重金属Cd2+、Pb2+胁迫对小白菜生理及其BcMT2a基因表达的影响

为探明小白菜对Cd~(2+)、Pb~(2+)单一及其复合胁迫的响应机理,以不同浓度Cd~(2+)、Pb~(2+)处理小白菜幼苗,对其生物量、生理指标(POD、SOD、CAT活性及MDA含量)及Cd~(2+)、Pb~(2+)在小白菜中的富集情况进行研究,同时克隆与重金属富集相关的金属硫蛋白基因BcMT2a并对其表达特异性进行分析。结果表明:除低浓度Cd~(2+)(10mg/L)对小白菜的根长和地上部分生长有一定的促进作用外,Cd~(2+)、Pb~(2+)及Cd~(2+)—Pb~(2+)处理对小白菜根长和地上部分生长均有一定的抑制作用,且随着浓度的升高,抑制作用逐渐增强;抗氧化酶系统中,POD与SOD活性较高,且与CAT活性均呈现先升后降的趋势。Cd~(2+)浓度为40mg/L时,MDA含量达到最大值。Cd~(2+)、Pb~(2+)在小白菜各组织中的积累顺序依次为根茎叶,且Pb~(2+)在一定程度上能够促进Cd~(2+)的吸收。BcMT2a基因编码的蛋白主要存在于细胞核中,属于易突变亲水性蛋白,该基因的相对表达量在一定浓度范围内可随着Cd~(2+)、Pb~(2+)及Cd2—Pb~(2+)浓度的升高而增加,且相对表达量的趋势与抗氧化酶系统结果基本一致,说明小白菜在受到Cd~(2+)、Pb~(2+)及Cd~(2+)—Pb~(2+)胁迫时,抗氧化酶系统与BcMT2a基因有明显的应答,可增加小白菜对Cd~(2+)、Pb~(2+)的耐受性。     

硫对大豆生长发育及生理效应影响的研究

采用砂培试验研究了硫素对大豆营养生长、营养元素吸收、氮硫比值和光合作用强度及酶活性等生理效应影响。结果显示,正常供硫能保证大豆生长发育和生理生化反应;不同生长关键时期低硫处理对大豆营养生长和生理效应均有一定不利影响。特别是苗期缺硫明显降低大豆生物量和营养元素的吸收,叶面积生长量不足,叶片中叶绿素含量下降,硝酸还原酶活性下降,硝态氮含量增加,氮代谢受阻,氮硫比值提高,严重影响大豆的正常生长发育。     

水洗处理对秸秆生物质炭吸附解吸Cd2+和Pb2+的特性影响

水洗处理在不影响生物质炭性质的前提下,可以去除附着在其表面的热解副产物,从而保证对重金属离子的去除能力。以小麦和玉米秸秆为原料,比较两种秸秆类生物质炭对溶液Cd2+和Pb2+的吸附解吸特点及其水溶性盐分含量的影响。结果表明,小麦和玉米秸秆生物质炭对Cd2+和Pb2+的吸附过程均更好地符合准二级动力学方程和Langmuir方程。小麦秸秆生物质炭对Cd2+和Pb2+的最大吸附量达12.82 mg g?1和9.91 mg g?1,为玉米秸秆吸附量的1.31 ~ 1.76倍和1.06 ~ 1.53倍。洗脱水溶性盐分可以降低生物质炭对Cd2+和Pb2+的吸附,水洗后小麦秸秆和玉米秸秆生物质炭对Cd2+的最大吸附量分别降低42.36%和60.13%,对Pb2+的最大吸附量分别降低29.47%和62.72%。水洗处理提高了两种秸秆生物质炭对Cd2+和Pb2+的解吸率,其中小麦秸秆生物质炭提高幅度较大,由原来对Cd2+的解吸率为1.84% ~ 13.05%提高到7.88% ~ 20.19%,对Pb2+的解吸率为1.57% ~ 11.82%提高到6.34% ~ 16.94%。因此,可溶性盐分在秸秆生物质炭吸附Cd2+和Pb2+的过程中具有重要作用,该研究结果将为制备高效修复重金属污染土壤的生物质材料提供技术支撑。     

