镉胁迫对小麦叶片细胞膜脂过氧化的影响

镉胁迫使植物体内活性氧自由基清除系统的功能降低,造成细胞内H₂O₂积累,抗坏血酸过氧化酶和谷胱甘肽还原酶活性下降,内源抗氧化剂抗坏血酸和谷胱甘肽含量减少,小麦叶片的组织自动氧化速率显著提高。细胞内丙二醛的积累表明,膜脂过氧化发生和膜系统受到损伤。推测小麦镉伤害过程中,活性氧自由基代谢失衡造成的膜脂过氧化起着重要作用。     

Response mechanism of Chlamydomonas reinhardtii to nanoscale bismuth oxyiodide (nano-BiOI): Integrating analysis of mineral nutrient metabolism and metabolomics

Nanoscale bismuth oxyiodide (nano-BiOI) is widely studied and applied in environmental applications and biomedical fields, with the consequence that it may be deposited into aquatic environments. However, the impact of nano-BiOI on aquatic ecosystems, especially freshwater microalga, remains limited. Herein, the nano-BiOI was synthesized and its response mechanism towards microalga Chlamydomonas reinhardtii was evaluated. Results showed that a low concentration of nano-BiOI (5 mg/L) could stimulate algal growth at the early stage of stress. With the increase in concentration, the growth rate of algal cells was inhibited and showed a dose effect. Intracellular reactive oxygen species (ROS) were significantly induced and accompanied by enhanced lipid peroxidation, decreased nonspecific esterase activity, and significantly upregulated glutathione S-transferase activity (GST) activity. Mineral nutrient metabolism analysis showed that nano-BiOI significantly interfered with the mineral nutrients of the algae. Non-targeted metabolomics identified 35 different metabolites (DEMs, 22 upregulated, and 13 downregulated) under 100 mg/L BiOI stress. Metabolic pathway analysis demonstrated that a high concentration of nano-BiOI significantly induced metabolic pathways related to amino acid biosynthesis, lipid biosynthesis, and glutathione biosynthesis, and significantly inhibited the sterol biosynthesis pathway. This finding will contribute to understanding the toxicological mechanisms of nano-BiOI on C. reinhardtii.     

Effect of cadmium on photosynthetic pigments, lipid peroxidation, antioxidants, and artemisinin in hydroponically grown Artemisia annua

The effects of different cadmium (Cd) concentrations (0, 20, 60, and 100 μmol/L) on hydroponically grown Artemisia annua L. were investigated. Cd treatments applied for 0, 4, 12, 24, 72, 144, 216, and 336 hr were assessed by measuring the changes in photosynthetic pigments, electrolyte leakage, malondialdehyde (MDA) and antioxidants (ascorbic acid and glutathione), while the artemisinin content was tested after 0, 12, 144, 216, and 336 hr. A significant decrease was observed in photosynthetic pigment levels over time with increasing Cd concentration. Chlorophyll b levels were more affected by Cd than were chlorophyll a or carotenoid levels. The cell membrane was sensitive to Cd stress, as MDA content in all treatment groups showed insignificant differences from the control group, except at 12 hr treatment time. Ascorbic acid (AsA) content changed slightly over time, while glutathione (GSH) content took less time to reach a maximum as Cd concentration increased. Cd was found to promote synthesis and accumulation of artemisinin, especially at concentrations of 20 and 100 μmol/L. In conclusion, Cd stress can damage to photosynthetic pigments, and vigorously growing A. annua showed a strong tolerance for Cd stress. Appropriate amounts of added Cd aided synthesis and accumulation of artemisinin.     

