烯效唑对不同耐旱性甘薯品种苗期根系抗氧化酶同工酶的影响

本试验以耐旱性较强的JS21和耐旱性较差的JZS1为材料,采用水培和PEG-6000模拟田间梯度干旱胁迫的方法,研究了烯效唑对不同耐旱性甘薯品种苗期根系可溶性蛋白和抗氧化酶同工酶的影响。结果表明：在正常供水条件下,烯效唑处理对两品种可溶性蛋白含量无明显影响,干旱条件下增加JZS1的可溶性蛋白含量,stripe2~stripe4明显变粗;降低JS21的可溶性蛋白含量,stripe3、stripe 4明显变细、变淡。正常供水条件下,烯效唑处理增加JS21的SOD2和SOD3、JZS1的CAT2和CAT3同工酶表达量,对JZS1的SOD同工酶表达量、两品种的POD同工酶表达量和JS21的CAT同工酶表达量均无明显影响。与正常供水条件相比,干旱处理增加JZS1的SOD1、SOD2、POD2和JS21的POD2、POD3的同工酶条带的表达量,降低JS21的SOD2同工酶表达量。干旱条件下,烯效唑处理增加JZS1中SOD1、SOD2、POD1、POD3、CAT2、CAT3同工酶条带的表达量。总之,与耐旱性较强的品种相比,干旱条件下烯效唑处理更能明显增强耐旱性较差的甘薯品种的抗氧化酶同工酶表达量。

不同毒物对猪肝线粒体抗氧化酶同工酶的影响

采用不同毒物联苯胺、六氯苯、甲基苯丙胺对猪肝线粒体进行体外染毒 ,所获得的抗氧化酶 (谷胱甘肽过氧化物酶GSH -Pox和超氧化物歧化酶SOD)同工酶在不同时间段处理过程中呈现出激活→减弱→抑制的变化趋势。结果表明 ,毒性作用可能为一种自由基机制 ,随着毒物作用时间的进一步延长 ,线粒体内活性氧自由基迅速增加 ,破坏了GSH -Pox和SOD的抗氧化活性 ,而导致其活力下降或丧失。

盐胁迫对黄瓜幼苗叶片、韧皮部渗出液和根系抗氧化酶同工酶表达的影响

黄瓜Cucumis sativus在设施生产中经常受到盐害,严重影响了黄瓜的产量和品质。以盐敏感黄瓜品种‘津优1号’Cucumis sativus‘Jinyou No.1’和相对较耐盐品种‘新泰密刺’Cucumis sativus‘Xintai Mici’为试材,采用水培,研究了氯化钠胁迫对幼苗叶片、根系和韧皮部渗出液超氧化物歧化酶(SOD),过氧化物酶(POD)和过氧化氢酶(CAT)同工酶表达影响。结果显示:叶片中共检测到9条超氧化物歧化酶,4条过氧化物酶和2条过氧化氢酶同工酶条带,盐胁迫抑制了‘新泰密刺’叶片超氧化物歧化酶、过氧化物酶和过氧化氢酶同工酶表达,而‘津优1号’叶片超氧化物歧化酶和过氧化氢酶同工酶表达增强。韧皮部渗出液有3条超氧化物歧化酶,2条过氧化物酶和1条过氧化氢酶同工酶条带;盐胁迫增强了‘新泰密刺’韧皮部渗出液中3种抗氧化酶同工酶表达,而抑制了‘津优1号’韧皮部渗出液中3种同工酶表达。在根系中共发现6条超氧化物歧化酶,7条过氧化物酶和1条过氧化氢酶同工酶条带,盐胁迫下2个品种根系过氧化氢酶同工酶的表达均增强,过氧化物酶同工酶在‘津优1号’中6条表达减弱,1条增强,在‘新泰密刺’中均增强,2个品种中3条相同超氧化物歧化酶同工酶在盐胁迫下表达减弱,2条在‘津优1号’中表达增强而‘新泰密刺’中无变化,1条在‘津优1号’中表达无变化而‘新泰密刺’中表达减弱。综上所述,3种抗氧化酶同工酶与其耐盐性均有密切关系,并暗示抗氧化酶同工酶响应盐胁迫的变化趋势具有品种及组织特异性。韧皮部渗出液中3种同工酶变化趋势在2个品种中完全相反,说明韧皮部是黄瓜幼苗响应盐胁迫的重要组织。

