Effects of Cu stress on physiological,biochemical,and spectral properties of wheat at different growth stages

To study the mechanism of Cu toxicity on wheat,the characteristics of Cu stress in pivotal growth periods of wheat were explored by field planting methods.The results showed that at the tillering stage,the concentrations of Cu in the leaf cell fluid were significantly higher than those in the cell wall,and the Cu was primarily enriched in cell fluid.At the jointing and heading stages,the Cu concentration in the leaf cell wall was significantly higher than that in the cell fluid,and the main enrichment was transferred to the cell wall.During the above three growth stages,no Cu was discovered in leaf organelles.Further studies showed that the total soluble protein content in wheat leaves at the tillering and jointing stages showed a trend of first rising and then falling with increased Cu dosage.At the heading stage,under low and medium Cu stress,the total soluble protein content showed no remarkable change.Malondialdehyde(MDA)content at the tillering stage increased with the increase of Cu concentration in the soil,while MDA content did not change noticeably at the jointing and heading stages.At the tillering and heading stages,the low concentrations of Cu increased peroxidase(POD)activity.The POD activity decreased gradually with the increased Cu concentration.However,at the high concentrations of Cu,there was no significant difference in the activity of POD.At the jointing stage,the POD activity did not change significantly under the low Cu stress while it was evidently inhibited under high Cu stress.Based on the above studies,further analyses on the correlation between canopy spectral characteristics and the Cu accumulation at different growth stages of leaf cells were performed,and a new combined index SIPI/NDVI705 performed well in Cu content prediction.The results showed that at different growth stages,different sensitive spectral characteristic parameters should be used to predict the Cu content in leaf cells.

Co-exposure of sulfur nanoparticles and Cu alleviate Cu stress and toxicity to oilseed rape Brassica napus L.

Experimentswere performed to explore the impact of sulfur nanoparticles(SNPs)on growth,Cu accumulation,and physiological and biochemical responses of oilseed rape(Brassica napus L.)inoculated with 5 mg/L Cu-amended MS medium supplemented with or without 300 mg/L SNPs exposure.Cu exerted severe phytotoxicity and inhibited plant growth.SNPs application enhanced the shoot height,root length,and dry weight of shoot and root by 34.6%,282%,41.7%and 37.1%,respectively,over Cu treatment alone,while the shoot and root Cu contents and Cu-induced lipid perodixation as the malondialdehyde(MDA)levels in shoots and roots were decreased by 37.6%,35%,28.4%and 26.8%.Further,the increases in superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),ascorbate peroxidase(APX),glutathione reductase(GR)and glutathione S-transferase(GST)enzyme activities caused by Cu stress were mitigated in shoots(10.9%–37.1%)and roots(14.6%–35.3%)with SNPs addition.SNPs also positively counteracted the negative effects on shoot K,Ca,P,Mg,Mn,Zn and Fe contents and root K,Ca,Mg and Mn contents from Cu exposure alone,and significantly promoted the nutrients accumulation in plant.Additionally,in comparison with common bulk sulfur particles(BSPs)and sulfate,SNPs showed more positive effects on promoting growth in shoots(6.7%and 19.5%)and roots(10.9%and 15.1%),as well as lowering the shoot Cu content(40.1%and 43.3%)under Cu stress.Thus,SNPs application has potential to be a green and sustainable technology for increasing plant productivity and reducing accumulation of toxic metals in heavy metal polluted soils.

Effects of Grafting on Root Exudates of Cucumber and Rhizosphere Environment under Copper Stress

