透胁迫下平邑甜茶叶片内SOD、POD、CAT、APX活性和ASA含量,不同程度减轻20%PEG-6000胁迫对平邑甜茶幼苗活性氧的累积和氧化损伤,其中以300μmol·L-1 SNP处理缓解效应最佳,而相对高浓度的700μmol·L-1 SNP处理则不能起到缓解作用,反而有一定的毒害作用。     

甜瓜幼苗叶片内源一氧化氮和蔗糖代谢对低温胁迫的响应

以低温敏感型甜瓜品种‘XL-1’和耐低温型品种‘红优’为试材,采用6℃低温处理0、1、3、6、12、24h及3d、5d和7d,研究低温胁迫下甜瓜幼苗叶片中NO合成和蔗糖代谢的变化特征。结果表明:(1)低温胁迫能提高甜瓜幼苗叶片中硝酸还原酶(NR)活性,诱导促进NO生成,其中耐低温型甜瓜‘红优’中NO对低温的响应时间更早,变化幅度更大。(2)与对照相比,低温胁迫处理提高了2种甜瓜幼苗叶片中蔗糖、果糖和葡萄糖含量,增加了蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS)、酸性转化酶(AI)和中性转化酶(NI)活性,降低了淀粉含量。(3)低温胁迫处理使2种甜瓜叶片中渗透调节物质可溶性糖、可溶性蛋白、脯氨酸的含量上升。研究发现,低温胁迫通过增加甜瓜体内NO合成酶的活性刺激体内NO合成,通过促进蔗糖代谢相关酶的活性,提高蔗糖、果糖和葡萄糖的含量,从而响应低温胁迫,且低温胁迫诱导的糖分物质积累时间晚于NO的产生时间。     

Effects of Nitrate and L-Arginine on Content of Nitric Oxide and Activities of Antioxidant Enzymes in Roots of Wheat Seedlings and Their Heat Resistance

Separate and combined effects of nitrate (NaNO₃) and L-arginine as potential sources of nitric oxide (NO) on the content of endogenous NO in roots of wheat (Triticum aestivum L.) seedlings and on their heat resistance were studied. Both agents increased the seedling resistance to the damaging heating; the effect was maximal at 20 mM NaNO₃ or 5 mM L-arginine. The treatment with L-arginine elevated the NO content in the roots within the first 2 h of the treatment. Nitrate caused a stronger and longer rise in nitric oxide. Activity of nitrate reductase considerably (2–3 times) increased in the roots exposed to nitrate. The augmentation in the nitric oxide level caused by nitrate or L-arginine was prevented by the root pretreatment with an inhibitor of nitrate reductase (sodium tungstate) or an inhibitor of animal NO-synthase—N^G-nitro-L-arginine methyl ester (L-NAME). Upon the combined treatment with NaNO₃ and L-arginine, the nitrateinduced stimulation of the nitrate reductase activity, NO level in the roots, and seedling heat resistance were less pronounced than after separate application. In the presence of L-NAME, the negative influence of L-arginine on nitrate effects was markedly attenuated. The plant exposure to nitrate or L-arginine increased the activities of antioxidant enzymes (superoxide dismutase, catalase, and guaiacol peroxidase). A mixture of NaNO₃, and L-arginine caused weaker effects. It was suggested that nitrate-dependent and arginine-dependent pathways of NO formation are antagonistic to each other in wheat roots.     

外源一氧化氮对镉胁迫下绿豆幼苗根尖抗氧化酶的影响

采用水培法研究外源一氧化氮对镉(Cd)胁迫下绿豆幼苗根尖抗氧化酶活性的影响。结果表明:0.01mmol/L和0.1mmol/L一氧化氮供体硝普钠(sodium nitroprusside,SNP)显著促进上胚轴生长,1mmol/LSNP则抑制绿豆幼苗生长。Cd单独处理抑制根尖抗坏血酸过氧化物酶(ascorbate peroxidase,APX)和超氧化物歧化酶(superoxide dismutase,SOD)活性而刺激脂氧合酶(lipoxygenase,LOX)、谷胱甘肽转硫酶(glutathione S-transferase,GST)、谷胱甘肽还原酶(glutathione reductase,GR)和过氧化物酶(guaiacol peroxidase,POD)活性上升。0.1mmol/LSNP预处理能够明显缓解Cd对根生长的抑制,降低根尖中MDA含量,提高根尖APX和SOD活性,降低LOX和POD活性,但不影响GST和GR活性。     

外源NO对盐胁迫下黑麦草幼苗根生长抑制和氧化损伤的缓解效应

研究了外源一氧化氮(nitric oxide, NO)对盐胁迫下黑麦草幼苗根生长和氧化损伤的影响。结果表明,5~100 μmol·L^-1的NO供体硝普钠(sodium nitroprusside, SNP)处理显著减轻100mmol·L^-1 NaCl胁迫对黑麦草幼苗根生长的抑制效应,其中50 μmol·L^-1的SNP效果最明显,150 μmol·L^-1以上的SNP处理则抑制根的生长。50 μmol·L^-1 SNP处理提高了100 mmol·L^-1 NaCl胁迫下黑麦草幼苗根组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)及液泡膜上H⁺-ATP酶(H⁺-ATPase)和H⁺焦磷酸酶(H⁺-PPase)的活性,使谷胱甘肽(GSH)、抗坏血酸(ASA)和脯氨酸含量及K⁺/Na⁺、(Spd+Spm)/Put比值和根干物质积累量增加,超氧阴离子(O^-₂)、H₂O₂和丙二醛(MDA)含量降低,而1mmol·L^-1NO清除剂PTIO和1 μmol·L^-1 NaNO₂处理(对照)的效果则不明显。由此推断,NO通过提高根组织的抗氧化和渗透调节能力,促进根系对K⁺的选择性吸收及Put向Spd和Spm的转化,降低Na⁺的吸收并加强在液泡中的区隔化缓解盐胁迫对黑麦草幼苗根生长的抑制和膜脂过氧化损伤。