水稻根系抗氧化酶及其同工酶对酸雨胁迫的响应

为进一步认识植物对酸雨胁迫的适应性机制,本文选择具有较强耐酸性作物水稻为试材,研究酸雨(AR)(p H 3.5和p H 2.5)对水稻根系抗氧化酶活性及其同工酶组成的影响.发现AR胁迫5 d后,p H 3.5组水稻幼苗根系中SOD(超氧化物歧化酶)、CAT(过氧化氢酶)、POD(过氧化物酶)活性均上升,且同工酶谱条带均增粗变亮,H_2O_2、O_2^(·-)、MDA含量和质膜透性均增加,根长、根表面积、根体积、根冠比均减小;而p H 2.5组根系中虽SOD、CAT活性上升但POD活性下降,其中SOD、CAT同工酶谱条带变粗变亮且较p H 3.5组更粗更亮而POD 3、POD 4、POD 5条带明显变细变暗,O_2^(·-)、H_2O_2、MDA含量和质膜透性与根系生长各指标降幅均大于p H 3.5组.恢复5 d后,p H3.5组下水稻根系中SOD、CAT、POD、H_2O_2、O_2^(·-)、MDA含量和质膜透性恢复至对照水平,而p H 2.5引发的活性氧伤害未恢复.因此,AR胁迫下水稻幼苗根系SOD、CAT、POD同工酶表达量增加促使活性增强有助于清除AR诱发的活性氧积累,增强植物对酸雨的耐受性,调控能力受酸雨强度限制.

外源NO供体对水分亏缺下玉米叶片碳同化关键酶及抗氧化系统的影响

为了探讨外源NO供体(硝普钠,SNP)对水分亏缺下玉米叶片碳同化关键酶及抗氧化系统的影响及其调控机制,在20%PEG-6000模拟水分亏缺胁迫下,研究了SNP对玉米品种驻玉309幼苗叶片光合碳同化核酮糖-1,5-二磷酸羧化/加氧酶(Rubisco)和Rubisco活化酶(RCA)活性及其基因表达、抗氧化酶活性及其同工酶谱变化的影响。结果表明,在水分亏缺胁迫下,SNP显著上调玉米叶片rbc L、rbc S、rcaβ基因的相对表达量,尤其是叶片rbc S基因的相对表达量增加1.86倍,叶片Rubisco、RCA活性分别提高32.7%和14.67%;叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性及其同工酶谱带的宽度和亮度显著增强,而ROS积累量明显降低。说明在PEG水分亏缺胁迫下,SNP能显著提升玉米幼苗叶片光合碳同化能力及抗氧化酶活性,降低ROS积累及其对细胞膜造成的损伤,提高玉米的抗干旱性。

SODMC对水稻幼苗抗寒性影响的研究

以"早稻921"为实验材料,用一定浓度的SODMC(SuperoxideDismutaseModelCom-pound)(2.5mg/L)以浸种和喷洒相结合的方式处理水稻,研究SODMC对水稻幼苗抗寒性的影响,结果表明:SODMC处理能维持低温胁迫后水稻幼苗体内较高的SOD活性和Vc含量;SODMC处理能减轻低温胁迫造成的膜脂过氧化水平和电解质渗漏;SODMC处理能提高某些抗氧化同工酶的活性,使这些同工酶在低温胁迫后恢复时仍保持很高的活性,从而增强相应基因的表达,进而抵抗低温胁迫.

Analysis of Antioxidant Characteristics in Seedling Roots of Sweetpotato(Ipomoea batatas(L.) Lam.) with Different Drought Tolerance under Simulated Drought Stress

