硫代腺苷甲硫氨酸促进番茄百菌清降解的生理机制

【目的】 探讨硫代腺苷甲硫氨酸（SAM）对番茄农药代谢调控的生理机制,为蔬菜安全生产奠定理论基础。【方法】 本研究选取鲜食樱桃番茄‘千禧’为供试植物,以生产上广泛应用的广谱性杀菌剂‘百菌清’为供试农药,研究外源SAM对番茄果实喷施百菌清后的农药残留量、活性氧含量和谷胱甘肽代谢系统的影响。【结果】外源喷施0.5—2 μmol·L ^-1的SAM均能显著降低番茄果实的百菌清残留量;但当外源SAM处理浓度达到0.5 μmol·L ^-1后,番茄果实中的百菌清残留量并未随着处理浓度的增加而下降。与对照相比,喷施百菌清后番茄果实的谷胱甘肽S-转移酶（GST）、谷胱甘肽还原酶（GR）和脱氢抗坏血酸还原酶（DHAR）活性显著上升;还原型谷胱甘肽（GSH）、氧化型谷胱甘肽（GSSG）和总谷胱甘肽含量（GSH+GSSG）变化也呈现上升趋势,谷胱甘肽的还原氧化比（GSH/GSSG）呈先上升后下降趋势;超氧阴离子（$\mathop{{O}}_{2}^{{\mathop{}_{\ ·}^{-}}}$）和过氧化氢（H₂O₂）含量显著上升,而丙二醛（MDA）含量与对照相比差异不显著。外源喷施0.5 μmol·L ^-1的SAM可显著提高百菌清处理下GST、GR和DHAR的活性,增加GSH和GSH+GSSG含量,降低处理10 d后的植株GSSG含量,提高GSH/GSSG;提高处理2—5 d的植株$\mathop{{O}}_{2}^{{\mathop{}_{\ ·}^{-}}}$和H₂O₂含量,但对MDA含量无显著影响。【结论】外源添加0.5 μmol·L ^-1的SAM可激活谷胱甘肽循环系统关键酶GR和DHAR活性,促进GSH再生,依赖GST并协同$\mathop{{O}}_{2}^{{\mathop{}_{\ ·}^{-}}}$和H₂O₂的氧化作用,促进番茄果实中的百菌清降解。     

Effects of Different Cadmium Levels on Active Oxygen Metabolism and H2O2-Scavenging System in Brassica campestris L.ssp.chinensis

The effects of different Cd (Cadmium) levels on generation of active oxygen speceies(AOS) and H2O2-scavenging system in the leaves of Brassica campestris L. ssp. chinensiswere studied. The results showed that O2 generation rate, and H2O2 content were enhancedand malondialdehyde (MDA) content increased with the increase of Cd concentrations inthe growth medium. The activities of ascorbate peroxidase (APX), dehydroascorbatereductase (DR) and glutathione reductase (GR) were promoted by the addition of Cd.Exposed to Cd also increased the contents of ascorbate (ASA) and glutathione (GSH) in theleaves.     

外源AsA对苹果果实采后衰老及AsA-GSH循环的影响

 以苹果(Malus domestica Borkh．)品种“嘎拉”果实为试材,研究了外源抗坏血酸(AsA)处理对采后果实成熟衰老及其过程中抗坏血酸-谷胱甘肽(AsA GSH)循环各组分的影响。结果表明,在嘎拉苹果果实常温贮藏过程中,贮藏前期AsA再生酶单脱氢抗坏血酸还原酶(MDHAR) 和脱氢抗坏血酸还原酶(DHAR)活性升高,AsA含量上升。但在贮藏后期,AsA,脱氢抗坏血酸(DHA)、谷胱甘肽(GSH)、氧化态谷胱甘肽（GSSG）、总抗坏血酸和总谷胱甘肽含量都开始迅速下降。10mmol/L外源AsA处理降低了果实相对膜透性、MDA和H2O2含量,提高了贮藏前期AsA-GSH循环系统相关酶（抗坏血酸还原酶(APX),MDHAR,DHAR和谷胱甘肽还原酶(GR)）的活性,AsA和GSH水平,增加了AsA/DHA比率。     