[Objective] This study to aimed to investigate the effects of Cu stress on root exudates and microbial activities in rhizosphere of grafted and ungrafted cucum-ber seedlings, and therefore to elucidate the microbial mechanism of grafting for in-creasing cucumber plants tolerance to Cu stress [Method] Four treatments： （1） un-grafted seedlings ＋ test soil （U0）; （2） ungrafted seedlings ＋ test soil ＋ CuSO4·5H2O （U1）; （3） grafted seedlings ＋ test soil （G0）; （4） grafted seedlings ＋ test soil ＋ Cu-SO4·5H2O （G1） were set in the pot culture experiment. The contents of free amino acids, organic acids, phenolic acid and sugars, microbial population and enzyme ac-tivity in the four treatment were measured, respectively. [Result] The secretion of amino acids and organic acids were increased under Cu stress. The amino acids secretions of grafted seedlings roots were obviously higher than ungrafted seedlings except for Phe and Val. At the same time, the secretion of oxalic acid, malic acid, acetic acid, citric acid, cinnamic acid, ρ-hydroxybenzoic acid and benzoic acid of grafted seedlings were significantly higher than ungrafted seedlings as wel . There-fore, more Cu2＋ were restricted in soil by chelating, complexing and precipitation with root exudates, and its toxicity was decreased. The soil microbial biomass C and N in grafted cucumber rhizosphere were significantly higher than those in ungrafted cu-cumber rhizosphere, whereas basal respiration and metabolic quotient were signifi-cantly lower. Under Cu stress, the numbers of actinomyces and nitrogen fixing bac-teria decreased and the number of fungi increased significantly, whereas there was no significant difference in amounts of bacteria. The numbers of bacteria, actino-myces, and nitrogen fixing bacteria in grafted cucumber rhizosphere were significant-ly higher than those in ungrafted cucumber rhizosphere, but the number of fungi was opposite. The activities of soil urease, phosphatase, sucrase and catalase in grafted cucumber rhizosphere were significantly higher than those in ungrafted cu-cumber rhizosphere. [Conclusion] These indicated that the soil microbial environment and soil enzymes activities were improved by grafting under Cu stress, and as a re-sult, the adaptability of cucumber to Cu stress was improved.

Transcriptional profiles in zebrafish atp7a mutants and responses of atp7a mutants to Cu stress

As a copper(Cu)transport ATPase,ATP7A plays an important role in maintaining Cu homeostasis in the body,but the developmental and physiological roles of atp7a in zebrafish embryogenesis are rarely studied.In this study,normal morphological phenotypes of atp7a^(−/−)homozygous zebrafish were observed at both embryonic and adult stages,however,atp7a^(−/−)larvae exhibited delayed touch response and obvious transcriptome changes.Compared with the WT(wild type),differentially expressed genes(DEGs)in atp7a^(−/−)larvae showed the enrichment in gene ontology(GO)terms related to several processes including ATPase activity,oxidoreductase activity,active transmembrane transporter activity,ion binding,and the citrate cycle.Furthermore,decreases in both ATP content and Na+/K+-ATPase activity in atp7a^(−/−)embryos and larvae were unveiled.57 overlapping DEGs were found both in WT stressed with Cu and in WT mutated with atp7a,and GO term analysis indicated the enrichment in the genes related to neurexin family protein binding and neuronal cell-cell adhesion.Moreover,42 overlapping DEGs in Cu stressed WT and Cu stressed atp7a^(−/−)were identified.GO term analysis showed an enrichment in the genes related to heme binding,implying that Cu was independent of the integral function of atp7a to affect heme binding.In addition,genes involved in the negative regulation of angiogenesis were down-regulated in atp7a^(−/−)mutants with and without Cu stress,which failed to occur in WT,implying that the integral function of atp7a is required for maintaining the normal expression of angiogenesis genes.The integrative data in this study demonstrated that atp7a is required for ion transport and angiogenesis,and for Cu-induced neurexin family protein binding defects,rather than for Cu-induced heme binding defects,during zebrafish embryogenesis.These findings provide possible clues for human diseases with ATP7A dysfunction and imbalanced Cu homeostasis.

Study of the tolerance of Hippochaete ramosissimum to Cu stress

We investigated the tolerance of Hippochaete ramosissimum and the changes in physiological metabolism following exposure to copper using pot experiments and analyzing plant physiology and biochemistry. The results showed that Cu tolerance in Hippochaete ramosissimum varied significantly between different populations; the tolerance of plants living in Cu polluted areas for extended periods of time exceeded that of plants living in unpolluted areas.SOD and POD activities in highly Cu tolerant plants increased noticeably following exposure to Cu. This indicates that maintaining and increasing the two kinds of protective enzyme activities are the primary foundations of plant tolerance. However, no change in CAT activity was demonstrated following Cu exposure. In summary, there existed considerable differences in physiological metabolism between different populations of Hippochaete ramosissimum following exposure to Cu.

