A new glucosyltransferase UGT78 from Iris sanguinea is a putative negative regulator in cadmium stress response

Urbanization has resulted in a significant degra-dation of soil quality,subjecting plants to persistent abiotic stressors such as heavy metal pollution,salinization,and drought.UDP-glycosyltransferases(UGTs)participate in protein glycosylation,secondary metabolite synthesis,and detoxification of exogenous toxic substances.Iris sanguinea Donn ex Hornem exhibits a high degree of resistance to various abiotic stressors.To enhance the plant’s response to adversity,a novel glycosyltransferase belonging to the UGT78 family,encoding flavonoid 3-O-glucosyltransferase(UF3GT),was cloned from the monocot species I.san-guinea.Compared with the control group,overexpression of IsUGT78 enhanced sensitivity to cadmium stress,while showing no significant impact under NaCl and d-sorbitol treatments.Under cadmium treatment,arabidopsis exoge-nously transformed with the IsUGT78 gene possessed lower germination,fresh weight,root length,and chlorophyll con-tent and increased malondialdehyde content than the wild type arabidopsis.In addition,metabolomics in leaves led to the identification of 299 flavonoid metabolites,eight and 127 which were significantly up-and down-regulated,respec-tively,in the transgenic plants.Of note,all eight upregulated flavonoid compounds were glycosylated.Given that arabi-dopsis,which exogenously expresses the IsUGT78 gene,has reduced resistance to cadmium,IsUGT78 may lead to a reduced ability to cope with cadmium stress.

Advances in Understanding Cadmium Stress and Breeding of Cadmium-Tolerant Crops

Cadmium(Cd) pollution has emerged as a critical global environmental concern, due to its significant toxicity, environmental persistence, and the pervasiveness of contamination. Significantly, the bioaccumulation of Cd in agricultural crops constitutes a primary vector for its entry into the human diet. This issue warrants urgent attention from both the scientific community and policymakers to develop and implement effective mitigation strategies. This review delves into the physiological impacts of Cd stress on plants, including the suppression of photosynthetic activity, amplification of oxidative stress, and disruptions in mineral nutrient homeostasis. Additionally, the resistance mechanisms deployed by plants in response to Cd stress have been explored, and the prospective contributions of molecular breeding strategies in augmenting crop tolerance to Cd and minimizing its bioaccumulation have been assessed. By integrating and analyzing these findings, we seek to inform future research trajectories and proffer strategic approaches to enhance agricultural sustainability, safeguard human health, and protect environmental integrity.

外源Cd对川芎苓种萌发及幼苗生长的影响

本研究旨在探究不同浓度镉(Cd)对川芎苓种萌发和幼苗生长的影响。采用以石英砂为基质的水培试验,施加不同浓度CdCl 2·2.5 H 2O(0、0.1、0.25、0.5、1、2 mmol/L)溶液处理川芎苓种,研究Cd胁迫对川芎苓种萌发、幼苗生长、生理代谢及Cd含量的影响。结果显示,随着Cd浓度的增加,株高抑制率、根长抑制率上升;根、叶及节盘Cd含量显著升高;株高、根长、叶鲜重、根鲜重下降;抗氧化酶(过氧化氢酶、过氧化物酶、超氧化物歧化酶)活性、非酶系统物质(可溶性蛋白、谷胱甘肽、脯氨酸)含量以及丙二醛含量先升高后降低。研究表明,0.1~2.0 mmol/L Cd对川芎苓种萌发和早期幼苗生长均有明显的毒害作用,随着Cd胁迫浓度的升高毒害作用增强,其中川芎幼苗根对Cd胁迫最敏感。Cd胁迫下川芎幼苗生理生化指标整体上呈现低促高抑的Hormesis效应。川芎幼苗通过提高抗氧化酶活性和非酶系统物质积累,减少膜系统损伤、活性氧蓄积,缓解Cd毒害作用,提高耐受性。

