超高产水稻组合‘培矮64S/E32’的耐光氧化特性及其机理

甲基紫精(MV)介导的光氧化导致两个水稻品种‘汕优63’(目前我国大面积推广的杂交水稻)和‘培矮64S/E32’(新培育的超高产杂交水稻)细胞电解质渗漏率都增加,前者增加的量大于后者,显示‘培矮64S／E32’的细胞膜系统受光氧化的伤害小。光氧化条件下,‘培矮64S／E32’仍能维持较高的光合放氧能力(Amax,φi)、PSⅡ活性(Fv/Fm、φPSⅡ)和叶绿素荧光猝灭系数(qP、MPQ),而且光氧化引起‘培矮64S／E32’这些参数的下降幅度也小。另外,光氧化导致了两个水稻品种抗氧化酶SOD和APX活性增加,‘培矮64S／E32’增加的幅度约为‘汕优63’的3倍。结果 表明超高产水稻具有更强的耐光氧化能力。     

针叶树越冬针叶光氧化与叶绿体超氧阴离子自由基

以Tiron为自旋探针,检出了越冬针叶叶绿体指示超氧阴离子自由基产生的TH~·ESR信号。此信号可由紫外辐射,也可由光合有效辐射产生。以单位叶绿素量为基数计算的信号强度比已报道的其它植物材料大2～3个数量级。红松叶绿体信号又大于其它针叶树。此信号可被外源SOD,抗坏血酸、乙醇和N_2抑制;随光照增加而增强,12月到次年5月期间又随时间而增强。上述结果表明红松针叶的冬季光氧化伤害与叶绿体中过量超氧阴离子自由基的产生有关。     

超高产水稻组合‘培矮64S/E32’的耐光氧化特性及其机理

甲基紫精（MV）介导的光氧化导致两个水稻品种‘汕优63’(目前我国大面积推广的杂交水稻)和‘培矮64S/E32’（新培育的超高产杂交水稻）细胞电解质渗漏率都增加,前者增加的量大于后者,显示‘培矮64S/E32’的细胞膜系统受光氧化的伤害小。光氧化条件下,‘培矮64S/E32’仍能维持较高的光合放氧能力（Amax、Φi）、PSⅡ活性（Fv/Fm、ΦPSⅡ）和叶绿素荧光猝灭系数（qP、NPQ）,而且光氧化引起‘培矮64S/E32’这些参数的下降幅度也小。另外,光氧化导致了两个水稻品种抗氧化酶SOD和APX活性增加,‘培矮64S/E32’增加的幅度约为‘汕优63’的3倍。结果表明超高产水稻具有更强的耐光氧化能力。     

光氧化胁迫条件下叶绿体中活性氧的产生、清除及防御

活性氧(ROS)具有双重作用,高浓度引起细胞损伤,低浓度起保护作用。在光氧化胁迫条件下,光合作用高能态的反应与O2丰富供应使叶绿体成为活性氧丰富的来源。当ROS的积累超过抗氧化剂防护系统清除能力,叶绿体及细胞不可逆的光氧化损伤就会出现。而高等植物的质粒是半自主的细胞器,有它们自己的基因组学及转录、翻译机制来控制ROS生成、保护光合作用机构免受光氧化损伤。因此,本文就光氧化胁迫期间,叶绿体中ROS的乍成、功能与防护机制进行了综述。     

兼性CAM植物长叶景天叶片在C3和CAM型时的光氧化作用

通过停止浇水产生水分胁迫使兼性CAM植物长叶景天 (SedumspectabileBoreau)叶片光合途径由C3 型转为CAM型。干旱 15d时观察到典型的CAM生理特征 ,且叶片的δ13 C值与含水量成线性相关。水分胁迫改变了叶绿素荧光参数和抗氧化能力 ,ΦPSⅡ 和qP 降低 5 0 %和 34% ,NPQ提高约 180 % ,SOD活性和清除DPPH·自由基能力也明显下降 ,但膜半透性变化不大。当将处于C3 (浇水 )和诱导为CAM(缺水 )型的叶圆片用外源甲基紫精 (MV)和强光作光氧化处理后 ,与C3 型叶片相比 ,诱导CAM型叶片的NPQ不能提高 ,qP 和ΦPSⅡ 降至很低水平 ,光系统处于高还原态 ,光能供给与消耗失衡 (1-qP=0 .86和 (1-qP) /NPQ >1) ,膜系统几乎失去完整性。这种严重的光氧化损伤表明 ,与我们以前报告的专性CAM植物不同 ,以兼性CAM植物诱导表达的CAM型未能显示比C3 型较强的耐光氧化优势。讨论了出现这种光氧化敏感性差别的可能原因     