两种不同镉富集能力油菜品种耐性机制

利用水培试验研究了不同浓度镉(cadmium,Cd)胁迫条件下(0、2和5 mg·L~(-1))两种Cd富集能力油菜品种[秦油1号(QY-1)和三月黄(SYH)]生长状况与Cd富集特征的差异,并从Cd亚细胞区隔化和抗氧化酶活性等角度探索了两种油菜Cd富集能力的差异机制,并通过田间试验进行验证.结果表明,水培条件下,这两种油菜在Cd胁迫下生长均未受到明显的抑制.在低浓度Cd(2 mg·L~(-1))处理下,两种油菜地上部Cd含量无显著差异,在高浓度Cd(5 mg·L~(-1))胁迫下SYH的地上部和根部Cd含量均显著高于QY-1,分别提高32. 05%和99. 57%,同时其根部生物富集系数(BCF)也较QY-1显著提高.对两种油菜叶片中Cd亚细胞区隔化研究结果表明,随着Cd处理浓度的增加,QY-1和SYH叶片中Cd在热稳定蛋白和镉富集颗粒组分的分布分别提高了143. 69%、118. 91%和63. 34%、118. 91%,由此可见将Cd区隔在热稳定蛋白和镉富集颗粒体等重金属解毒组分是油菜在亚细胞水平上的重要解毒机制.同时,高浓度Cd胁迫下SYH叶中Cd在细胞碎屑组分的含量达QY-1的4. 41倍,可知Cd在细胞碎屑组分中的分布是导致两种油菜Cd富集能力差异的重要机制.结合对两种油菜抗氧化酶活性研究结果,发现抗氧化酶系统可能是QY-1应对高浓度Cd胁迫的重要解毒机制,而SYH则更多地通过将Cd区隔在金属低活性的亚细胞组分来减轻其毒性.田间试验结果验证表明,SYH地上部和地下部Cd含量均显著高于QY-1,分别是QY-1的2. 34和1. 43倍.综上所述,SYH具有更高的Cd提取量和富集能力,具有应用于中轻度Cd污染农田修复的潜力.     

Study on the sensitivity to cadmium of marine fish Salaria basilisca（Pisces： Blennidae）

The present study tested the sensitivity of Salaria basilisca to water-cadmium (Cd) contamination. For this purpose, liver somatic index (LSI), Cd concentrations and the activities of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were measured in the liver of S. basilisca exposed to Cd-contaminated water (2 mg Cd/L as CdCl2) for 14 and 28 d. The results showed that the LSI decreased significantly after 14 and 28 d of Cd-exposure. Cd bioaccumulation in the liver resulted in an increasing uptake up to 42 g/g dry weight after 28 d of exposure. Activities of CAT and SOD were significantly increased with increasing exposure time. A significant increase in GSH-Px activity, under Cd influence, was observed during 14-day exposure period (p < 0.0001). However, a significant decrease (p < 0.05) in this activity with respect to control fish was registered after 28 d of Cd-exposure. These results showed that Cd accumulation in the liver of S. basilisca could induce oxidative stress as demonstrated by changes in the antioxidant enzyme activities. Results also emphasized that S. basilisca may considered as a sensitive species to Cd exposure.     

蒌蒿(Artemisia selengensis)对土壤中镉的胁迫反应及修复潜力研究

以洞庭湖湿地新发现的Cd高富集植物——蒌蒿(Artemisia selengensis)为试验材料,采用盆栽方式,系统研究了蒌蒿在生长期内对Cd的性状反应及富集特征.结果表明,大于40mg.kg-1的Cd胁迫对蒌蒿叶片伤害明显,且导致生物量下降,但植株在100mg.kg-1胁迫下可完成生活史,对Cd有较强的耐受能力;土壤中有效态Cd的含量仅占土壤全Cd含量的15.3%～37.1%;相同胁迫浓度下,各生长阶段的植株体内Cd含量差别不大,但由于生物量的原因,幼苗期对Cd的提取量显著小于其他时期,其中40～60mg.kg-1的Cd处理可使蒌蒿地上部分Cd含量达492～588mg.kg-1(成株期),且植株对该浓度范围的Cd污染去除效果最好;蒌蒿可作为对湿地土壤Cd污染较理想的修复植物加以研究和利用.     