土壤Cd、Pb污染对苣苋草生物量、生理生化特征和Cd、Pb积累特性的影响

【目的】比较两品种苣苋草对Cd、Pb胁迫的生理生化响应的差异性,寻找对Cd、Pb胁迫抗性较强的品种。【方法】采用盆栽试验,研究不同浓度Cd、Pb单一及复合胁迫下‘R104’和‘K472’两品种苣苋草的生物量,Cd、Pb积累特性,渗透调节物质含量和抗氧化酶活性的变化。【结果】两品种苣苋草的生物量在单一Cd胁迫时下降,在低浓度Pb(2.5 g·kg^(-1))胁迫时上升,在高浓度Pb(10.0 g·kg^(-1))胁迫时下降,在Cd、Pb复合胁迫时表现为先上升后下降的趋势。Cd、Pb单一胁迫下,苣苋草的Cd、Pb含量随着相应元素胁迫浓度的增大而上升;Cd、Pb复合胁迫下,苣苋草的Cd、Pb含量随着另一元素胁迫浓度的增大呈先上升后下降的趋势。随着Cd、Pb单一及复合胁迫浓度的增大,苣苋草超氧化物歧化酶(SOD)活性呈先上升后下降的趋势,过氧化物酶(POD)活性逐渐上升,过氧化氢酶(CAT)活性呈抑制效应。Cd、Pb交互作用在苣苋草生物量和SOD活性上总体表现为复合胁迫>单一胁迫;在植物重金属含量上表现为:低浓度Cd与Pb互为促进作用,高浓度Cd与Pb互为拮抗作用。【结论】苣苋草主要通过提高POD活性和维持CAT活性来抵抗Cd、Pb胁迫;‘R104’的抗性大于‘K472’,表明‘R104’更适合在重金属Pb污染的土壤区域推广种植。

好氧堆肥对生物炭理化性质及吸附Cd^(2+)稳定性的影响

生物炭可作为畜禽粪污好氧堆肥中去除重金属的功能材料,但堆体内部复杂的环境变化会影响生物炭的理化性质,从而影响其对重金属吸附的稳定性。将普通秸秆生物炭(BC)和磁性秸秆生物炭(FBC)置于牛粪中进行30 d好氧堆肥试验,研究两种生物炭基本理化性质及对Cd^(2+)吸附稳定性的影响。结果表明:堆肥处理使BC和FBC的比表面积分别增加20.56%和76.64%,总孔容分别下降2.36%和3.70%,平均孔径分别下降19.17%和46.54%,表面官能团发生变化,FBC的饱和磁化强度下降43.67%。堆肥后,饱和吸附Cd^(2+)的两种生物炭BC和FBC的TCLP提取态Cd(TCLP-Cd)占比和TCLP提取液pH(TCLP-pH)均呈下降趋势,其中TCLP-Cd占比分别从28.31%和22.85%显著下降至26.76%和13.85%(P<0.05),TCLP-pH分别从3.66和3.29显著下降至3.51和3.14。综上,堆肥老化改变了两种生物炭的理化性质,降低了其酸可提取态Cd的含量,提高了其吸附Cd 2+的稳定性,且FBC中Cd^(2+)的稳定性更强。