兼性CAM植物长叶景天叶片在C3和CAM型时的光氧化作用

通过停止浇水产生水分胁迫使兼性CAM植物长叶景天(Sedum spectabile Boreau)叶片光合途径由C3型转为CAM型.干旱15 d时观察到典型的CAM生理特征,且叶片的δ13C值与含水量成线性相关.水分胁迫改变了叶绿素荧光参数和抗氧化能力,ΦPSⅡ和qP降低50%和34%,NPQ提高约180%,SOD活性和清除DPPH@ 自由基能力也明显下降, 但膜半透性变化不大.当将处于C3(浇水)和诱导为CAM(缺水)型的叶圆片用外源甲基紫精(MV)和强光作光氧化处理后,与C3型叶片相比,诱导CAM型叶片的NPQ不能提高,qP和ΦPSⅡ降至很低水平,光系统处于高还原态,光能供给与消耗失衡(1-qP=0.86和(1-qP)/NPQ>1),膜系统几乎失去完整性.这种严重的光氧化损伤表明,与我们以前报告的专性CAM植物不同,以兼性CAM植物诱导表达的CAM型未能显示比C3型较强的耐光氧化优势.讨论了出现这种光氧化敏感性差别的可能原因.     

低温诱导水稻幼苗的光氧化伤害

通过分析MDA,GSH,Asc和Chl含量及质膜透性,探讨了低温诱导水稻幼苗的光氧化伤害。在5℃、白昼PFD为400μmol m~(-2)s~(-1)对,叶片光氧化伤害随低温处理时间的延长而加强,其程度并随温度下降而加剧;耐冷不同的品种表现也有差异。在昼夜10℃/0℃温度下,叶片光氧化程度随PFD的提高而增强。低温处理后恢复期间,470μmol m~(-2) s~(-1)光强会加剧光氧化伤害,而60μmol m~(-2) s~(-1)光强则有利于伤害的恢复。光是植物冷害研究中不可忽略的环境因子。     

水稻耐光氧化和耐荫特性的生理基础

用简易、有效的人工光氧化和遮荫技术对３０个水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）种质进行筛选,鉴定出既耐光氧化又耐荫、耐光氧化不耐荫、耐荫不耐光氧化、既不耐荫又不耐光氧化等４种品种类型,并用既耐光氧化又耐荫的品种“武育粳３号”和对光氧化和遮荫均敏感的品种“香籼”进行光合特性研究。结果表明：在遮荫条件下,与对光氧化和遮荫敏感的品种“香籼”比较,“武育粳３号”的ＰＳⅡ活性差异不大,ＲｕＢｉｓＣＯ活性降     

早晚季不同耐光氧化特性水稻品种籽粒灌浆关键酶活性变化

选用光氧化敏感和不敏感的两大类型4个水稻品种研究早晚季耐光氧化反应特性与其稻米品质稳定性密切相关的生理生化原因.结果表明,耐光氧化反应特性强的适强光生态型水稻品种的平均灌浆速率(G_mean)、达最大灌浆速率时间(T_max.G)和达最大灌浆速率百粒重(W_max.G)等参数在早晚季灌浆结实期间保持相对稳定;而对光氧化敏感的弱光生态型品种佳禾早占以上参数的早晚季稳定性较差.比较早晚季籽粒灌浆充实过程中关键酶活性的变化结果可见,耐光氧化反应特性强的品种,灌浆速率高峰到灌浆终期ADPG-焦磷酸化酶和淀粉合成酶活性早晚季变异比耐光氧化反应特性弱的品种小,且耐光氧化反应特性强的品种灌浆高峰前后酶活性变异的幅度早晚季也较一致.     

超级杂交稻两优培九及其亲本的光氧化特性

通过比较超级杂交稻两优培九和其亲本的光能利用与活性氧代谢的差异,为培育耐光氧化的杂交稻提供选亲配组的生理依据．使用TPS-光合仪和FMS2荧光仪(Hansateeh,UK)分别测定了人工光氧化处理后水稻叶片的光合速率与叶绿素荧光,同时测定了叶绿素、蛋白质和丙二醛的含量。以及超氧化物歧化酶和过氧化物酶的活性．结果表明,两优培九的光合速率低于母本2．4％,高于父本23％;光氧化处理8d后,与母本相比。两优培九的叶绿素、蛋白质、原初光化学效率、超氧化物歧化酶和过氧化物酶分别高于母本33％、15％、30％、32％和100％;光化学猝灭系数和丙二醛分别低于母本9％和50％。与父本相比,则差异不大．超级杂交稻两优培九在光氧化条件下光能利用率较高,在耐光氧化特性上具有超亲的光合生理特性．     