土壤紧实胁迫对黄瓜抗坏血酸-谷胱甘肽循环的影响

【目的】探索土壤紧实胁迫对黄瓜产生伤害的机理,为土壤的可持续利用提供参考。【方法】用容重为1.20 g•cm-3的疏松土壤和1.55 g•cm-3的紧实土壤进行盆栽试验,研究土壤紧实胁迫对‘津春4号’黄瓜叶片及根系中抗坏血酸-谷胱甘肽循环（AsA-GSH）的影响。【结果】在土壤紧实胁迫条件下,黄瓜叶片及根系中过氧化氢（H2O2）含量和丙二醛（MDA）含量显著提高,且根系中两种物质的增幅高于叶片,表明根系的伤害程度高于叶片。与此同时,叶片及根系中还原型抗坏血酸（AsA）含量、AsA+DHA量、ASA/DHA显著降低,脱氢抗坏血酸（DHA）含量显著提高;还原型谷胱甘肽（GSH）含量显著下降,氧化型谷胱甘肽（GSSG）含量、GSSG/GSH比值显著提高,GSSG+GSH变化甚微,表明AsA及GSH被消耗以清除H2O2。叶片及根系中抗坏血酸过氧化物酶（APX）、单脱氢抗坏血酸还原酶（MDHAR）、脱氢抗坏血酸还原酶（DHAR）和谷胱甘肽还原酶（GR）活性显著升高,且APX的活性水平远远高于MDHAR、DHAR及GR,表明APX在清除H2O2的过程中氧化AsA的能力远远高于MDHAR和DHAR再生AsA的能力及GR将GSSG还原成GSH的能力。【结论】在土壤紧实胁迫条件下,黄瓜秧苗（叶片及根系）中的AsA-GSH循环加强,削弱了土壤紧实胁迫造成的伤害。     

Photosynthesis,Growth and Antioxidant Metabolism in Mustard （Brassica juncea L.） Cultivars Differing in Cadmium Tolerance

Two mustard （Brassica juncea L. Czern and Coss.） cultivars, Pusa Jai Kisan and SS2 differing in cadmium （Cd） tolerance were treated with 0, 25 and 50 umol L-1 Cd to study the physiological basis of difference in Cd tolerance. Cultivar SS2 （Cd sensitive） accumulated greater Cd in leaves than Pusa Jai Kisan （Cd tolerant）. Further, SS2 also exhibited higher contents of thiobarbituric acid reactive substances （TBARS） and H2O2 and electrolyte leakage. However, the activities of antioxidant enzymes, catalase （CAT）, ascorbate peroxidase （APX）, dehydroascorbate reduetase （DHAR）, and glutathione reductase （GR） were higher in Pusa Jai Kisan than those in SS2. Contrarily, the activity of superoxide dismutase （SOD） was higher in SS2 than that in Pusa Jai Kisan and was the greatest at 25 umol L-1 Cd. Treatment of 25 umol L-1 Cd induced the maximum activity of enzymes. However, the activity of GR increased up to 50 umol L-1 Cd in both the cultivars. The non-enzymatic antioxidants ascorbate （AsA） and glutathione （GSH） were higher in Pusa Jai Kisan than that in SS2, whereas dehydroascorbate （DHA） and oxidized glutathione （GSSG） were higher in SS2. Photosynthesis and growth were adversely and maximally decreased by 50 umol L-1 Cd treatment in both the cultivars, but SS2 exhibited greater reductions. The protection of photosynthesis and growth and lesser reduction in Pusa Jai Kisan were associated with its capacity to restrict accumulation of Cd in leaves resulting in lower level of TBARS and H2O2 and electrolyte leakage. Moreover, Pusa Jai Kisan exhibited efficient antioxidant metabolism for removal of Cd-induced reactive oxygen species.     