4个品种香石竹(Dianthus caryophyllus)对Cd胁迫的响应及累积转运特征

镉(Cd)是引起土壤污染的常见重金属元素,对生态环境和人体健康危害极大.在中轻度污染区栽培观赏性植物,可为重金属污染土壤安全利用提供可能路径.选取4个香石竹(Dianthus caryophyllus)品种马斯特、理想、凯丝和卡林波,采用盆栽试验,设置高(50 mg·kg^(−1))、中(30 mg·kg^(−1))、低(10 mg·kg^(−1))3个质量分数Cd胁迫,以不添加Cd为对照(CK,0 mg·kg^(−1)),探讨4个品种香石竹对Cd胁迫的响应及其累积转运特征.结果表明,马斯特在不同质量比Cd胁迫下生物量几乎不受影响.45 d时,仅马斯特高Cd质量分数处理叶绿素含量相对值(SPAD)降低8.60%,其余品种均能维持正常.随栽培时间延长,各品种可溶性蛋白(SP)逐渐增加,过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)活性减弱,说明移栽早期植株受重金属Cd胁迫影响,但可通过自身抗氧化酶系统清除多余自由基,逐渐产生抗性.马斯特、理想、凯丝和卡林波地下部富集系数在1.56~12.72、4.63~15.74、3.56~7.98、5.40~8.50范围内,地上部富集系数在0.17~0.73、0.22~1.18、0.10~0.85、0.13~0.63范围内,重金属从地下部向地上部转移能力较弱,故可保护其地上部免受毒害.

Dopamine alleviates cadmium stress in apple trees by recruiting beneficial microorganisms to enhance the physiological resilience revealed by high-throughput sequencing and soil metabolomics

Dopamine has demonstrated promise as a stress-relief substance.However,the function of dopamine in Cd tolerance and its mechanism remains largely unknown.The current study was performed to investigate the mechanism of dopamine on alleviating apple Cd stress through regular application of CdCl2 and dopamine solution to potting soil.The results indicated that dopamine significantly reduced reactive oxygen species(ROS)and Cd accumulation and alleviated the inhibitory effect of Cd stress on the growth of apple plants through activation of the antioxidant system,enhancement of photosynthetic capacity,and regulation of gene expression related to Cd absorption and detoxification.The richness of the rhizosphere microbial community increased,and community composition and assembly were affected by dopamine treatment.Network analysis of microbial communities showed that the numbers of nodes and total links increased significantly after dopamine treatment,while the keystone species shifted.Linear discriminant analysis effect size indicated that some biomarkers were significantly enriched after dopamine treatment,suggesting that dopamine induced plants to recruit potentially beneficial microorganisms(Pseudoxanthomonas,Aeromicrobium,Bradyrhizobium,Frankia,Saccharimonadales,Novosphingobium,and Streptomyces)to resist Cd stress.The co-occurrence network showed several metabolites that were positively correlated with relative growth rate and negatively correlated with Cd accumulation,suggesting that potentially beneficial microorganisms may be attracted by several metabolites(L-threonic acid,profenamine,juniperic acid and(3β,5ξ,9ξ)-3,6,19-trihydroxyurs-12-en-28-oic acid).Our results demonstrate that dopamine alleviates Cd stress in apple trees by recruiting beneficial microorganisms to enhance the physiological resilience revealed.This study provides an effective means to reduce the harm to agricultural production caused by heavy metals.

入侵植物三裂叶薯生物炭对Cd2+的吸附性能研究

以外来入侵植物三裂叶薯(Ipomoea triloba)制备生物炭(IBC),分别于300℃、500℃、700℃限氧条件下制备得到三裂叶薯生物炭(IBC300、IBC500和IBC700),结合FTIR和XRD等手段对IBC在水溶液中Cd^(2+)的吸附特性及机理进行研究。结果表明,IBC对Cd^(2+)的吸附过程符合拟二级动力学方程(R^(2)值为0.868~0.976),以化学吸附为主;Langmuir模型更加适合用于模拟IBC对Cd^(2+)的吸附(R^(2)值为0.982~0.984),说明主要以单分子层吸附为主,为有利吸附。IBC700对Cd^(2+)吸附效果最好。吸附机理以化学吸附为主,具体机理与碳酸盐离子发生络合沉淀反应和官能团的π-π相互作用。