Enhancement of NADP-malic enzyme in transgenic rice induced the accumulation of reactive oxygen species

It had been demonstrated that the photosynthetic photodamage, such as photoinhibition and photooxidation, was enhanced in transgenic rice plants overexpressing NADP-malic enzyme (ME). However, its physiological base has not been investigated. In order to elucidate the physiological elements contributed to the enhancement of photodamage in NADP-ME transgenic rice plants, some physiological indices related to reactive oxygen species (ROS) accumulation were studied using the T₁ progeny of transgenic rice plants. The results showed that more ROS such as O ₂ ^−. and H₂O₂ were accumulated in transgenic rice plants, which enhanced photooxidation, while the accumulation of malondialdehyde in transgenic rice plants was not evident as compared with the wild-type plants. The measurement of NADPH/NADP ratios in leaves showed that transgenic rice plants had a higher ratio than untransformed rice plants. Based on these data, we speculated that overexpression of NADP-ME led to the deficiency of NADP and overreduction of photosystem I, which induced the accumulation of ROS in the transgenic rice plants, and just ROS were accounted for plant sensitivity to photooxidation. Published in Russian in Fiziologiya Rastenii, 2006, Vol. 53, No. 3, pp. 364–370. The text was submitted by the author in English.     

水稻耐光氧化和耐荫特性的生理基础

用简易、有效的人工光氧化和遮荫技术对30个水稻(Oryza sativa L.)种质进行筛选,鉴定出既耐光氧化又耐荫、耐光氧化不耐荫、耐荫不耐光氧化、既不耐荫又不耐光氧化等4种品种类型,并用既耐光氧化又耐荫的品种"武育粳3号"和对光氧化和遮荫均敏感的品种"香籼"进行光合特性研究.结果表明:在遮荫条件下,与对光氧化和遮荫敏感的品种"香籼"比较,"武育粳3号"的PSⅡ活性差异不大,RuBisCO活性降低较少,光合能力、光合生产力较高.在光抑制条件下,"武育粳3号"的PSⅡ活性,PSⅡ光化学效率(Fv/Fm),PSⅡ-D1蛋白含量降低较少,光合作用光抑制较轻.在光氧化条件下,内源活性氧清除剂SOD诱导活性高,清除O-能力强,因而叶绿素衰减较慢.上述研究为水稻育种提供了配套的优良生理特性的鉴定技术和生理依据.     

在光氧化条件下不同类型高产稻的叶绿素荧光特性和膜脂过氧化特点

用不同类型高产稻(Oryza sativa L.)粳稻9516、具有粳型成分的两系法亚种间杂交稻培矮64/E32、两优培九(培矮64/9311)和籼型杂交稻X07S/紫恢100、冈优881、汕优63为材料,研究了孕穗期叶片在光氧化条件下的叶绿素荧光特性和膜脂过氧化表现.光氧化处理后,与籼型杂交稻比较,粳稻和具有粳型组分的亚种间杂交稻的PSⅡ原初光化学效率(Fv/Fm)、PSⅡ的线性电子传递的量子效率(ΦPSⅡ)和光化学猝灭系数(qP)下降的较少;超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)诱导的活性较高,活性氧 (O(-)/()2、H2O2)和丙二醛(MDA)的产生积累较少,叶绿素和蛋白质含量下降较少,表现出耐光氧化特性,这与在自然条件下生育后期叶绿素含量变化相一致.相关分析表明它们的耐光氧化特性与结实率密切相关,说明耐光氧化品种抗早衰,有利籽粒充实.这些结果启示我们:从超高产育种出发,兼顾杂种优势利用和抗早衰两方面考虑,在母本不育系中引入粳型成分是一个值得重视的育种策略.     