泥蚶不同组织器官对重金属(Cu、Pb、Cd)的富集规律

通过室内半静态暴毒试验,研究三种重金属(Cu、Pb、Cd)的单一与联合胁迫作用下,泥蚶(Tegillarca granosa)不同组织器官对重金属的富集能力、富集途径,以及两两重金属之间的交互作用。结果发现:单一胁迫条件下,泥蚶各组织器官对Cu的富集能力是鳃>内脏团>肌肉,对Pb和Cd的富集能力是鳃>肌肉>内脏团;肌肉和鳃对Pb的富集速率显著(P<0.05)高于内脏团,即泥蚶对Pb的富集可以通过鳃的呼吸作用和体表的渗透作用两条途径实现。联合胁迫条件下,Cd能够拮抗Cu的富集;一定量的Cu也能够在内脏团中发挥作用,拮抗Pb和Cd的累积;在其他各组织中累积的Cu和Cd则不影响Pb的累积,说明Cd和Cu在泥蚶体内以可溶形式存在,而Pb以不溶形式存在。重金属的富集与金属种类、金属浓度、累积途径、生物体的解毒机制等等多种因素有关。     

镉铅复合胁迫下根表铁锰氧化胶膜厚度对美洲商陆富集镉的影响

为了探讨根表铁锰氧化胶膜厚度及共存离子铅(Pb)对美洲商陆富集镉(Cd)影响,采用水培的方法,诱导培育了胶膜厚度具有极显著差异的美洲商陆(低膜美洲商陆、中膜美洲商陆和高膜美洲商陆),分别进行低Cd低Pb、低Cd高Pb、高Cd低Pb、高Cd高Pb等4种不同金属组合的胁迫处理,观察美洲商陆生长状况、测定植株对Cd的富集量、抗胁迫生理活性物质的表达量.结果表明:中膜和高膜美洲商陆侧根发达,新生根较多,高Cd胁迫对根系发育有较强的抑制作用.高Cd条件下,植株对Cd的富集量为高膜美洲商陆中膜美洲商陆低膜美洲商陆,高膜美洲商陆Cd总富集量可达89765.69 mg·kg-1(以干重计).低Cd条件下,植株对Cd的富集量为低膜美洲商陆高膜美洲商陆中膜美洲商陆.高Pb处理,可提高低膜和高膜美洲商陆Cd富集量,但显著降低中膜美洲商陆Cd富集量.根系分泌的可溶性还原糖含量、叶及根部合成的可溶性蛋白含量与根表铁锰氧化胶膜的厚度成正相关.中膜和高膜美洲商陆叶片及根部可溶性蛋白含量还受到不同金属组合胁迫的影响.镉铅复合胁迫使美洲商陆叶片及根部可溶性蛋白含量极显著高于对照组.     

硒对镉胁迫下菠菜生理特性、元素含量及镉吸收转运的影响

为了探讨硒(Se)对菠菜中的镉(Cd)胁迫造成毒害的缓解作用,采用盆栽试验,研究了不同浓度Se(0、0.5、2.0、4.0 mg·L-1)对不同浓度Cd(0.5和2.0 mg·kg-1)胁迫下菠菜生理特性、元素含量及Cd吸收转运的影响.结果表明:不同浓度的Se可使丙二醛(MDA)积累量显著降低,最佳作用下分别为两种浓度Cd单一胁迫下的53.93%和41.79%;不同浓度的Se可以缓解Cd胁迫对菠菜地上部和根部的抑制作用,最佳缓解条件下,菠菜地上部和根部的鲜重分别为两种浓度Cd单一胁迫时的1.13倍、1.29倍和1.31倍、1.37倍,干重分别为1.78倍、2.09倍和3.03倍、4.36倍;叶绿素含量显著提高,在最佳缓解浓度下分别是两种浓度Cd单一胁迫时的1.51倍和1.35倍;与两种浓度Cd单一胁迫相比,最佳缓解浓度下超氧化物歧化酶(SOD)活性分别提高了36.0%和42.8%;外源Se可以使地上部和根部的K、Na、Ca和Mg等元素的含量不同程度的增加;施Se可以有效的抑制菠菜根部对Cd的吸收、富集和向地上部的转运,使菠菜地上部和根部Cd含量显著降低,分别为两种浓度Cd单一胁迫下的65.77%、75.92%和46.11%、70.01%,表明外源Se能有效的减轻Cd胁迫对菠菜的毒害作用.对本研究所用的两种浓度Cd来说,最佳的缓解浓度为2.0 mg·L-1和4.0 mg·L-1.     