典型矿区周边水田土壤Cd生物有效性研究

为遴选可有效表征农田土壤Cd生物有效性的指标,文章采集浙江某地20组稻米及其协同土壤,分析稻米Cd质量比、土壤的基本理化性质、Cd总质量比、不同浸提态Cd质量比及欧共体标准物质局(European Community Bureau of Reference,BCR)形态。结果表明:稻米Cd质量比为0.01~0.51 mg/kg,土壤Cd质量比为0.17~3.15 mg/kg,稻米Cd富集系数为0.04~1.42;土壤Cd主要以弱酸态(40.5%)和还原态(37.1%)存在,二乙烯三胺五乙酸(diethylenetriaminepentaacetic acid,DTPA)浸提土壤Cd能力最强(15.6%);基于w(CaCl_(2)-Cd)构建的三次函数建立的回归模型可解释稻米Cd 57.4%方差,w(CaCl_(2)-Cd)可以作为表征水稻土壤Cd生物有效性的指标,基于水稻土壤Cd生物有效性可提高污染风险评价的科学性。

Effects of Waterlogging Time on Rice Cd Absorption and Accumulation under Cadmium Stress

A pot experiment with exogenous cadmium was utilized to study the effects of waterlogging time on rice yield and Cd accumulationin different growth stages including top tillering stage and filling stage.The results showed that the rice yields of all flooding treatments were lower than the CK(CI).The WI,T1,T2,T3 and T4 decreased significantly by 23.7%,16.0%,15.5%,20.2%and 18.6%respectively.The Cd content of brown rice decreased with the extension of waterlogging time.And WF was the lowest,at only 3.4%of the wet irrigation of the whole growth period(WI).Under the same waterlogging condition,the Cd content in brown rice with 1 to 4 weeks of flooding treatment at the top tillering stage decreased by 27.1%(P﹤0.05),46.6%(P﹤0.05),56.0%(P﹤0.05)and 35.2%(P﹥0.05)respectively,compared with the treatment at the filling stage.And the average decrease was 41.2%.The variation tendency of Cd content in stems and leaves was similar to brown rice.The translocation efficiency of Cd from stems and leaves to rice seeds decreased with the extension of waterlogging time.The Cd enrichment factor of stems and leaves,as well as brown rice,varied greatly with different treatments.Specifically,the Cd enrichment factors in brown rice and in stems and leaves under WI were 28.0 and 17.8 times higher respectively than those under WF.The findings of this study demonstrated that flooding could inhibit the uptake and accumulation of Cd in rice,with significant positive correlation between them.The inhibition effect of flooding treatment on Cd accumulation in rice at the top tillering stage was superior to that at the filling stage.

外源硫对Cd胁迫下番茄植株生长及抗逆代谢的影响

硫(S)作为植物必须的大量元素在调节植物生长发育及响应非生物胁迫过程中具有重要的作用.本研究以番茄幼苗为材料,探究不同浓度S在Cd胁迫下对番茄植株生长及抗逆代谢的影响.结果表明,在缺S环境下植物生长明显受到抑制且Cd的胁迫效应更加显著,1~4 mmol·L^(-1) S能够显著促进番茄幼苗的生物量累积并缓解由于Cd胁迫导致的生长缓慢现象.外源S显著提升抗逆性物质脯氨酸和可溶性蛋白的含量以缓解Cd胁迫.此外,Cd胁迫导致番茄幼苗氮(N)和磷(P)代谢受阻,植物体内N和P的赋存形式及分布发生明显变化,外源S的添加能够通过调节N代谢和P代谢的关键酶-硝酸还原酶、谷氨酰胺合成酶及酸性磷酸酶活性,促进番茄幼苗N和P的代谢过程,降低Cd对植物的毒性效应.