The anti-photooxidation of anthocyanins-rich leaves of a purple rice cultivar

In the leaf of rice (Oryza sativa L.) cultivar Yunnan purple rice,the anthocyanins with an obvious absorption peak at 530nm were distributed in the cells of upper and lower epidermis,bulliform tissue and bristle. The maximal photosynthetic oxygen evolution rate and chlorophyll content in flag leaves were 28% and 23%,respectively,more than the common green leaf rice cultivar Chijiaoru-anzhan. Higher chlorophyll content is probably one of the physiological adaptations for enhancing light harvesting capacity of the antenna in photosystems in this cyanic leaves species. Upon the photooxidation of leaf segments mediated by methyl viologen in weak light for 3 days,the distinct bleaching of anthocyanins in purple rice was associated with the reduction of scavenging ability to DPPH· free radical ability and the increase in membrane leakage rate. But almost no changes in contents of flavonoids and total phenolics were observed. Chlorophyll fluorescence parameters Fv/Fo,qP and φPSⅡ decreased with the increase in NPQ and DES of xanthophylls cycle after photooxidation treatment. Green rice leaves showed more decrease in DPPH· scavenging rate and more increase in cell membrane leakage rate but showed a trace of anthocyanins during photooxidation. It is sug-gested that anthocyanin may be a beneficial and primary antioxidant in sun cyanic rice leaves against oxidative stress induced by environmental adversity. And photooxidation could induce different changing patterns of anthocyanins between the tested purple and green rice leaves.     

The anti-photooxidation of anthocyanins-rich leaves of a purple rice cultivar

In the leaf of rice (Oryza sativa L.) cultivar Yunnan purple rice, the anthocyanins with an obvious absorption peak at 530nm were distributed in the cells of upper and lower epidermis, bulliform tissue and bristle. The maximal photosynthetic oxygen evolution rate and chlorophyll content in flag leaves were 28% and 23%, respectively, more than the common green leaf rice cultivar Chijiaoruanzhan. Higher chlorophyll content is probably one of the physiological adaptations for enhancing light harvesting capacity of the antenna in photosystems in this cyanic leaves species. Upon the photooxidation of leaf segments mediated by methyl viologen in weak light for 3 days, the distinct bleaching of anthocyanins in purple rice was associated with the reduction of scavenging ability to DPPH · free radical ability and the increase in membrane leakage rate. But almost no changes in contents of flavonoids and total phenolics were observed. Chlorophyll fluorescence parameters Fv/Fo, qP and ϕ_PSII decreased with the increase in NPQ and DES of xanthophylls cycle after photooxidation treatment. Green rice leaves showed more decrease in DPPH · scavenging rate and more increase in cell membrane leakage rate but showed a trace of anthocyanins during photooxidation. It is suggested that anthocyanin may be a beneficial and primary antioxidant in sun cyanic rice leaves against oxidative stress induced by environmental adversity. And photooxidation could induce different changing patterns of anthocyanins between the tested purple and green rice leaves.     

NADH as electron donor for the photosynthetic membrane of Chlamydomonas reinhardii

A chloroplast fraction from Chlamydomonas reinhardii cells can oxidize NADH in the light, unlike chloroplasts of higher plants. The Chlamydomonas preparation catalyzes electron flow from NADH to methylviologen or ferredoxin to evolve hydrogen (in the presence of a hydrogenase) or take up oxygen. The NADH photooxidation is sensitive to rotenone, dibromothymoquinone and dicyclohexylcarbodiimide. This suggests that a rotenone sensitive NADH dehydrogenase is coupled on the plastoquinone reduction site of the potosynthetic electron flow system. On sonication of the particles NADH photooxidation is lost but may be restored by a protein fraction from an acetone extract plus plastocyanin.Abbreviations DAD diaminodurene - DCCD dicyclohexylcarbodiimide - DCMU (3,3-dichlorphenyl)-N·N dimethyl urea - DBMIB dibromothymoquinone - DNP-INT dinitro-phenylether of 2-iodo-4-nitrothymol - MV methylviologen - chl chlorophyll Dedicated to Professor Dr. O. Kandler on the occasion of his 60th birthday     

Solar inactivation of mesophilic Aeromonas by exogenous photooxidation in high-rate algal pond treating waste water

AIMS: Investigations were carried out to observe the effect of sunlight on the survival of mesophilic Aeromonas (A. caviae, A. hydrophila and A. sobria) in high-rate algal pond. METHODS AND RESULTS: Light damage was estimated by loss of bacterial culturability, using simple beaker experiments. Survival of the strains studied under illuminated conditions was highly affected by the physico-chemical conditions within the microcosms. The inactivation of Aeromonas increased strongly as dissolved oxygen was increased, and was dependent on exogenous sensitizers. This process was enhanced by the high pH of water. Die-off of bacteria was prevented by adding catalase and pyruvate (H2O2 scavengers) into the microcosms. CONCLUSIONS: The damage of Aeromonas was mainly due to exogenous photooxidation. Hydrogen peroxide at least was involved in light-induced damage of bacteria. Aeromonas sobria appeared to be slightly less sensitive to photooxidation than A. hydrophila and A. caviae. SIGNIFICANCE AND IMPACT OF STUDY: The present study could explain the relative resistance of A. sobria to treatment in wastewater stabilization ponds.     

