H2O2预处理对不同水稻品种Cd耐性的影响

 以耐性不同的两个水稻品种N07 63和N07 6为材料,采用水培法研究了镉（Cd）胁迫下过氧化氢（H2O2）预处理对水稻Cd耐性和吸收转运的影响及品种间差异。比较了两个品种不同处理下丙二醛（MDA）、还原型谷胱甘肽（GSH）、非蛋白巯基（NPT）、植物络合素（PCs）含量以及谷胱甘肽硫转移酶（GST）活性的变化。结果表明,50 μmol/L Cd处理显著抑制水稻生长,提高GSH、NPT、PCs、MDA含量和GST活性,且品种间差异显著。从Cd在水稻植株中的分布上看,N07 6向地上部转运的Cd比N07 63多。H2O2预处理后,两个品种Cd毒害效应减轻,GSH、NPT、PCs含量和根部GST活性得到进一步提高,且N07 63的增幅高于N07 6,其耐性也提高更多。H2O2预处理降低了两个品种的Cd向地上部转运,但对根部Cd含量存在不同的影响。从上述结果可以推测,两个品种在Cd解毒机制和对H2O2的响应上存在明显差异。     

Response of Glutathione and Glutathione S-transferase in Rice Seedlings Exposed to Cadmium Stress

A hydroponic culture experiment was done to investigate the effect of Cd stress on glutathione content(GSH)and glutathione S-transferase(GST,EC 2.5.1.18)activity in rice seedlings.The rice growth was severely inhibited when Cd level in the solution was higher than 10 mg/L.In rice shoots,GSH content and GST activity increased with the increasing Cd level,while in roots,GST was obviously inhibited by Cd treatments.Compared with shoots,the rice roots had higher GSH content and GST activity,indicating the ability of Cd detoxification was much higher in roots than in shoots.There was a significant correlation between Cd level and GSH content or GST activity,suggesting that both parameters may be used as biomarkers of Cd stress in rice.     

Physiological Characterization of Zn-efficient Rice （Oryza sativa） Genotype at Different Zn^2＋ Levels

Physiological characteristics of rice at different Zn2+ levels[pZn2+＞11.5, 11.3, 11.0, 10.6, 10. 3, 9.7] were studied with the Zn-efficient rice cultivars IR34, IR36, IR8192, and Zn-inefficient rice cultivars IR26, Ce 64-7, Biyuzaonuo,which grew in chelator-buffered nutrient solution. There were significant differences in tolerance to zinc deficiency among different rice genotypes. Obvious effects of low zinc activity on the physiological characteristic of rice seedlings were noted.There were significant differences in chlorophyll content, photosynthesis rate, MDA concentration in rice leaf, and H+ excretion of root. As pZn2+ decreased, chlorophyll content and photosynthesis rate decreased at a slower pace in Zn-efficient cultivars compared to Zn-inefficient ones, MDA concentration increased slower while H+ excretion of root increased faster in Zn-efficient cultivars than those in Zn-inefficient ones. It was suggested that the above indications could be used as indexes to Zn-efficiency of rice.     

Root Morphology and Anatomy Affect Cadmium Translocation and Accumulation in Rice