Transcription factor OsWRKY72 is involved in Cu/Cd toxicity by regulating lignin synthesis in rice

Maintenance of ion homeostasis in plant cells is an essential physiological requirement for sustainable growth,development,and yield of crops.Plants respond to high levels of heavy metals such as copper(Cu)and cadmium(Cd)to avoid irreversible damage at the structural,physiological and molecular levels.Our previous study found that rice germin-like proteins(OsGLPs)are a type of Cu-responsive proteins.The deletion of 10 tandem OsGLP genes on chromosome 8 led to more severe heavy metal toxicity in rice.In this study,we show that rice WRKY transcription factor OsWRKY72 negatively regulates OsGLP8-7transcription.Overexpression of OsWRKY72 weakens the Cu/Cd tolerance of rice when exposed to Cu and Cd.OsWRKY72 suppressed expression of OsGLP8-7 and lignin synthesis genes,resulting in reduced lignin polymerization and consequently lower lignin accumulation in cell walls,thereby increasing the Cu and Cd accumulation.In addition,OsWRKY53 bound to OsWRKY72 to alleviate the transcriptional inhibition of OsGLP8-7.These results revealed that OsWRKY72-OsGLP8-7 is an important module response of rice to heavy metal stress,and that transcription factor OsWRKY72 acts upstream of OsGLP8-7 to regulate Cu/Cd toxicity.

Cd^(2+)浓度对好氧颗粒污泥EPS各组分形成的影响

为探究重金属Cd^(2+)对好氧颗粒污泥系统运行的影响,采用紫外分析法和三维荧光光谱分析法研究了SBR反应器中不同浓度的重金属Cd^(2+)对好氧颗粒污泥EPS总量以及各组分(LB-EPS、SB-EPS、TB-EPS)的产生与组成成分的影响。试验结果表明:低浓度Cd^(2+)(小于0.1mg/L)促进EPS的产生,高浓度Cd^(2+)(大于3mg/L)抑制EPS的产生;SB-EPS随着Cd^(2+)浓度的增加逐渐减少,其中蛋白质含量增加,多糖、腐殖酸明显减少;当Cd^(2+)浓度小于0.1mg/L时TB-EPS显著增加,其中主要增加的成分是蛋白质;当Cd^(2+)浓度大于3mg/L时,TB-EPS的分泌受到抑制,但蛋白质含量仍高于空白对照组,多糖、腐殖酸含量显著降低;LB-EPS受到的影响因素较多,其含量变化不规律。采用扩展DLVO理论剖析了EPS各组分含量的变化对好氧颗粒污泥沉降性能的影响,以期为好氧颗粒化技术在工业废水处理中的应用提供有力的支持。

龙葵与3种外来入侵植物对Cd的富集和生理响应差异比较

为研究本土Cd超富集植物龙葵(Solanum nigrum L.)和3种外来入侵植物鬼针草(Bidenspilosa L.)、紫茎泽兰(Ageratina adenophora Spreng)和紫茉莉(Mirabilisjalapa L.)对Cd污染土壤修复效果和生理响应的差异,采用室内盆栽试验,通过设置0、2、10、30 mg·kg^(-1)不同Cd含量,探究本地种龙葵与3种入侵植物在不同Cd含量处理下对Cd富集、Cd提取效率、叶片光合色素含量、抗氧化酶活性、丙二醛和可溶性糖含量的变化。结果表明:在Cd处理下,鬼针草的地上部生物量均显著高于龙葵和其余2种入侵植物。所有Cd含量处理,鬼针草Cd提取效率均最高(0.61%~1.87%),紫茉莉最低(0.02%~0.03%),龙葵(0.30%~0.79%)和紫茎泽兰(0.24%~1.06%)居中。3种Cd含量处理下,鬼针草叶片叶绿素a、叶绿素b和类胡萝卜素含量在4种植物中最高,鬼针草叶片的抗氧化酶活性均显著高于龙葵,龙葵丙二醛含量显著高于入侵植物。逐步回归分析结果表明,龙葵Cd提取效率与叶片丙二醛含量呈显著负相关、与CAT活性呈显著正相关,鬼针草和紫茎泽兰Cd提取效率均与叶片丙二醛含量呈显著负相关。综上,对于含Cd 2~30 mg·kg^(-1)的土壤进行植物修复时,入侵植物鬼针草比本地植物龙葵更具优势。