甲基叔丁基醚和Cd复合作用对小麦幼苗生理指标的影响

以小麦为试验对象,通过水培试验研究不同浓度的MTBE(0,5,10,50,100,200,300,400,500mg/L)和Cd(5mg/L)复合作用对小麦幼苗叶绿素含量、可溶性蛋白、抗氧化酶系统活性、MDA和游离脯氨酸含量的影响。结果表明:叶绿素含量和可溶性蛋白的含量随着MTBE浓度升高出现先增高后降低的趋势;抗氧化酶系统(SOD、POD)和游离脯氨酸的趋势是一致的,在MTBE浓度为400,500mg/L时,SOD酶活性与对照相比降低了17%,18%,POD酶活性降低了26.8%,27.8%;在MTBE浓度为200,300,400,500mg/L时,MDA含量与对照相比有显著差异(P<0.05),分别降低了27.5%,30.6%,34.9%,36.7%;游离脯氨酸的含量在MTBE浓度为200mg/L时高于对照62.3%。     

EGCG与Cd2+对前列腺癌细胞PC-3生长的抑制作用研究

采用MTT法检测了EGCG、Cd2+及二者相互作用对PC-3细胞生长的抑制作用;通过倒置显微镜观察了前列腺癌细胞PC-3形态的变化;采用细胞凋亡罗丹明123染色试剂盒检测了PC-3细胞凋亡;利用ESR法检测了PC-3细胞膜流动性的改变。结果表明,EGCG与Cd2+都可抑制前列腺癌细胞的生长;二者都可改变细胞的外观形态;80 µmol/L的EGCG处理并未观察到凋亡的PC-3细胞,20 µmol/L的Cd2+处理主要导致PC-3细胞坏死,而80 µmol/L EGCG与20 µmol/L Cd2+共存可诱导细胞凋亡;同时,EGCG参与的处理都降低了PC-3细胞膜的流动性。     

几种铵盐对土壤吸附Cd2+和Zn2+的影响

采用平衡吸附法,研究了不同铵盐对潮褐土、红壤吸附Cd2+、Zn2+的影响。结果表明,土壤对Cd2+、Zn2+的吸附量随平衡溶液中Cd2+、Zn2+浓度的增加而增加;潮褐土和红壤对Cd2+、Zn2+的最大吸附量为:Zn2+ Cd2+,且潮褐土红壤;随NH4HCO3浓度的增加,两种土壤对Cd2+、Zn2+的吸附率显著提高,NH4Cl、NH4NO3和(NH4)2SO4抑制红壤对Cd2+、Zn2+的吸附及潮褐土对Cd2+的吸附,对潮褐土Zn2+的吸附率影响不显著;铵盐浓度相同时,红壤对Cd2+吸附率为:NH4HCO3NH4ClNH4NO3≈ (NH4)2SO4,红壤对Zn2+吸附率为:NH4HCO3NH4Cl NH4NO3(NH4)2SO4。     

磁流体改性制备磁性肉骨生物炭及其对Cd2+的吸附特性

病死水产品(以非正常死亡鲤鱼为例)制成肉骨生物炭(Carp meat bone Biochar,CBC)应用于Cd2+污染修复,是实现水产养殖废弃物无害化、减量化和资源化处置的新途径.采用磁流体对CBC进行改性制备磁性肉骨生物炭(Magnetic Carp meat bone Biochar,MCBC),并考察磁流体改...     

Cd2+处理对几种叶菜可食部分Cd含量及品质的影响

以5种叶菜为材料,采用水培和盆栽试验2种培养方式,测定不同浓度Cd2+处理下叶菜地上部(可食部分)生物量、Cd含量、硝酸盐及纤维素含量等生理与品质指标。结果表明:水培与盆栽培养条件下青菜、塌地乌、小白菜、菠菜及芥菜5种叶菜生物量随着Cd2+处理浓度增加显著降低(P0.05);可食部Cd含量显著升高(P0.05);高浓度水培与盆栽Cd2+处理(40mg.L-1和70mg.kg-1)下,5种叶菜中菠菜Cd含量相对较高,青菜Cd含量较低;随着Cd2+处理浓度增加,5种叶菜硝酸盐及纤维素含量升高,维生素C和可溶性糖含量下降,采用灰度关联综合分析表明,不同浓度Cd2+处理的5种叶菜中,青菜品质相对稳定及Cd含量较低,为Cd低积累品种。     