P对小麦Cd和As吸收与转运的影响

为了探究磷（P）对小麦幼苗镉（Cd）和砷（As）吸收转运生理机制的影响,通过水培试验,以百农207为供试材料,研究了Cd和As胁迫条件下,外源供P和缺P处理对小麦幼苗生长、根系形态、光合参数、抗氧化系统、离子含量和根茎转移系数的影响.结果表明,与缺P处理相比,外源P供应显著增加As胁迫下小麦幼苗叶绿素的含量,促进根系的生长发育,提高了生物量,而对Cd胁迫下小麦幼苗的生长影响不显著.外源P供应时显著增加了Cd胁迫条件下根系的P和Cd含量,降低了地上部的P和Cd含量;同时显著提高了As胁迫条件下地上部的P和As含量以及As向地上部的转移系数.因此,供P与否对小麦幼苗Cd和As毒害的影响表现出明显的差异性;As胁迫时,外源供P提高了As向地上部的转运能力以及根系的CAT活性,降低了As对小麦的毒害,从而促进了小麦幼苗生物量的累积;而在Cd胁迫条件下,P与Cd之间表现出一定的协同效应,外源供P在一定程度上加重了Cd对小麦的毒害效应.     

不同光强下镉胁迫对紫茉莉光合作用和抗氧化系统的影响

通过土培实验,比较分析了3种光强(全光照(HL)、50%全光照(ML)和10%全光照(LL))下镉胁迫(30 mg·kg-1)对紫茉莉植株生长、光合作用、光合色素、镉、镁、铁和钾含量、脂质过氧化、抗氧化酶活性、抗坏血酸和谷胱甘肽含量的影响.结果发现,镉胁迫显著降低紫茉莉叶片的净光合速率,对HL植株的抑制程度高于ML和LL植株;HL和LL植株最大光化学效率在镉胁迫下显著降低,而ML植株所受影响不明显;镉胁迫显著提高了紫茉莉叶片的暗呼吸速率,ML植株提高幅度最大.镉胁迫对紫茉莉植株生长的抑制作用显著,对HL植株的抑制最大.镉胁迫显著增加了紫茉莉叶片的镉含量,减小叶片叶绿素、类胡萝卜素、Mg、Fe和K的含量,对HL植株影响最大.镉胁迫下,HL植株超氧化物歧化酶和过氧化物酶活性增强,过氧化氢酶和抗坏血酸过氧化物酶活性降低,谷胱甘肽和抗坏血酸含量减小,过氧化氢和丙二醛含量、超氧阴离子产生速率增高,电解质渗漏加重.上述结果表明,镉加重了叶片氧化胁迫程度和强化了对紫茉莉生长的抑制,特别在高光强条件下.     