虾青素对镉离子(Cd^(2+))诱导下斑马鱼胚胎抗氧化指标的影响

(28.0±0.5)℃下,将100个产后1 h的斑马鱼(Danio rerio)胚胎放在120 mm培养皿中,暴露在<0.02%浓度的二甲基亚砜(DMSO,对照组)、50μg/L Cd^(2+)(低浓度暴露组)、500μg/L Cd^(2+)(高浓度暴露组)和Cd^(2+)+雨生红球藻(Haematococcus pluvialis)虾青素AST联合暴露组(50μg/L Cd^(2+)+100μg/L AST组和500μg/L Cd^(2+)+100μg/L AST组)5个处理组中,120 h后测定斑马鱼幼鱼活性氧(ROS)、丙二醛(MDA)和谷胱甘肽酶(GSH)含量、超氧化物歧化酶(SOD)活性和总抗氧化能力(T-AOC),研究重金属镉离子(Cd^(2+))暴露下斑马鱼胚胎的抗氧化响应,探讨AST对斑马鱼机体氧化损伤的缓解效果。结果表明,斑马鱼胚胎Cd^(2+)暴露120 h后,体内活性氧(ROS)和丙二醛(MDA)含量随着Cd^(2+)浓度的升高而增加;GSH含量、SOD和T-AOC的活性随着Cd^(2+)浓度的增加而降低。说明Cd^(2+)可诱导斑马鱼机体出现氧化应激和氧化损伤。添加AST后,斑马鱼幼鱼体内ROS和MDA含量下降,GSH含量、SOD和T-AOC活性上升,说明添加AST可在一定程度上缓解重金属Cd^(2+)对斑马鱼体内抗氧化指标的负面影响。本研究结果可为AST作为新型鱼类饲料添加剂提供理论依据。

Effects of Different Kinds of Exogenous Auxin on the Growth of Rice Roots under Cadmium Stress

[Objective] The aim was to study the effect of different kinds of exogenous auxin on the growth of rice roots under cadmium stress.[Method] Oryza sativa L.cv Zhonghua No.11 was used as experimental materials to detect the effect of different kinds of exogenous auxin on the growth of rice roots.[Result] The results showed that 0.1 mmol/L Cd treatment could not only increase primary,adventitious and lateral root length but also lateral root number,whereas the shoot growth was inhibited.When supplemented with different concentrations of NAA,IAA,IBA and 2,4-D,the growth of root system varied and similar change trend had been found.At the auxin concentration of 10^-9-10^-7 mol/L in particular 10^-8 mol/L,all four kinds of auxin promoted the elongation growth of primary and adventitious roots,but inhibition was observed when auxin was higher than 10^-7 mol/L.The decreased shoot growth caused by Cd could not be counteracted by supplementing with the four kinds of auxin.However,at the auxin concentration of 10^-9-10^-8 mol/L,NAA could improve rice growth under Cd stress condition.The formation and development of lateral roots on primary and adventitious roots was not only similar but also different after applying the same concentration of four auxins.[Conclusion] The addition of suitable amount of auxin under cadmium stress （such as 10^-9-10^-8 mol/L of NAA and so on） could ease the damage of cadmium on plants to a certain extent.

Effects of Catalase and Ascorbate Peroxidase on the Root Growth of Rice under Cadmium Stress

[Objective] The research aimed to study the correlations between catalase（CAT） and ascorbate peroxidase（ASP） and the growth and development of rice roots under cadmium stress.[Method] Taking rice variety Zhonghua No.11 as materials,the changes of rice seedlings under the treatment conditions of Cd,Cd＋CAT inhibitor,Cd＋APX inhibitor were studied.[Result] Under Cd stress,inhibition of CAT activity caused the significant inhibition on the growth of aerial parts,decreased the number of adventitious roots and lateral roots,but it can significant promote the elongation growth of adventitious roots and lateral roots.Moreover,the length of the first lateral root from root tip on the primary roots and adventitious roots was also increased than control.When APX activity was inhibited,the growth changes of rice were similar with that treated by CAT inhibitor.[Conclusion] CAT and APX may play important roles in the regulation of rice root system growth in both non-stress and Cd-stressed rice