Cd胁迫对3种蕨类植物生理代谢及镉累积特性的影响

通过盆栽试验,对Cd胁迫下3种蕨类植物江南卷柏(Selaginella moellendorffii)、紫萁(Osmunda japonica)和蜈蚣草(Pteris vittata)的生长、生理和重金属累积与分布情况进行研究。结果表明,在较高浓度Cd处理下,3种植物的株高、鲜重和地上与地下部分的干重比都受到抑制,浓度越高,抑制越明显;随着Cd处理浓度的增加,3种蕨类植物叶绿素含量随胁迫浓度的增加先上升后下降;MDA含量均有不同程度的增加,在Cd浓度≥50mg/kg,与对照相比,江南卷柏和蜈蚣MDA含量增加不明显(p0.05),而紫萁MDA含量显著增加(p0.05);脯氨酸含量均随处理浓度的增加而增大;江南卷柏和紫萁SOD活性均随处理浓度的增加先升高(Cd=50mg/kg,达到最大值)后降低,蜈蚣草SOD活性随处理浓度的增加而增大;江南卷柏和紫萁POD活性随处理浓度的增加而增大,蜈蚣草POD活性随处理浓度的增加而先上升后下降,在Cd浓度为100mg/kg时达到最大值;3种蕨类植物CAT活性总体上随胁迫浓度的增加先上升后下降。在Cd浓度≤50mg/kg时,紫萁对重金属Cd的累积能力最强,但在高浓度镉胁迫时,紫萁的耐性要低于江南卷柏和蜈蚣草。综合各个指标变化情况来看,3种蕨类植物对重金属Cd的抗性排序为江南卷柏蜈蚣草紫萁。     

赤泥对Cd污染稻田水稻生长及吸收累积Cd的影响

采用田间小区试验,研究了不同赤泥施用量对酸性Cd污染稻田（潮泥田）水稻生长及吸收累积Cd的影响。结果表明,赤泥施用量为4 948 kg·hm-2时水稻产量达到最高,其主要作用是促进了水稻有效穗的形成。同时施用赤泥能显著提高土壤pH,降低土壤有效态Cd含量和减少水稻Cd累积。与不施赤泥的对照相比,施用赤泥3 000 kg·hm-2的处理水稻增产12.4%（P〈0.05）,水稻根Cd降低22.0%（P〈0.05）,糙米Cd（0.14 mg·kg-1）降低40.8%（P〈0.01）,并达到国家粮食卫生标准（GB2715—2005）;当赤泥施用量增至9 000 kg·hm-2时,土壤pH提高12.0%（P〈0.01）,有效态Cd含量降低24.9%（P〈0.05）,水稻根系、茎叶和糙米Cd分别降低55.7%（P〈0.01）、54.5%（P〈0.01）和69.9%（P〈0.01）。表明利用赤泥修复中轻度酸性Cd污染土壤是可行的,并能起到改良土壤和促进水稻增产的效果。试验所用赤泥重金属含量很低,不会造成二次污染。但将赤泥大面积应用于酸性Cd污染稻田还需要系统研究应用参数,并采取农机配套和激励机制来鼓励农民自发行动的积极性。     

Soybean (Glycine max) Extracts Impact on Plant and Soil Biology

The aim of the present investigation was to determine the phytotoxic effect of aqueous extract from fresh and oven-dried leaves and roots of soybean plants on maize growth and on rhizosphere soil. The extract prepared from fresh leaves of drought-stressed soybean plants significantly increased the accumulation of proline, soluble sugar, and endogenous abscisic acid (ABA) content of maize-treated plants. Increase in antioxidant activity like superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), and endogenous ABA was recorded in treated plants. The soybean leaf extracts prepared from drought-stressed plants significantly decreased the soil pH and electrical conductivity (EC) of maize cultivated soil. The soybean drought-stressed leaf extracts prepared plants were found more effective in modulating the physiology of maize, indicating the higher allelopathic potential of soybean.     