[Objective] Jishu 21 with strong drought tolerance and Jizishu 1 with weak drought tolerance were chosen to reveal antioxidant characteristics in seedling roots of sweetpotato with different drought tolerance. [Method] Active oxygen, antioxidant substances and antioxidant enzymes in seedling roots of sweetpotato with different drought tolerance were analyzed by hydroponics with PEG-6000 for simulating drought stress in the experiment. [Result] The results showed that under drought stress, H202 content and formation rate of 02_ in seedling roots of Jizishul were higher than Jishu 21 by 1.9% and 102.6%, respectively, the contents of Vc in seed- ing roots of Jizishu 1 and Jizishu 1 increased by 25.3% and 81.1%, respectively, and the contents of polyphenols increased by 24.8% and 37.6% in the two vari- eties, respectively. The increase amplitudes of Jizishu 1 were higher than Jishu 21 in the above indexes. Antioxidant enzyme activities were higher in seedling roots of Jisl^u 21 and Jizishul under drought stress than normal treatments; and among them, POD activity was the highest, while PPO activity was the lowest in all an- tioxidant enzymes. The increases of SOD, POD, APX and PPO activities in Jishu 21 were twice of those in Jizishul. The bands of SOD3, POD2, CAT1, APX2 and PPO2 changed obviously between the drought treatments of the two varieties. [Con- clusion] In conclusion, stronger drought tolerance in sweetpotato results in lower in- crease amplitudes of H202 content, formation rate of 02- and contents of Vc and polyphenols under drought stress, and the activities of antioxidant enzymes are stronger in seeding roots under drought stress; and the differences in antioxidant enzymes are mainly related to the changes of isoenzymes including SOD3, POD2, CAT1. APX2 and PPO2.

Antioxidant and isozyme features of two strains of Laminaria japonica (Phaeophyceae)

Healthy sporophytes of two gametophyte mutants of Laminariajaponica with different heat resistances： kelp 901 （901, with comparatively stronger heat-resistance） and Rongcheng No. I （RC, sensitive to heat stress）, were respectively collected during October to December 2002 from Yantai and Rongcheng Sea Farm in the Shandong Peninsula of China. The contents of some biochemical materials and antioxidant capacity were analyzed under controlled laboratory conditions to identify if there is any relation between the overall antioxidant capacity and the heat-resistance in L. japonica and to understand possible mechanism of heat-resistance. Results show that： （1） the overall antioxidant capacity in healthy sporophyte of 901, such as vitamin E, polyphenol, and ascorbic acid contents and the enzymatic activity of SOD, POD, CAT, Gpx, PPO, and PAL, were not always higher than that of RC under controlled laboratory conditions, and no significance （P〉0.05） was shown in total antioxidant capacity （T-AOC） in 901 and RC. Result suggested that the difference in antioxidant capacity was not a decisive factor for different heat-resistances in L. japonica; （2） the simultaneous assay on isozymes was carried out using vertical polyacrylamide gel electrophoresis （PAGE）. Considerable differences in peroxide （PRX）, malate dehydrogenase （MDH）, malic enzyme （ME）, polyphenol oxidase （PPO） and glutamate dehydrogenase （GDH） were obtained in 901 and RC from either the band number, relative mobility （Rf）, or staining intensity, and ME could be used as an indicator to distinguish healthy sporophyte of 901 and RC under controlled laboratory conditions.

Effects of UV-B irradiation on isoforms of antioxidant enzymes and their activities in red alga Grateloupia filicina(Rhodophyta)

Macroalgae in a littoral zone are inevitably exposed to UV-B irradiance. We analyzed the effects of UV-B on isoenzyme patterns and activities of superoxide dismutase （SOD）, peroxidase （POX）, catalase （CAT）, and ascorbate peroxidase （APX） of red algae Grateloupia filicina （Lamour.） C. Agardh. The activities of SOD, CAT, and APX changed in response to UV-B in a time- and dose-dependent manner. POX activity increased significantly under all three UV-B treatments. The enzymatic assay showed three distinct bands of SODI （Mn-SOD）, SODII （Fe-SOD）, and SODIII （CuZn-SOD） under a low （Luv） and medium （Muv） dose of UV-B irradiation, while SODI and SODIII activities decreased significantly when exposed to a high dose of UV-B irradiation （Huv）. The activity of POX isoenzymes increased significantly after exposure to UV-B, which is consistent with the total activity. In addition, a clear decrease in activity of CATIV was detected in response to all the three doses of UV treatments. Some bands ofAPX isoenzyme were also clearly influenced by UV-B irradiation. Correspondingly, the daily growth rate declined under all the three exposure doses, and was especially significant under Muv and Huv treatments. These data suggest that, although the protection mechanisms of antioxidant defense system are partly inducible by UV-B to prevent the damage, G.filicina has incomplete tolerance to higher UV-B irradiation stress.