接种丛枝菌根真菌对雌雄美洲黑杨吸收铅镉的影响

以雌雄美洲黑杨(Populus deltoides)为研究对象,砂培条件下,研究接种丛枝菌根真菌(Glomus intraradices)对受Pb污染(200 mg·kg-1)、Cd污染(10 mg·kg-1)及复合污染的雌雄美洲黑杨Pb和Cd的富集与分配特征的影响,关注Pb/Cd复合污染独特的环境效应.结果表明:1未接种丛枝菌根真菌条件下,与单一污染相比,复合污染增加了美洲黑杨雄株叶、粗根、细根Pb和Cd含量;复合污染增加了雌株叶片中Pb和Cd含量,却降低了粗根和细根中Pb和Cd含量;复合污染条件下雄株Pb和Cd向地上部分器官的迁移率分别增加135%和78%,雌株则分别增加52%和18%.2复合污染条件下,接种丛枝菌根真菌引起雄株Pb和Cd富集系数分别增加87%和6%,雌株则分别增加171%和65%;雄株Pb和Cd向地上部分器官的迁移率降低65%和69%,雌株则分别降低59%和53%.3Pb污染条件下,接种丛枝菌根真菌的雌雄之间Pb积累量没有显著差异;Cd污染条件下,接种丛枝菌根真菌的雄株总Cd积累量是雌株的1.7倍;复合污染条件下,接种丛枝菌根真菌的雌株Pb和Cd总积累量分别是雄株的1.3和1.2倍.本研究表明,接种G.intraradices能提高美洲黑杨的Pb和Cd积累能力,对于不同污染条件下,应根据实际情况选择合适的杨树性别进行造林和生态修复.     

镉在三色堇中的积累及亚细胞与化学形态分布

通过营养液培养实验,研究了在不同Cd浓度(0、0.01、0.05、0.1、0.2、0.3、0.4 mmol·L-1)处理下,三色堇地下部和地上部中Cd的含量与积累特征,进一步分析了Cd在三色堇体内的亚细胞分布特征和化学形态分布特征.结果表明,三色堇体内Cd积累量随着Cd浓度的增加而不断增加,对Cd具有很高的积累能力,是一种潜在的Cd超富集植物.三色堇地下部和地上部大部分的Cd分布在可溶组分和细胞壁中,而在细胞器中的分布较少.随着Cd处理浓度的增加,地下部细胞壁中镉的分配比例呈增加趋势.植株中大部分的Cd以乙醇提取态和水取提态存在,随着Cd处理浓度的增加,地上部中活性强、毒性较高的乙醇提取态和水提取态Cd分配比例总和减少,而活性较弱、毒性较低的氯化钠提取态和醋酸提取态Cd分配比例增加,这有利于降低总镉的相对毒性.因此,液泡区隔化、细胞壁固持和化学形态转化可能是三色堇应对Cd胁迫的重要耐性机制.     

Interactive effects of water and controlled release urea on nitrogen metabolism,accumulation, translocation,and yield in summer maize

To investigate the interactive effects of water and N from controlled release urea (CRU) on N metabolism, accumulation, translocation, and yield in Zhengdan958 (a summer maize cultivar planted widely in China), three water levels (adequate water W3, mild water stress W2, severe water stress W1) and four amounts of CRU (N) (N0, N1, N2, and N3 were 0, 105, 210, and 315 kg N ha^?1, respectively) were carried out under the waterproof shed and soil column conditions. The results showed that yield, N metabolism, accumulation, and translocation were significantly affected by water, CRU, and their interactions after tasseling. Yields showed an increasing trend in response to N rates from 100.2 to 128.8 g plant^?1 under severe water stress (W1), from 124.7 to 174.6 g plant^?1 under mild water stress (W2), and from 143.7 to 177.0 g plant^?1 under adequate water conditions (W3). There was an associated optimum amount of N for each water level. Under W1 and W2, N3 treatments showed significant advantages in three N metabolism enzymes’ activities and the N accumulations, and yield and its components were highest. But the nitrogen harvest index (NHI) of N3 had no significant difference with other nitrogen treatments. Under W3, the N translocation efficiency (NTE) and N translocation conversion rate (NTCR) of N2 in stem and leaf were higher than those of N3, but the N metabolism enzymes’ activities and yields of N2 and N3 had no significant difference, which indicated that N2 was superior to N3. The N3 treatment under W2 and N2 under W3 increased the N accumulation capacity in maize grain as well as the N translocation to grain that contributed to the increase of 1000-gain weight and grains per ear after tasseling. Under this experimental condition, a CRU rate of 225 kg ha^?1 was the best treatment when the soil moisture content was 75 ± 5% of field capacity, but an N rate of 300 kg ha^?1 was superior when soil moisture content was maintained at 55 ± 5% of field capacity during the entire growing season.     