Soybean (Glycine max) cell wall composition and availability to feed enzymes

Defatted untoasted soybean cotyledons and hulls were fractionated as water solutes (WSc and WSh) and water unextractable (WUc and WUh). Further fractionation of WUc through deproteinization yielded the isolation of a water unextractable solid (WUS) fraction that was mainly composed (molar percent) of galactose (28.1%), glucose (27.8%), arabinose (13.3%), and uronic acids (17.6%), which accounted for 76% of the water insoluble polysaccharides in soybean cotyledons (WUc). The cell wall (WUS) was sequentially fractionated with chelating agents (chelating agent soluble solids, ChSS) and a gradient of agents (dilute alkali, DASS; 1 M alkali, 1MASS; and 4M alkali, 4MASS), which gave a final cellulosic residue. The ChSS and DASS extracts were characterized as pectin-rich fractions, whereas 1MASS and 4MASS were hemicellulose- and cellulose-rich fractions. Incubation in vitro of the WUc fraction with pectinase, cellulase, and xylanase resulted in the release of low amounts (not more than 5% bound basis) of monosaccharides, mostly uronic acids, xylose, and arabinose. Protein extraction hardly increased this release after enzymatic incubation (<7%). However, progressive fractionation of the cell wall matrix markedly increased the release of monosaccharides from pectin- (ChSS and DASS) and hemicellulose-rich fractions (1MASS and 4MASS). Significant degradation of cellulose (up to 20%) was achieved only after complete protein, pectin, and hemicellulose extraction.     

Nitrogen Fixation,Ureide, and Nitrate Accumulation Responses to Soybean Aphid Injury in Glycine max

There is little information available about soybean aphid (Aphis glycines Matsumura) effects on the physiology and mineral nutrition of soybean (Glycine max [L.] merr.). Controlled-environment studies were conducted to measure soybean aphid infestation effects on dry weight, nitrogen (N) fixation, ureide-N, and nitrate-N concentration and accumulation. Plants grown in perlite using –N nutrient solution culture were infested at the 3rd trifoliolate (V3) stage and measured for N fixation, nodule characteristics, and ureide-N concentration at the full pod (R4) stage. When compared to uninfested control plants, aphid infestation reduced total nodule volume per plant by 34%, nodule leghemoglobin per plant by 31%, plant N fixation rate by 80% and shoot ureide-N concentration by 20%. Soil-grown plants were infested at the first trifoliolate (V1) stage and shoots were measured for dry weight, nitrate-N, and ureide-N at the full bloom (R2) stage. Infestation reduced shoot dry weight by 63%, increased nitrate-N concentration by 75%, but did not significantly affect ureide-N concentration. Because nutrient concentration is a single-point measurement that results from the integration of two dynamic processes, nutrient accumulation and dry matter production, we conclude that aphid-induced reductions in N fixation, coupled with decreased dry weight accumulation, caused shoot ureide-N concentration to remain unchanged in aphid-injured plants when compared to uninfested plants. Because nitrate-N concentration was greater in aphid-damaged shoot tissue, we further conclude that nitrate-N accumulation was less sensitive to aphid injury than dry weight accumulation.     

大豆抗胞囊线虫4号小种转录组测序及分析

大豆胞囊线虫(soybean cyst nematode,SCN)(Heterodera glycines)是一种世界性的大豆(Glycine max)病害.本研究以抗SCN4号生理小种的黑豆为研究对象,对大豆胞囊线虫侵染后的两个发育时期进行转录组测序和生物信息学分析,宏观了解大豆的抗病机制.通过Illumina HiSeqTM2500测序共获得1.96× 1010 bp的数据.经过分析后,接种后第9天(第一时期)和接种后第17天(第二时期)分别得到2 180个和4 210个差异表达基因,同时,对差异表达基因进行基因本体(Gene Ontology,GO)注释,蛋白质直系同源簇(Clusters of Orthologous Groups of proteins,COG)注释,结果显示,GO注释和COG注释分别将差异表达基因分为了58和25个功能类别.另外,京都基因与基因组百科全书(Kyoto Encyclopedia of Genes and Genomes,KEGG)富集分析结果表明,可将两个时期的差异表达基因分别定位到83和105个具体的代谢途径分支.其中,参与到激素信号转导途径,苯丙氨酸代谢,能量代谢等过程中的差异基因最多,这些数据为进一步筛选抗病关键基因及功能验证等研究提供了依据.     