镉胁迫对两种海洋微藻生长和抗氧化系统的影响

采用实验生态学和生物化学的方法,研究了不同含量Cd（Ⅱ）（0.05、0.1、0.5、1.0 mmol/L）对两种海洋微藻的可溶性蛋白含量、超氧化物歧化酶（SOD）活性、过氧化氢（H2O2）、丙二醛（MDA）和还原型谷胱甘肽（GSH）含量的影响。结果表明：0.05 mmol/L的Cd（Ⅱ）对湛江等鞭金藻Isochrysis zhan-jiangensis的生长无明显影响,与对照组相比,可溶性蛋白含量略微增加,而高浓度（〉0.05 mmol/L）的Cd（Ⅱ）对湛江等鞭金藻的生长有显著抑制作用,可溶性蛋白含量也迅速减少;普通小球藻Chlorella vul-garis的生长也明显受到Cd（Ⅱ）的抑制,可溶性蛋白含量减少。Cd（Ⅱ）胁迫抑制了两种藻类的SOD活性;随着Cd（Ⅱ）浓度增加,普通小球藻和湛江等鞭金藻的H2O2和MDA含量升高,普通小球藻的GSH含量升高,而湛江等鞭金藻的GSH含量在低浓度Cd（Ⅱ）胁迫下有所升高,高浓度时则下降。Cd（Ⅱ）胁迫对普通小球藻和湛江等鞭金藻的生长和抗氧化系统都产生了一定程度的影响。     

镉对背角无齿蚌主要组织谷胱甘肽含量和相关酶活性的影响

为了进一步探明谷胱甘肽系统对镉引起的氧化损伤的防御作用,根据背角无齿蚌(Anodonta woodiana woodiana)96 h镉的半致死浓度,设置5个染毒组(4.22、8.43、16.86、33.72、67.45 mg·L-1)和1个对照组,处理24、48、72、96 h分别测定鳃与肝脏中还原型谷胱甘肽(GSH)、氧化型谷胱甘肽(GSSG)含量和谷胱甘肽硫转移酶(GST)、谷胱甘肽还原酶(GR)的活性。实验结果显示,与对照组相比,除48 h、4.22 mg·L-1处理组鳃中GSSG含量出现显著性升高(P0.05)外,GSH和GSSG含量均表现为显著或极显著性降低(P0.05,P0.01);随着时间的延长,GSH/GSSG比值在低浓度(4.22、8.43 mg·L-1)处理组先降后升,在高浓度(33.72、67.45 mg·L-1)处理组则逐渐下降,且与对照组相比差异显著(P0.05)。与对照组相比,在24 h鳃中GST活性呈梯度型降低(P0.01);在48、72、96 h GST活性整体呈升高趋势,且在低浓度组升高、高浓度组降低,呈现显著性或极显著性差异(P0.05,P0.01)。鳃中GR活性在48 h、8.43 mg·L-1,72 h、67.45 mg·L-1和96 h、4.22 mg·L-1处理组出现显著性升高。随着浓度的升高和时间的延长,肝脏中GSH含量和GSH/GSSG比值呈显著或极显著性降低(P0.05,P0.01)。肝脏中GST活性整体呈升高趋势且有极显著性差异(P0.01);在24 h、4.22 mg·L-1处理组GST活性达到最高。同一时间,随着镉浓度的升高,肝脏中GST活性逐渐降低。肝脏中GR活性整体呈升高趋势且有显著性或极显著性差异(P0.05,P0.01),在72 h、4.22 mg·L-1处理组浓度达到最高。研究表明,肝脏中GSH含量的变化对镉引起的损伤反应灵敏且发挥了重要作用,GST解毒酶对镉的毒性反应灵敏,且肝脏较鳃的反应迅速。GSH含量、GST活性和肝脏分别可以作为环境监测的生化指标和靶器官。     

Coordinate induction of antioxidant defense and glyoxalase system by exogenous proline and glycinebetaine is correlated with salt tolerance in mung bean