Interactions of zinc and cadmium toxicity in their effects on growth and in antioxidative systems in tomato plants (Solanum lycopersicum)

The interaction between zinc and cadmium was investigated in tomato plants (Solanum lycopersicum). Ten-day-old seedlings were treated with 10 μmol/L CDC12 associated to different concentrations of ZnC12 (10, 50, 100, and 150 μmol/L). Zn supply clearly reduced Cd accumulation in leaves and simultaneously increased Zn concentration. Cd induced oxidative stress in leaves as indicated by an increase in thiobarbituric acid-reactive substances (TBARS) level and chlorophyll breakdown. Furthermore, compared with control, Cdtreate plants had significantly higher activities of superoxide dismutase (SOD, EC 1.15.1.1), whereas, catalase (CAT, EC 1.111.1.6),ascorbate peroxidase (APX, EC 1.11.1.11), and glutathione reductase (GR, EC 1.6.4.2) activities were significantly suppressed by Cd addition. Zn supplementation, at low level, restored and enhanced the functional activity of these enzymes (SOD, CAT, APX and GR) as compared to Cd-alone-treated plants. The beneficial effect of adequate Zn level on Cd toxicity was confirmed by a significant decrease in TBARS level and restoration of chlorophyll content. However, when Zn was added at high level in combination with Cd there was an accumulation of oxidative stress, which was higher than that for Cd or excess Zn alone treatments. These results suggested that higher Zn concentrations and Cd are synergistic in their effect on plant growth parameters and oxidative stress.     

Interactions of zinc and cadmium toxicity in their effects on growth and in antioxidative systems in tomato plants （Solanum lycopersicum）

The interaction between zinc and cadmium was investigated in tomato plants (Solanum lycopersicum). Ten-day-old seedlings were treated with 10 mol/L CdCl2 associated to di erent concentrations of ZnCl2 (10, 50, 100, and 150 mol/L). Zn supply clearly reduced Cd accumulation in leaves and simultaneously increased Zn concentration. Cd induced oxidative stress in leaves as indicated by an increase in thiobarbituric acid-reactive substances (TBARS) level and chlorophyll breakdown. Furthermore, compared with control, Cdtreated plants had significantly higher activities of superoxide dismutase (SOD, EC 1.15.1.1), whereas, catalase (CAT, EC 1.111.1.6), ascorbate peroxidase (APX, EC 1.11.1.11), and glutathione reductase (GR, EC 1.6.4.2) activities were significantly suppressed by Cd addition. Zn supplementation, at low level, restored and enhanced the functional activity of these enzymes (SOD, CAT, APX and GR) as compared to Cd-alone-treated plants. The beneficial e ect of adequate Zn level on Cd toxicity was confirmed by a significant decrease in TBARS level and restoration of chlorophyll content. However, when Zn was added at high level in combination with Cd there was an accumulation of oxidative stress, which was higher than that for Cd or excess Zn alone treatments. These results suggested that higher Zn concentrations and Cd are synergistic in their e ect on plant growth parameters and oxidative stress.     

Generation of low-cadmium rice germplasms via knockout of OsLCD using CRISPR/Cas9

The OsLCD gene, which has been implicated in cadmium (Cd) accumulation in rice, might be a useful target for CRISPR/Cas9 editing. However, the effects of OsLCD gene editing on Cd accumulation, plant growth, and yield traits remain unknown. Here, we used CRISPR/Cas9 to generate oslcd single mutants from indica and japonica rice cultivars. We also generated osnramp5 single mutants and oslcd osnramp5 double mutants in the indica background. When grown in Cd-contaminated paddy soils, all oslcd single mutants accumulated less Cd than the wild types (WTs). Consistent with this, oslcd single mutants grown in Cd-contaminated hydroponic culture accumulated significantly less Cd in the shoots as compared to WTs. This decrease in accumulation probably resulted from the reduction of Cd translocation under Cd stress. Oxidative damage also decreased, and plant growth increased in all oslcd single mutant seedlings as compared to WTs in the presence of Cd. Plant growth and most yield traits, as well essential element concentrations in rice seedling shoots, brown rice, and rice straw, were similar between oslcd single mutants and WTs. In the presence of Cd, Cd concentrations in the brown rice and shoots of oslcd osnramp5 double mutants were significantly decreased compared with WTs as well as osnramp single mutants. Our results suggested that OsLCD knockout may reduce Cd accumulation alone or in combination with other knockout mutations in a variety of rice genotypes; unlike OsNramp5 mutations, OsLCD knockout did not reduce essential element contents. Therefore, OsLCD knockout might be used to generate low-Cd rice germplasms.     