Regulation of ABA on Rice Root System Growth under Cadmium Stress

[Objective] The regulation of ABA on rice root system growth under Cd stress was studied.[Method] Taking rice Zhonghua No.11 as material,changes in rice root system growth were studied under the treatments of Cd,Cd ＋ ABA and Cd ＋ ABA inhibitor.[Result] Exogenous ABA could shorten the length of primary roots and adventitious roots of rice and could obviously inhibit the formation of lateral roots in primary roots and adventitious roots;ABA could obviously shorten the distance from root hair to root tip,but had little effect on the quantity of adventitious roots.[Conclusion] ABA takes part in the regulation in rice root system growth under Cd stress.

Effects of Cadmium Stress on Key Enzymes Involved in Nitrogen Metabolism and Nitrogen,Phosphorus, Potassium Accumulation of Different Varieties of Rice

In this study, the pot experiment was used to explore the differences of activity of key enzymes involved in N metabolism and NPK accumulation under Cd stress during the til iering stage of differen varieties of rice. The results showed that：Cd stress could increase the NPK concentration of different rice type in the til ering stage, while Shen-Liangyou 5867,Yongyou 5550 and Wu-Yunjing 27 showed the highest amplification respectively. Morever, Cd stress can also contribute to the ac-tivity of NR,GS,GOGAT increasing.A s for NR,the Cd stress significantly contribute to NR activity increasing of Huang-Huazhan and Yongyou 538 but is not significant for Wu-Yunjing 27, Shen-Liangyou 5867 and Yongyou 5550, however, the difference among them is not obvious.However, for the activity of GS , Cd stress promote the GS activity. Huang-Huazhan and Wu-Yunjing 27 with low activity in Cd normal level are the most sensitive. Meanwhile the difference between two treatment is the most significant. To the contrary, restrain the GS activity of Shen-Liangyou 5867, Yongy-ou 5550 and the difference is not significant. And under Cd stress, either difference reached significant in GS activity. Cd stress also improve the activity of GOGAT, Wu-Yunjing 27 showed the highest inprovement which showed the lowest GOGAT activity under Cd normal level. Cd stress on rice growth and development of ad-verse, make its lower seed setting rate, 1 000 grain weight decreased, resulting in different degrees of reduction of output of rice.

Physiological Responses of Paspalum vaginatum Sw. to Cd Stress and Its Cd Accumulation Characteristics

The physiological responses of Paspalum vaginatum Sw. to Cd stress and its Cd accumulation characteristics were studied by investigating the effects of different concentrations of Cd on the growth, root vigor, leaf membrane permeability, membrane lipid peroxidation, protective enzyme activity and Cd accumulation of P. vaginatum. When the Cd concentration was over 50.00 mg/kg, with the increased Cd concentration, the CAT activity declined significantly, the synergistic effect between SOD and CAT was weakened, the MDA content increased greatly, and the root vigor decreased, leading to inhibited growth of P. vaginatum. When the Cd concentration was in the range of 0-50 mg/kg, the root vigor of P. vaginatum did not decline obviously, the activity of protective enzymes （SOD and CAT） was enhanced, and the MDA accumulation and cell membrane permeability did not increase significantly, thus the damage of Cd to P. vaginatum was lighter. Roots of P. vaginatum showed strong enrichment capacity for Cd. When the Cd concentration was up to 200.00 mg/kg, the Cd contents in shoot and root of P. vaginatum reached 39.15 and 1 097.38 mg/kg, respectively. It suggests that in the concentration range of 0-50.00 mg/kg, P. vaginatum can make effective responses to Cd stress and grow normally, and it can be planted as a candidate material to remediate Cd-contaminated soil.