The purpose of this study was to assess the synergistic effects of exogenously applied proline and glycinebetaine (betaine) in antioxidant defense and methylglyoxal (MG) detoxification system in mung bean seedlings subjected to salt stress (200 mmol·L⁻¹ NaCl, 48 h). Seven-day-old mung bean seedlings were exposed to salt stress after pre-treatment with proline or betaine. Salt stress caused a sharp increase in reduced glutathione (GSH) and oxidized glutathione (GSSG) content in leaves, while the GSH/GSSG ratio and ascorbate (AsA) content decreased significantly. The glutathione reductase (GR), glutathione peroxidase (GPX), glutathione S-transferase (GST) and glyoxalase II (Gly II) activities were increased in response to salt stress, while the monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), catalase (CAT) and glyoxalase I (Gly I) activities sharply decreased with an associated increase in hydrogen peroxide (H₂O₂) and lipid peroxidation level (MDA). Proline or betaine pre-treatment had little influence on nonenzymatic and enzymatic components as compared to those of the untreated control. However, proline or betaine pre-treated salt-stressed seedlings showed an increase in AsA, GSH content, GSH/GSSG ratio and maintained higher activities of APX, DHAR, GR, GST, GPX, CAT, Gly I and Gly II involved in ROS and MG detoxification system as compared to those of the untreated control and mostly also salt-stressed plants with a simultaneous decrease in GSSG content, H₂O₂ and MDA level. These results together with our previous results suggest that coordinate induction of antioxidant defense and glyoxalase system by proline and betaine rendered the plants tolerant to salinity-induced oxidative stress in a synergistic fashion.     

Effects of Exogenous Silicon on the Activities of Antioxidant Enzymes and Lipid Peroxidation in Chilling-Stressed Cucumber Leaves

In order to increase vegetable productivity by improving environmental conditions, this article investigates the effects of exogenous silicon on the activities of major antioxidant enzymes and on lipid peroxidation under chilling stress, and it examines whether silicon-induced chilling tolerance is mediated by an increase in antioxidant activity. Cucumis sativus cv. Jinchun 4 was hydroponically cultivated to the two-leaf stage, at which point seedlings were watered with different concentrations of silicon （0, 0.1 and 1 mmol L^-1） and separately exposed to normal （25/18℃） or chilling （15/8℃） temperatures for six days under low light （100μmol m^-2 s^-9. Data were collected from the second leaves on the percentage of withering and the levels of endogenous silicon, malondialdehyde （MDA）, hydrogen peroxide （H202）, superoxide radical （O2^.-）, superoxide dismutase （SOD, EC 1.15.1.1）, glutathione peroxidase （GSH-Px, EC 1.11.1.9）, ascorbate peroxidase （APX, EC 1.11.1.11）, monodehydroascorbate reductase （MDHAR, EC 1.6.5.4）, glutathione reductase （GR, EC 1.6.4.2）, reduced glutathione （GSH） and ascorbate （AsA）. Compared to normal temperatures, chilling resulted in partially withered leaves and increased MDA content. When 0.1 or 1 mmol L^-1 exogenous silicon was combined with chilling, the withering of the cucumber leaves was reduced relative to the original chilling treatment, while the endogenous silicon content was increased, antioxidants such as SOD, GSH-Px, APX, MDHAR, GR, GSH, and AsA were more active, and the levels of H2O2, O2^.-, and MDA were lower. We propose that exogenous silicon leads to greater deposition of endogenous silicon and thereby increases antioxidant activities and reduces lipid peroxidation induced by chilling.     