Paddy fields contaminated with cadmium (Cd) present decreased grain yield and produce Cd-contaminated grains. Screening for low-Cd-accumulating cultivars is a useful method to reduce the amount of Cd in the grains. The present study aimed to examine the roles of the root morphology and anatomy in Cd translocation and accumulation in rice plants. Twenty-two rice cultivars were used in the first experiment, after which two cultivars [Zixiangnuo (ZXN) and Jinyou T36 (JYT36)] were selected and used in subsequent experiments under hydroponic conditions. The results showed that there were significant differences in Cd concentrations in the shoots (ranging from 4 to 100 mg/kg) and the Cd translocation rates (shoot/root) (from 7% to 102%) among the 22 cultivars, and the shoot Cd concentration was significantly correlated with the Cd translocation rate of the 22 cultivars under 0.1 mg/L Cd treatment. Compared with cultivar ZXN, JYT36 had greater root Cd uptake and accumulation but lower shoot Cd accumulation and Cd translocation rate. The number of root tips per surface area of cultivar ZXN was greater than that of JYT36, while the average root diameter was lower than that of JYT36. Compared with ZXN, JYT36 had stronger apoplastic barriers, and the Casparian bands and suberin lamellae in the root endodermis and exodermis were closer to the root apex in both the control and Cd treatments, especially for suberin lamellae in the root exodermis with Cd treatments, with a difference of 25 mm. The results also showed that, compared with ZXN, JYT36 had greater percentages of Cd bound in cell walls and intracellular Cd but lower Cd concentrations in the apoplastic fluid under the Cd treatment. The results suggested that Cd translocation, rather than root Cd uptake, is a key process that determines Cd accumulation in the rice shoots. The root morphological and anatomical characteristics evidently affect Cd accumulation in the shoots by inhibiting Cd translocation, especially via the apoplastic pathway. It was possible to pre-screen low-Cd-accumulating rice cultivars on the basis of their root morphology, anatomical characteristics and Cd translocation rate at the seedling stage.     

镉胁迫对不同水稻基因型植株生长和抗氧化酶系统的影响

 以籽粒镉积累水平不同的两种品种（丙97252，低积累型；秀水63，高积累型）为材料，研究了镉胁迫对水稻植株生长和抗氧化酶系统的影响。采用水培试验，镉处理设0.0、0.1、1.0和5.0 μmol/L 4个水平。结果表明，镉胁迫抑制植株生长和叶绿素合成，改变植株丙二醛（MDA）含量和超氧物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）活性。在抗氧化酶活性上，根和地上部对镉胁迫的反应存在着差异。总体上，SOD、CAT和POD活性随镉水平的提高而减少，而MDA含量则表现相反。根和地上部MDA含量随着培养液中镉浓度提高而增加，且增加幅度秀水63明显大于丙97252。与对照相比，生长在5.0 μmol/L Cd处理下的植株， SOD活性在孕穗期下降46%~52%，在分蘖期仅下降13%~19%。高浓度镉胁迫下，两品种在MDA含量的增加幅度和叶绿素含量的降低幅度上表现不同，显示出它们对镉的耐性存在着差异。     

Purification and Identification of Glutathione S-transferase in Rice Root under Cadmium Stress

Cadmium (Cd) contamination in paddy soils poses a serious threat to the production and quality of rice.Among various biochemical processes related to Cd detoxification in rice,glutathione S-transferase (GST) plays an important role,catalyzing Cd complexation with glutathione (GSH) and scavenging reactive oxygen species (ROS) in cells.In this study,a hydroponic experiment was conducted to investigate the response of GST isozymes in rice roots upon Cd exposure.Results showed that the GST activity in rice roots was clearly enhanced by 50 μmol/L Cd treatment for 7 d.The GST isozymes were purified by ammonium sulphate precipitation,gel filtration chromatography and affinity chromatography.After being separated by SDS-PAGE and visualized by silver staining,GSTU6 was identified by in-gel digestion,MALDI-TOF-MS analysis and peptide mass fingerprint.The results confirm the vital function of tau class rice GST in Cd detoxification.     

持续高温胁迫对茄子幼苗几个主要生理指标的影响

为了明确持续高温胁迫对不同耐热性茄子品种(系)主要生理指标影响的异同,特采用7份耐热性不同的茄子材料,分别进行2、4、6 d高温处理及6 d高温处理后恢复处理,未高温处理苗做对照,研究了高温胁迫对SOD和POD抗氧化酶活性、AsA和GSH含量,MDA和可溶性蛋白含量以及O.-2产生速率、H2O2含量的影响。结果表明:高温处理2 d和4 d时,SOD和POD抗氧化酶活性、AsA和GSH含量增加,相应的O.-2产生速率、H2O2含量下降;6 d时SOD活性、AsA和GSH含量有所降低,O.-2产生速率、H2O2含量上升,POD活性在热敏感品种(系)继续大幅增加。随高温胁迫时间延长MDA含量不断增加,可溶性蛋白含量变化不大。另外,对各生理指标与热害指数和膜相对电导率的相关性分析结果表明,热胁迫6 d时AsA含量及热胁迫2 d时的O.-2产生速率、H2O2含量与热害指数和相对电导率相关显著,可以作为鉴定不同品种耐热性的参考指标。     