自然条件下不同高产稻生育后期剑叶叶绿素荧光和膜脂过氧化的表现

以籼型(Oryza sativa L.)杂交组合汕优63为对照,以中粳9516、两系亚种间杂交组合培矮64S/E32、培矮64S/9311、亚种间三系杂交稻冈优881和两系杂交组合X07S/紫恢100为材料,研究其在生育后期(抽穗-成熟)自然条件下剑叶的叶绿素衰减、CO2交换、叶绿素荧光参数和膜脂过氧化表现.结果表明: 水稻在生育后期伴随叶绿素衰减,其叶内的原初光化学效率Fv/Fm、PSⅡ非环式电子传递效率ΦPSⅡ、电子流传递速率ETR都有相应地下降,这种光能转化的障碍使多余的光能传递给PSⅡ的还原侧,产生O(-)/(*)2累积,发生膜脂过氧化和MDA的积累,引起光合色素及光合膜的破坏,发生光氧化早衰.这种现象在品种间有明显差异,耐光氧化的粳稻9516,其叶内的 Fv/Fm、ΦPSⅡ、ETR、qP下降较少,具有较稳定的光能转化能力,不易早衰,具有较高的结实率;而对光氧化敏感的籼稻汕优63其叶内的Fv/Fm、ΦPSⅡ、ETR,光化学猝灭参数qP下降较多,易发生膜脂过氧化,导致叶片早衰,影响水稻灌浆结实和产量;而二系的和三系的杂交稻的耐光氧化特性和早衰表现居于中间.从水稻超高产育种的角度出发,在目前株型良好的基础上,兼顾杂种优势和防止早衰两方面考虑,在母本中利用粳型或带有粳型基因的不育系是育种上一个值得重视的策略.     

Cultivar Differences in Photosynthetic Tolerance to Photooxidation and Shading in Rice (Oryza Sativa L.)

Forty-four genotypes from the rice germplasm were identified under photoinhibition/photooxidation and shade conditions and divided into four basic types: (1) cultivars tolerant to both photooxidation and shading, (2) cultivars tolerant to photooxidation but sensitive to shading, (3) cultivars tolerant to shading but sensitive to photooxidation, and (4) cultivars sensitive to both photooxidation and shading. Photosynthetic characteristics of a cultivar tolerant (cv. Wuyugeng 3) and a cultivar sensitive (cv. Xiangxian) to photooxidation and shading were compared. The photochemical efficiency (F_v/F_m) of photosystem 2 (PS2) and the content of PS2-D1 protein in the tolerant cultivar Wuyugeng 3 decreased less under photooxidative conditions as compared with Xiangxian. Under similar conditions, superoxide dismutase was induced rapidly to a higher activity and the active oxygen (O^–) built up to a lower level in Wuyugeng 3 than in Xiangxian. Net photosynthetic rate (P _N) decreased by 23 % in Wuyugeng 3 vs. 64 % in Xiangxian. Shading (80 %) during the booting stage caused only small decreases (7–13 %) in ribulose-1,5-bisphosphate carboxylase activity and P _N in Wuyugeng 3 but severe decreases (57–64 %) were observed in Xiangxian which corresponded to the decreases in grain yield of the two cultivars (38 and 73 %, respectively). We described a simple and effective screening method and physiological basis for breeding crops for enhanced tolerance to both high and low irradiance.     

A simple and fast detection technique for arsenic speciation based on high‐efficiency photooxidation and gas‐phase chemiluminescence detection

High‐efficiency photooxidation (HEPO) and gas phase chemiluminescence detection (CL) combined with high‐performance liquid chromatography (HPLC) and hydride generation were developed for speciation of As(III), As(V), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). After chromatography separation, the arsenic species were passed through HEPO which performed efficient photooxidation and converted MMA and DMA to As(V) in several seconds. Then the reaction of ozone and arsine upon hydride generation produced a CL signal as the analytical parameter. The total analytical process was completed within 10 min. The effects of operational parameters such as the concentrations of hydrochloric acid and NaBH₄ solution, carrier gas flow and air gas flow for ozone generation were investigated. Detection limits were 3.7, 10.3, 10.2 and 10.0 µg/L for As(III), As(V), MMA and DMA, respectively. The recoveries of the four arsenic species in human urine sample ranged from 87 to 94%. Copyright © 2009 John Wiley & Sons, Ltd.