钙和热加钙处理对桃冷藏期间H_2O_2清除系统的作用

本文分析了钙处理及热加钙处理对桃冷藏期间Ｈ＿２Ｏ＿２含量以及其清除系统中的重要物质ＧＳＨ（谷胱甘肽）、抗坏血酸含量和ＧＲ（谷胱甘肽还原酶）活性的影响，结果表明：钙处理降低了桃中Ｈ＿２Ｏ＿２的积累，对抗坏血酸含量变化无影响，延迟了ＧＳＨ含量的积累，增加了ＧＲ活性，热加钙处理降低了桃中Ｈ＿２Ｏ＿２的含量，提高了抗坏血酸的含量，推迟了ＧＳＨ含量高峰出现的时间，降低了ＧＲ活性     

Effect of Foliar GA3 and ABA Applications on Reactive Oxygen Metabolism in Black Currants (Ribes nigrum L.) During Bud Para-dormancy and Secondary Bud Burst

The secondary bud burst can cause around 10％-20％ yield losses in black currants, an economically important crop in parts of Europe, Asia and North America. The metabolism of reactive oxygen species (ROS) has been linked to bud dormancy and its early release (secondary bud burst) in several fruit crops. But the relationship between ROS metabolism and the secondary bud burst is still not well understood in black currants. In the present study, two black currant cultivars (Adelinia and Heifeng) with opposing tendency of exhibiting the secondary bud burst were sprayed with abscisic acid (ABA) and gibberellic acid (GA3) to either inhibit or induce the secondary bud burst. The results showed that ABA inhibited the secondary bud burst by reducing the contents of ROS (H2O2, O2-?) in buds; decreasing the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT); and increasing the contents of oxidized glutathione (GSSG) and ascorbic acid (AsA). GA3 effectively induced the secondary bud burst by increasing ROS contents; increasing the activities of several antioxidant enzymes, such as SOD, POD, CAT, glutathione reductase (GR), ascorbate peroxidase (APX) and the contents of reduced glutathione (GSH); and decreasing the contents of AsA. The experimental results showed that GA3 treatment increased the content of ROS, accelerated the metabolism of reactive oxygen species, and promoted the second burst of black currants. However, ROS metabolism was at a low level under ABA treatment, and the buds remained dormant. These results suggested that ROS metabolism might play an important role in the two black currants of the secondary bud burst.     

烟草叶片发育过程中抗坏血酸-谷胱甘肽循环清除H2 O2 的研究

[目的]研究烟草叶片发育过程中H2O2积累以及抗坏血酸-谷胱甘肽(AsA-GSH)循环清除H2O2能力的变化。[方法]以烟草(Nicotiana tabacumL.cvNC89&JYH)为材料,研究了叶片发育过程中H2O2积累与AsA-GSH循环的关联。[结果]结果表明,抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)活性,AsA、GSH含量在叶片幼嫩及成熟时期维持较高水平,衰老时下降较快,与H2O2含量存在相关性,且AsA-GSH循环系统在运行过程中保持平衡。[结论]AsA-GSH循环系统的运行与H2O2代谢存在相关性。     

Effects of Water Stress on Reactive Oxygen Species Generation and Protection System in Rice During Grain-Filling Stage

Rice is one of the main staple food crops in the world, but it may suffer serious water stress during growth period. Water stress during grain filling results in decreased grain yeild, but its mechanism generating and scavenging the active oxygen is unclear under continuance of the water stress. The experiment was carried out in growth chamber to investigate the effects of water stress on the production of superoxide free radical （O2）, hydrogen peroxide （H202）, malondialdehyde （MDA）, reduced glutathione （GSH）, ascorbic acid （AsA）, and antioxidative enzyme activities in three rice hybrids with differing drought resistant under both normal and drought conditions during grain-filling stage. The results showed that water stress aggravated the membrane lipid peroxidation in rice leaves, which was more severe in less drought resistant hybrids than that in more tolerant ones. Also O2＇ and H2O2 accumulated more rapidly in less drought resistant hybrids than that in more tolerant ones. During water stress, decreases of GSH, AsA, chlorophyll, and relative water contents in more drought resistant hybrids were obvious less than those in less tolerant ones. Activities of superoxide dismutase （SOD）, catalase （CAT） and peroxidase （POD） in/eaves increased obviously in 0-14 d after heading and subsequently decreased rapidly, and those in more drought resistant hybrids were more than those in less tolerant ones. The results showed that changes of O2, H2O2, MDA, GSH, and AsA contents and antioxidative enzyme activities correlated significantly to drought resistance of rice hybrids, and more drought resistant hybrids possessed high ant oxidation capacity.     