水稻锌营养高效基因型的生理特性

采用HEDTA螯合缓冲营养液培养法,研究了水稻锌营养高效基因型IR34、IR36、IR8192和锌敏感基因型IR26、测64 7、碧玉早糯在不同锌离子活度（pZn2+>11.5,11.3, 11.0, 10.6, 10.3, 9.7）下的生理特性。结果表明,锌离子活度在对不同水稻基因型秧苗生理特性影响上有明显的区别,其中叶绿素含量、光合速率、MDA含量和根系H+分泌量差异比较明显。在供锌水平较低情况下,水稻锌营养高效基因型叶绿素含量下降速度慢,光合速率降低幅度小,MDA含量升高的幅度小,根系能分泌更多的H+,这些指标可以作为衡量水稻锌营养效率的指标。     

不同锌效率水稻基因型及其杂种一代幼苗生长和抗氧化酶活性对Zn2+活度的反应

  为了解水稻耐低锌能力基因型差异的生理机制及F1杂种的耐低锌能力以提高水稻锌效率,解决水稻锌缺乏问题,选用耐低锌基因型水稻IR8192、IR36,锌敏感基因型水稻Ce 64、IR26及杂交后代IR36×IR8192、IR36×IR26和Ce 64×IR26为材料,进行低锌(pZn2+ 11.0)和正常锌(pZn2+ 9.7)营养液培养。结果表明：1)亲本和F1幼苗的株高,叶鞘高,地上部和地下部干质量及锌含量,叶片的叶绿素含量、超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性、丙二醛(MDA)含量在pZn2+ 11.0与pZn2+ 9.7条件下的相对值可作为耐低锌基因型水稻的筛选指标;2)在低锌条件下所有亲本及F1各项指标变化趋势相同,但IR8192、IR36、IR36×IR8192、IR36×IR26的叶绿素含量、SOD酶活性降幅较小,POD、CAT、APX活性升幅较大,MDA含量升幅较小,表明上述基因型水稻的耐低锌能力更强。 低锌胁迫下POD、CAT、APX活性增强,可以更有效地清除活性氧,SOD活性则最先下降;3)除根长、APX活性外,在低锌条件下,IR36×IR8192、IR36×IR26各项指标变化幅度均表现出超亲优势,而Ce 64×IR26则表现出偏中亲优势,推测水稻的耐低锌特性主要受基因的显性效应控制,并存在基因的叠加效应,可以通过耐低锌亲本间的杂交获得具有更强耐低锌能力的水稻基因型。     

盐胁迫下野生大豆叶片中Na+、Cl-积累导致活性氧伤害

以耐盐性强弱不同的野生大豆(JWS耐盐性强，N23232耐盐性弱)为材料，采用砂培试验研究了NaCl胁迫下野生大豆叶片中Na^ 、Cl^-含量及活性氧代谢的变化。结果表明，盐胁迫下供试两种群野生大豆叶片Na^ 、Cl^-含量增加，N23232比JWS更明显；耐盐性弱的N23232叶片O2^-产生速率和H2O2含量上升，膜脂过氧化产物MDA和电导率迅速上升，其叶片中Na^ 、Cl^-含量变化与O2^-、H2O2、MDA和电导率增加呈极显著或显著正相关，而O2^-产生速率和H2O2含量上升与MDA和电导率变化呈极显著正相关。表明在NaCl胁迫下，由于Na^ 、Cl^-在叶片中的积累而导致了活性氧的积累，活性氧诱发膜脂过氧化、破坏膜结构，导致膜结合酶H^ -ATPase和H^ -PPase活性降低，膜透性增加。耐盐种群JWS在盐胁迫下Na^ 、Cl^-积累量少、活性氧水平较低，对膜系统伤害少，膜结合酶活性高，因而能维持液泡膜正常的代谢功能，可能是其耐盐性强的原因之一。     