转基因大豆MON89788基体标准物质的研制

转基因产品成分检测是转基因生物安全管理和标识的重要支撑,而转基因生物标准物质是获得准确、可靠、具有可比性检测结果的保证.转基因大豆(Glycine max) MON89788为我国批准进口用作加工原料的农业转基因生物,因此,制备转基因大豆MON89788基体标准物质是对其进行安全管理所必需的.本研究通过将转基因大豆MON89788和其受体材料A3244分别冷冻研磨成粉末,按质量分数称量配制,得到转基因含量为49.3 g/kg的标准物质.采用方差分析法(F检验法)进行均匀性检验,统计量F值为1.618,小于临界值F(0.05,11,24)标准物质均匀性良好;短期稳定性考察结果表明,标准物质可在常温下稳定储存4周,在-20℃下长期稳定性达到30个月.本批MON89788基体标准物质有两个特性量值,一是基于重量法配比混合的粉末质量分数,量值为49.3 g/kg,扩展不确定度为2.0 g/kg;二是基于qRT-PCR 8家实验室联合定值的转基因DNA与总DNA的质量分数,量值为49.8 ng/μg,扩展不确定度为5.9 ng/μg.本批标准物质每瓶1.0 g,使用时最小取样量为100mg,可用于对转基因大豆MON89788进行定性和定量检测,以及转基因大豆MON89788特异性检测方法的评价和实验室质量控制.本研究为我国转基因检测基体标准物质的研制提供了理论基础和技术支持.     

Responses to sequential exposure to SO2 and salinity in soybean (Glycine max L.)

Soybean plants (Glycine max L. cv. Buchanan) were subjected to one of three levels of salinity preteatment (with electrical conductivities of 0.7, 4.4 and 6.5 dS m^?1) and then exposed to one of three concentrations of SO₂ (1, 145 and 300 bl l ^?1 for 5 h d^?1), or vice versa. Each stress episode lasted 3 weeks. Both salinity and SO₂ deecreased leaf area, root and shoot dry weight and the fresh weight of root nodules. SO₂ induced an increase in the shoot: root ratio and leaf chlorophyll concentrations. Low salinity pretreatment protected plant growth from SO₂ injury, probably by decreasing SO₂ uptake by increasing stomatal resistance. However, high salinity-treated plants, despite also showing stomatal closure, were severely injured by subsequent SO₂ exposure. Prior exposure to SO₂ caused plants to become more vulnerable to salt injury. Plants pretreated with high SO₂ were killed after 12 days of high salt stress. These data suggest that the compensatory mechanisms and predisposition characteristics of salinity and SO₂ largely depend upon the stress levels used.     

镧对UV-B辐射胁迫下大豆幼苗叶绿素含量的影响

采用水培实验方法研究了La对紫外辐射（UV—B2 0．15WM^-2,0．45Wm^-2）胁迫下大豆（Glycine max）幼苗叶绿素含量及叶绿素a／b值的影响。实验结果表明：与CK相比，无UV—B胁迫时20mgL^-1LaCl3能明显提高大豆幼苗的叶绿素含量，且叶绿素a的增幅（12．77％）大于叶绿素b（0．00）；UV—B处理使大豆幼苗叶绿素含量降低，且T2处理（0．45Wm^-2）中的下降幅度（12．18％）大于T1（0．15Wm^-2）处理，叶绿素a的降幅大于叶绿素b。但适量浓度的La溶液有抑制叶绿素含量降低的作用；在叶绿素含量变化动态图中，20mgL^-1LaCl2处理组叶绿素含量均高于CK组，也高于60mgL^-1LaCl3处理组，La＋UV—B处理组叶绿素含量与UV-B处理组走势近似。但降幅小于后者，即La具有提高大豆幼苗叶绿素含量、缓解UV—B辐射伤害的作用。     

Influence of Mercury on Soybean Plants (Glycine max L.) at Low pH

The influence of Hg on soybean plants under different pH conditions and Hg concentrations was studied. Growth inhibition by Hg was higher in roots than the upper part of the plant, but was highly dependant on pH condition. Growth inhibition of roots was observed when Hg concentration was higher than 1 mg Hg L^?1 for pH 4.0 and 5 mg Hg L^?1 for pH 6.0. Using ²⁰³Hg as a radioactive tracer, the amount of Hg (1 mg Hg L^?1) uptake in root was found to be about 1.5 times higher at pH 4.0 than that at pH 6.0; suggesting that Hg when highly accumulated at the lower pH induced inhibition of root growth. Decreased amounts of Hg due to evaporation during the plant growth were very low, but were higher at pH 6.0 than that at pH 4.0. There was hardly any translocation of Hg from roots to the upper parts through the stem within 24 h.