二溴海因对吉富罗非鱼血浆的氧化胁迫效应

采用半静态水质接触染毒法,研究不同浓度(0、0.06、0.3、1.5 mg·L^-1)、不同时间(1、2、4、8、16、26 d)下二溴海因对吉富罗非鱼血浆总还原性谷胱甘肽(T-GSH)、氧化型谷胱甘肽(GSSG)、谷胱甘肽-S-转移酶(GST)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽还原酶(GR)、谷胱甘肽过氧化物酶(GPx)及总抗氧化能力(T-AOC)的影响。结果表明:随着暴露时间的延长,血浆SOD、GR先降低后趋于稳定,T-GSH、GSH/GSSG、CAT、GST呈先升高后下降的趋势,且16 d出现显著性升高,GPx在1 d和16 d时被诱导,T-AOC仅在16 d时被诱导。CAT、GPx、T-GSH、GSH/GSSG、T-AOC等指标表现出浓度依赖现象,T-AOC与二溴海因呈剂量效应关系。除CAT、GR外,解除胁迫10 d后各抗氧化指标均未恢复到正常水平。上述结果显示,二溴海因对吉富罗非鱼血浆的抗氧化系统有显著的影响, T-AOC宜作为生物标志物,高浓度的二溴海因暴露能造成血液中抗氧化系统的不可逆损伤。     

谷胱甘肽对奥尼罗非鱼原代肝细胞增殖及生化功能的影响

【目的】研究谷胱甘肽(Glutathione,GSH)对奥尼罗非鱼Oreochromis niloticus×O.aureus原代肝细胞增殖和生化功能的影响,探究谷胱甘肽的促生长作用机制。【方法】用添加φ为10%胎牛血清和未添加血清的培养液培养奥尼罗非鱼原代肝细胞48 h,随后在培养液中分别加GSH至0、30、100、300、900 mg·L~(-1),每个水平设6个重复,培养24、48和72 h后测定奥尼罗非鱼原代肝细胞增殖情况及培养液中胰岛素样生长因子、白蛋白、过氧化氢含量和谷草转氨酶、γ-谷氨酰转肽酶活性。【结果】谷胱甘肽显著促进了奥尼罗非鱼原代肝细胞增殖,提高了培养液上清中胰岛素样生长因子、白蛋白的含量和γ-谷氨酰转肽酶活性,降低了培养液上清中过氧化氢含量和谷草转氨酶活性(P0.05)。在无血清培养试验组中添加谷胱甘肽,对奥尼罗非鱼原代肝细胞增殖及生化指标的影响比添加血清培养试验组效果明显。【结论】谷胱甘肽能促进奥尼罗非鱼肝细胞增殖,且具有保护肝脏的作用。     