干旱胁迫下NO对水稻日本晴叶片生理特性的影响

研究干旱胁迫下一氧化氮(Nitric oxide,NO)对水稻叶片光合速率、相对含水量及抗氧化系统的影响,旨在揭示NO增强水稻耐旱性的作用机制。以常规粳稻日本晴为材料,在土培条件下于水稻分蘖盛期叶面喷施硝普钠(SNP,NO缓释剂)和/或cPTIO(NO清除剂)后进行干旱处理,6d后,取样并分析叶片各生理指标。结果表明,与清水对照相比,干旱胁迫下,喷施100μmol/L SNP可显著增强水稻耐旱性,叶片表现出较高的相对含水量和光合速率,较低的丙二醛和过氧化氢含量。相反,100μmol/L cPTIO处理的水稻叶片光合速率明显低于对照,相对含水量略低于对照,而丙二醛和过氧化氢含量显著高于清水对照。进一步研究表明,干旱胁迫下喷施外源SNP的叶片具有较高的超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性,较低的抗坏血酸(AsA)含量和总谷胱甘肽(GSH+GSSH)含量。此外,外源喷施SNP对水稻叶片过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)活性影响不大,各处理间差异不显著。总之,以100μmol/L SNP作为NO缓释剂处理的水稻干旱损伤较轻,干旱胁迫下叶片具有较高的SOD及CAT活性,这可能是NO增强水稻耐旱性的主要原因。     

Identification of QTLs for Cadmium Tolerance During Seedling Stage and Validation of qCDSL1 in Rice

Cadmium(Cd)is a non-essential toxic metal that is harmful to plants.To investigate the genetic mechanism of Cd tolerance in rice,quantitative trait loci(QTLs)associated with Cd tolerance at the seedling stage were analyzed using a recombinant inbred line(RIL)population derived from a cross between PA64s and 93-11.A total of 36 QTLs associated with shoot length,root length,shoot dry weight,root dry weight and total dry weight were detected in Hangzhou and Lingshui of China.Among them,15 QTLs were identified under the control condition and 15 QTLs were identified under the Cd stress condition,and 6 QTLs for Cd tolerant coefficient were detected on chromosomes 1,3,7 and 9.The qCDSL1.1 and qCDSL1.2 were identified in Hangzhou and Lingshui,respectively,and had overlapping intervals on chromosome 1.To further confirm the effects of qCDSL1.1 and qCDSL1.2,we developed a chromosome segment substitution line(CSSL),CSSLqCDSL1,in 93-11 background harboring qCDSL1.1/qCDSL1.2 from PA64s.Compared to 93-11,CSSLqCDSL1 had increased shoot length under the Cd stress condition.These results pave the way for further isolation of those genes controlling Cd tolerance in rice and marker-assistant selection of rice elite varieties with Cd tolerance.     

铬(Cr~(6+))胁迫对不同基因型小麦种子萌发及幼苗抗氧化和渗透调节的影响

为明确小麦种子萌发对Cr~(6+)胁迫响应的品种间差异及其Cr~(6+)耐性差异的生理机制,以耐Cr~(6+)品种扬麦16和Cr~(6+)敏感品种豫麦51为材料,研究了不同浓度的Cr~(6+)(0、10、50、100、150μmol·L~(-1))处理对种子萌发、α-淀粉酶活性、幼苗生长、活性氧水平、抗氧化酶活性和渗透调节物质含量的影响。结果表明,10mol·L~(-1) Cr~(6+)处理下,小麦种子的萌发过程未受到明显影响。随着Cr~(6+)处理浓度的进一步增加,小麦种子发芽势、发芽率、根长逐渐下降,扬麦16受抑制的程度较豫麦51轻;种子α-淀粉酶活性、根系可溶性蛋白和可溶性糖含量呈现先升后降的趋势;根系游离脯氨酸、丙二醛、O_2~和H_2O_2含量逐渐升高。相同浓度Cr~(6+)处理下,扬麦16的种子α-淀粉酶活性、根系可溶性糖和游离脯氨酸含量显著高于豫麦51,而根系丙二醛、O_2~和H_2O_2的含量显著低于豫麦51。在Cr~(6+)胁迫下,小麦根系SOD、POD、APX和GR的活性总体上呈现先升后降的趋势。在高浓度Cr~(6+)(150mol·L~(-1))处理下,扬麦16的种子α-淀粉酶、根系SOD、POD、APX和GR活性受抑制程度均明显小于豫麦51。     