Piriformospora indica confers cadmium tolerance in Nicotiana tabacum

Piriformospora indica, a root-colonizing endophytic fungus of Sebacinales, promotes plant growth and confers resistance against biotic and abiotic stresses. In order to confirm the influence of P. indica on growth, proline, malondialdehyde (MDA), chlorophyll, and cadmium (Cd) amounts in Nicotiana tabacum under Cd stress, hydroponics, pot and field trials were conducted. The results showed that P. indica can store Cd in plant roots and reduce leaf Cd content, reduce the concentration of MDA, and increase the proline and chlorophyll content and the activities of catalase, peroxidase, and superoxide dismutase under hydroponic Cd stress. RT-PCR analysis showed that the relative expression level of genes Gsh2, TaPCS1, oas1, GPX, and Hsp70 in colonized plants was 4.3, 1.4, 2.9, 1.7, and 6.9 fold higher than in un-colonized plants respectively. Cd exposure significantly reduced un-colonized plants'' agronomic traits compared to P. indica-colonized ones. Our results suggested that P. indica can sequester Cd in roots, so that much less cadmium was transported to leaves, and the increased concentrations of antioxidant enzymes, pigments and proline contents, as well as the higher expression of stress-related phytochelatin biosynthesis genes in P. indica-inoculated plants, may also serve to protect N. tabacum plants against oxidative damage, enhancing Cd tolerance.     

硅对过量锰胁迫下水稻根系抗氧化系统和膜脂质过氧化作用的调控机理

揭示Mn胁迫下Si对水稻根系抗氧化系统的影响机制,可为减轻水稻Mn毒害提供重要的理论依据和技术支持.因此,本研究通过水培试验,采用两个对Mn耐性不同的水稻品种,研究Si(1.5 mmol·L-1)对Mn(2 mmol·L-1)胁迫下水稻根系抗氧化系统的影响.结果表明,在Mn胁迫下,敏感品种新香优640(XXY)根系的超...     

田间施用锌肥对小麦籽粒镉累积的影响及施用风险

锌（Zn）和镉（Cd）的交互作用是近年来小麦Cd污染防治的重要研究方向.以华北地区典型小麦田为研究对象,通过田间试验,探究Zn肥对土壤-小麦系统Cd污染的控制效果和施用风险.结果表明,低用量Zn处理下,济源和开封两地小麦籽粒Cd含量均呈下降趋势,与对照相比下降幅度分别为33.4%和25.3%.高用量Zn处理下,两地小麦籽粒Cd含量不降反升,与低用量Zn处理下小麦籽粒Cd含量相比增幅为22.4%和34.2%.施Zn后两地土壤Zn总量和有效态含量均有显著升高,且造成了土壤Cd的部分活化.典型相关分析（CCA）显示,当土壤ω（Zn）小于200 mg ·kg^-1时,土壤Zn是土壤-小麦系统Cd富集的主要影响因子,而当土壤ω（Zn）大于200 mg ·kg^-1时,土壤Cd的活化是影响小麦籽粒Cd富集的主要原因.回归分析显示土壤Cd/Zn降至0.0089时（低用量Zn）,Zn和Cd表现出拮抗效应,土壤Cd/Zn降至0.0078时（高用量Zn）,Zn和Cd表现出协同效应.针对区域Cd污染特征,调整Zn肥用量可以提高污染防治效率并避免加剧Cd污染危害.