外源一氧化氮对冷害胁迫下棉花幼苗生长、抗氧化系统和光合特性的影响

【目的】探讨外源NO供体硝普钠（SNP）提高新疆棉花抗逆能力的内在机制。【方法】以棉花新陆早13号、新陆早33号为材料,通过室内人工模拟低温逆境的方法,研究SNP（100 μmol•L-1）对冷害胁迫下棉花幼苗的生长、叶绿素含量、气体交换参数、叶绿素荧光参数及活性氧代谢的影响。【结果】在正常生长条件下SNP对棉花幼苗生长、过氧化氢（H2O2）、脯氨酸（Pro）、可溶性蛋白质和超氧化物歧化酶（SOD）影响不大,但显著提高了过氧化物酶（POD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）和谷胱甘肽还原酶（GR）活性;此外,叶绿素含量、净光合速率（Pn）、胞间二氧化碳浓度（Ci）、最小荧光产量（F0）和最大光化学效率（Fv/Fm）无明显影响,而气孔导度（Gs）、蒸腾速率（Tr）、光合电子传递速率（ETR）和光系统Ⅱ实际量子效率（ΦPSⅡ）显著增加;冷害胁迫下,外源NO处理显著提高了叶片的生长速率、SOD、POD、CAT、APX和GR的活性以及Pro和可溶性蛋白质含量,减少了H2O2和膜脂过氧化产物MDA的积累;外源NO明显提高了棉花叶片叶绿素含量、Pn、Gs、Tr、Fv/Fm、ETR和ΦPSⅡ,降低Ci和增加非光化学猝灭系数（NPQ）,避免过量的光伤害,维持较高的光系统Ⅱ活性。【结论】低温胁迫下,外源NO通过促进抗氧化酶活性和抗氧化剂含量的提高,降低H2O2和MDA的积累,保护了细胞膜结构的稳定性,从而减轻了冷害胁迫对棉花光系统Ⅱ的伤害,增强棉花的抗冷性。     

不同耐冷性杂草稻和栽培稻抗氧化系统对冷水胁迫的响应

【目的】从孕穗期到抽穗开花是水稻对温度最为敏感的阶段,这一阶段的低温冷害严重制约了东北地区水稻生长和种植面积的进一步扩大,探明水稻耐冷生理机制,将为东北水稻生产提供重要保障。探索耐冷性不同的杂草稻和栽培稻在冷水胁迫下开花期剑叶的活性氧代谢、抗氧化酶活性和抗氧化剂含量的变化规律,为耐冷性水稻品种的选育和栽培提供理论依据。【方法】以耐冷性强的杂草稻WR03-45、栽培稻丽江新团黑谷和冷敏感的杂草稻WR03-26、栽培稻秀子糯为试验材料,采用盆栽方法,根据剑叶叶枕距判断主穗进入孕穗期的时间,于孕穗期在冷水池中进行低温处理,未经冷水处理的参试材料作为对照。在开花期,剪取参试材料的剑叶保存于-85℃的超低温冰箱中,用于测定超氧阴离子自由基（）产生速率、过氧化氢（H₂O₂）含量、丙二醛（MDA）含量以及超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）和谷胱甘肽还原酶（GR） 5种抗氧化酶活性和还原型抗坏血酸（AsA）、还原型谷胱甘肽（GSH）两种抗氧化剂含量,研究孕穗期低温冷害对剑叶的活性氧（ROS）积累、抗氧化酶活性和抗氧化剂含量的影响。【结果】冷水胁迫下,冷敏感的杂草稻WR03-26开花期剑叶仅有CAT和GR活性显著增加,冷敏感的栽培稻秀子糯开花期剑叶SOD、CAT和GR活性显著增加;WR03-26和秀子糯剑叶的AsA和GSH含量及AsA/DHA值和GSH/GSSG值与对照无显著差异;WR03-26和秀子糯剑叶产生速率显著增加,H₂O₂含量极显著增加,膜脂过氧化产物MDA含量显著增加。耐冷性强的杂草稻WR03-45开花期剑叶SOD活性显著升高,POD、APX、CAT和GR极显著升高,耐冷性强的栽培稻丽江新团黑谷开花期剑叶SOD、POD和APX活性显著升高,CAT和GR活性极显著升高;WR03-45和丽江新团黑谷剑叶的抗氧化剂（AsA和GSH）含量及AsA/DHA值和GSH/GSSG值在冷水胁迫下显著高于对照;WR03-45和丽江新团黑谷剑叶产生速率、H₂O₂含量和MDA含量与对照相比无显著差异。【结论】冷水胁迫下,耐冷性强的水稻通过提高抗氧化酶活性和抗氧化剂含量,减少ROS的积累以及膜脂过氧化,增强对冷水胁迫的耐性。水稻的耐冷性与胁迫下抗氧化系统清除ROS的能力有关,杂草稻WR03-45作为一种强耐冷性的种质资源可以用于栽培稻耐冷性的遗传改良。     