镉胁迫下水稻SOD活性和MDA含量的变化及其基因型差异

以4个水稻品种为材料,采用土培试验,研究了不同土壤镉浓度对水稻超氧化物歧化酶（SOD）活性和丙二醛（MDA）含量的影响,水稻叶片SOD活性和MDA含量在生育进程中的变化,以及SOD活性和植株镉含量的关系。结果表明： 1）轻度镉胁迫有利于提高水稻的SOD活性,而高浓度镉胁迫对水稻的SOD活性有抑制作用;MDA含量与SOD活性存在负相关关系,随着土壤镉浓度的增加,MDA含量先下降后上升。2）在水稻生育过程中,SOD活性分蘖期>乳熟期>齐穗期;MDA含量随生育期一直增加。3）镉胁迫对水稻叶片SOD活性的影响存在基因型差异,分蘖期不同水稻基因型间SOD活性的差异最大。4）水稻的SOD活性与植株和稻米的镉含量呈负相关,齐穗期的SOD活性与镉含量的相关性达显著水平。     

镉浓度对不同玉米品种幼苗生长及生理特性的影响

以玉米品种郑单958、豫单9953、正大999、京农科728为试验材料,采用实验室水培方式,设置不同Cd浓度(0、3、6、9 mg/L),研究Cd胁迫9 d后4个玉米品种苗期生长指标及相关生理指标的差异,利用主成分分析和隶属函数法进行耐Cd性综合评价。研究结果表明,Cd对4个玉米品种苗期的株高、根长、地上部鲜重、地下部鲜重、地上部干重、地下部干重总体上起抑制作用,对根数影响较小。随着Cd胁迫浓度的升高,郑单958、豫单9953和京农科728的总叶绿素含量呈现下降的趋势,正大999呈先上升后下降的趋势。在Cd处理下,相比郑单958和正大999,京农科728和豫单9953的POD活性较对照升高更明显,且MDA含量受影响较小。根据主成分分析和隶属函数法得到4个玉米品种耐Cd能力强弱顺序为京农科728>豫单9953>郑单958>正大999。     

盐胁迫浓度和胁迫时的温度对水稻耐盐性的影响

 在水培条件下，用5种不同浓度的NaCl溶液对20个水稻品种的3~4叶期幼苗进行盐胁迫处理，10 d后考查不同品种单株盐害级别、苗高、茎叶干重和根系Na[sup]+[/sup]/K[sup]+[/sup]含量比等性状。结果表明，0.5%的NaCl胁迫下，品种间的盐害级别和根系Na[sup]+[/sup]/K[sup]+[/sup]含量比差异最大；0.8%的NaCl胁迫下，品种间的相对苗高和相对茎叶干重差异最大。其中韭菜青、农林72、80 85、洞庭晚籼和丁旭稻为强耐盐水稻品种；Pokkali、IR26、小白芒、勐旺谷、明恢63为耐盐或中度耐盐品种。进一步选择8个耐盐性不同的水稻品种，在3种温度条件下进行苗期耐盐性鉴定，发现在相对低温[昼/夜为(23±3)℃/(15±1)℃\]时，水稻生长缓慢，不同品种的盐害级别和根系Na[sup]+[/sup]/K[sup]+[/sup]含量比均较低；在温度较高[昼/夜为(36±1)℃/(26±2)℃\]时，水稻生长加快，不同品种的盐害级别和根系Na[sup]+[/sup]/K[sup]+[/sup]含量比均增高；只有在适温条件[昼/夜为(30±2)℃/(24±2)℃\]下，水稻生长较快，品种间的盐害级别和根系Na[sup]+[/sup]/K[sup]+[/sup]含量比差别最明显。提出在适温条件下，以0.5%或0.8%的NaCl浓度进行水稻品种耐盐性的筛选和耐盐特性的遗传研究比较合适。     

不同类型水稻品种对白背飞虱忌避性、抗生性和耐害性的测定

 研究了19个不同类型的水稻品种对白背飞虱的忌避性、抗生性和耐害性的测定。4个粳稻品种(91-17、丙90-98、丙850和丙93-63对成虫表现出较强的忌避性,丙93-63对白背飞虱产卵具有明显的忌避性。协优9308和春江06对白背飞虱的抗生性最强,协优413对白背飞虱具有一定的抗性。     

外源钙对镍胁迫下水稻幼苗抗氧化酶活性及膜脂过氧化的影响

研究了外源钙（Ca2+）对镍胁迫下水稻叶片组织超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）和抗坏血酸过氧化物酶（APX）的活性、H2O2和丙二醛（MDA）含量以及质膜电解质渗透的影响,以探讨钙缓解植物镍毒性的生理机制。0.1 mmol/L镍（Ni2+）胁迫下水稻叶片组织SOD、CAT和APX活性明显下降,POD活性明显上升,H2O2和MDA含量、电解质渗漏率显著增大,说明镍诱导了细胞发生明显的氧化损伤和膜脂过氧化;钙提高了镍胁迫下叶片组织中SOD、CAT、POD和APX活性,显著降低了H2O2、MDA含量和电解质渗漏率,且10 mmol/L Ca2+处理的抗氧化酶活性上升的程度和H2O2、MDA含量和电解质渗漏率下降的程度比5 mmol/L Ca2+处理的大。提示钙通过促进镍胁迫下水稻叶片组织抗氧化酶活性,增强活性氧清除能力,维持细胞膜结构的稳定,是钙减轻镍对水稻毒性的生理机制之一。     

Proteomic Study for Responses to Cadmium Stress in Rice Seedlings

A proteomic approach including two-dimensional electrophoresis and mass spectrometric (MALDI-TOF MS) analyses was used to investigate the responses to cadmium (Cd) stress in seedlings of rice (Oryza sativa L.) varieties Shanyou 63 and Aizaizhan. Cd stress significantly inhibited root and shoot growth, and affected the global proteome in rice roots and leaves, which induced or upregulated the expression of corresponding proteins in rice roots and leaves when rice seedlings were exposed to 0.1 or 1.0 mmol/L Cd. The Cd-induced proteins are involved in chelation and compartmentation of Cd, elimination of active oxygen free radicals, detoxification of toxic substances, degradation of denatured proteins or inactivated enzymes, regulation of physiologic metabolism and induction of pathogenesis-related proteins. Comparing the Cd-induced proteins between the two varieties, the β-glucosidase and pathogenesis-related protein family 10 proteins were more drastically induced by Cd stress in roots and leaves of Aizaizhan, and the UDP-glucose protein transglucosylase and translational elongation factor Tu were induced by 0.1 mmol/L Cd stress in roots of Shanyou 63. This may be one of the important mechanisms for higher tolerance to Cd stress in Shanyou 63 than in Aizaizhan.     

镉胁迫对苎麻吸收积累镉的影响

本研究通过盆栽试验探索了不同镉浓度对9个苎麻品种吸收积累重金属镉的影响。结果表明,Cd对苎麻生物量、Cd含量和积累量等有显著影响,且浓度越高,影响程度越大。石阡竹根麻、宜春红心麻和川苎1号三个品种在Cd浓度23-46 mg/L下的地上部生物量均高于对照;Cd浓度为23、46、91和182 mg/L时,苎麻地上部Cd平均含量分别为22.93,37.22,71.27和88.08 mg/kg。苎麻地上部Cd积累量品种间差异显著,品种富顺青麻和中苎1号在不同镉浓度处理下表现了较好的适应能力和吸收能力。在镉污染地区种植高耐高吸收的苎麻品种既可用于生态修复,又能获得一定的经济效益。