遮荫处理对早熟花椰菜花球的生长和抗氧化系统的影响

以早熟花椰菜品种丰喜45天'为材料,在花球开始形成期进行遮荫处理,以研究遮荫对花球生长和抗氧化系统的影响.结果表明:(1)遮荫处理使花椰菜花球纵径、横径和鲜重分别比对照减少17.97%、18.9%和38.59%.(2)除了叶片中愈创木酚过氧化物酶(G-POD)活性显著提高外,遮荫处理降低了花椰菜叶片、花蕾和花茎中超氧化物歧化酶(SOD)、过氧化物酶(CAT)、抗坏血酸过氧化物酶(APX)和G-POD的活性,但与叶片相比,花蕾和花茎中这些酶活性的下降幅度较小.(3)遮荫处理显著降低了花椰菜叶片、花蕾、花茎中脱氢抗坏血酸还原酶(DHAR)和谷胱甘肽还原酶(GR)的活性.(4)遮荫处理降低了花椰菜叶片、花蕾和花茎中抗坏血酸含量(花蕾中还原型抗坏血酸除外)和叶片中谷胱甘肽含量,但花蕾和花茎中谷胱甘肽反而有所提高(花茎中还原型谷胱甘肽除外).     

镉对白菜活性氧代谢及H2O2清除系统的影响

研究不同浓度镉对白菜(Brassica campestris L.ssp.chinensis)叶片活性氧产生及H2O2清除酶活性影响。结果表明,培养液中加镉增加了白菜叶片中超氧自由基(O2-)的产生速率和H2O2含量,过氧化产物丙二醛(MDA)含量随培养液中镉浓度和镉处理时间增加而增加。在加镉条件下,抗坏血酸过氧化物酶(APX)活性、脱氢抗坏血酸还原酶(DR)和谷胱甘肽还原酶(GR)活性升高,抗坏血酸(AsA)和谷胱甘肽(GSH)含量增加。     

短枝木麻黄幼苗对低温胁迫的生理响应

以短枝木麻黄Casuarina equisetifolia耐寒无性系ZS7和不耐寒无性系HN1幼苗为供试材料,在人工气候箱内采用基质栽培方式,研究在-2,-5,-8,-11 ℃共4个温度梯度胁迫2 h以及-5 ℃持续胁迫1,2,5,8,16,24,48,72 h后2种无性系幼苗相关生理指标的变化趋势以及耐寒性差异,探讨短枝木麻黄适应低温环境的生理机制。结果表明:在低温梯度胁迫下,耐寒无性系的过氧化氢（H₂O₂）和丙二醛（MDA）质量摩尔浓度的增幅小于不耐寒无性系;叶绿素、脯氨酸（Pro）和可溶性蛋白质质量分数,超氧化物歧化酶（SOD）,过氧化物酶（POD）,过氧化氢酶（CAT）,抗坏血酸过氧化物酶（APX）和谷胱甘肽还原酶（GR）活性,以及还原型谷胱甘肽（GSH）和氧化型谷胱甘肽（GSSG）质量摩尔浓度的降幅均小于不耐寒无性系。耐寒无性系的GSH/GSSG比值呈上升的趋势,而不耐寒无性系的呈先下降后上升趋势。在-5 ℃持续胁迫下,2种无性系各生理指标呈现波动变化,增幅（降幅）与到达峰值时间不同。无论是在低温梯度胁迫还是在低温持续胁迫处理过程中,耐寒无性系的SOD,POD,CAT,APX和GR活性以及叶绿素、可溶性蛋白质和Pro质量分数、GSH质量摩尔浓度都显著高于不耐寒无性系。耐寒性不同的2种短枝木麻黄无性系耐寒的生理机制明显不同,耐寒性强的无性系通过在低温胁迫下保持较高的可溶性蛋白质和Pro等渗透调节物质质量分数,增强抗氧化酶活性,提高非酶抗氧化剂水平,抑制叶绿素质量分数的下降及膜脂过氧化程度的加剧,进而提高抗寒性来抵御低温。