High Temperature Flow Stress Prediction of Nano-Al_2O_3/Cu Composite Using an Artificial Neural Network

Alumina dispersion strengthened copper composite （nano-Al2O3/Cu composite） was recently emerged as a kind of potentially viable and attractive engineering material for applications requiring high strength, high thermal and electrical conductivities and resistance to softening at elevated temperatures. The nano-Al2O3/Cu composite was produced by internal oxidation. The microstructures of the composite were analyzed by the TEM and its hot deformation behavior was investigated by means of continuous compression tests performed on a Gleeble 1500 thermo-simulator. Making use of the modified algorithm-Levenberg-Marquardt （L-M） algorithm BP neural network, a model for predicting the flow stresses during hot deformation was set up on the base of the experimental data. Results show that the microstructures of the composite are characterized by uniform distribution of nano-Al2O3 particles in Cu-matrix. The sliding of dislocations is the main deformation mechanism. The dynamic recovery is the main softening mode with the flow stress decreasing gently from 500℃ to 850 ~C. The recrystallization of Cu-matrix can be retarded late into as high as 850 ℃, when it happens only partially. The well-trained BP neural network model can accurately describe the influence of the temperature, strain rate, and true strain on the flow stresses, therefore, it can precisely predict the flow stresses of the composite under given deforming conditions and provide a new way to optimize hot deforming process parameters.

Microstructure and properties of Al-Cu-Mg-Ag alloy exposed at 200℃ with and without stress

The effect of stress on the microstructure and properties of an Al-Cu-Mg-Ag alloy under-aged at 165 ℃ for 2 h during thermal exposure at 200 ℃ was investigated. The tensile experimental results show that the remained tensile strength of both specimens at room temperature after being exposed at 200 ℃ with and without applying stress rises firstly, and then drops with the increasing of exposure time. The peak value of the remained strength reaches 439 MPa for non-stress-exposure for 10 h, and 454 MPa after being exposed with stress loaded for 20 h at 220 MPa. The elongation change is similar to that of strength. After being exposed for 100 h, specimen exposed at 220 MPa still remains a tensile strength of 401 MPa, larger than that exposed without applying stress. TEM shows that the microstructure of under-aged alloy is dominated by - phase mainly and a little θ′ phase. The θ′ and - phases are believed competitive with increasing exposure time. The width of precipitation free zone(PFZ) increases and the granular second phase precipitates at grain-boundary correspondingly. It is shown that the mechanical properties of alloy decrease slightly and present good thermal stability after thermal exposure at 200 ℃ and 220 MPa for 100 h.

Flow Stress Behavior and Processing Map of Al-Cu-Mg-Ag Alloy during Hot Compression

The hot deformation behavior of Al-Cu-Mg-Ag was studied by isothermal hot compression tests in the temperature range of 573-773 K and strain rate range of 0.001-1 s^-1 on a Gleeble 1500 D thermal mechanical simulator. The results show the flow stress of Al-Cu-Mg-Ag alloy increases with strain rate and decreases after a peak value, indicating dynamic recovery and recrystallization. A hyperbolic sine relationship is found to correlate well the flow stress with the strain rate and temperature, the flow stress equation is estimated to illustrate the relation of strain rate and stress and temperature during high temperature deformation process. The processing maps exhibit two domains as optimum fields for hot deformation at different strains, including the high strain rate domain in 623-773 K and the low strain rate domain in 573-673 K.

The Effects of Nonuniform Thermal Boundary Condition on Thermal Stress Calculation of Water-Cooled W/Cu Divertors

The thermal boundary condition has very important effects on the accuracy of thermal stress calculation of a water-cooled W/Cu divertor. In this paper, phase-change heat transfer was simulated based on the Euler homogeneous phase model, and local differences of liquid physical properties were considered under one-sided high heating conditions. The steady-state temperature field and thermal stress field under nonuniform thermal boundary conditions were obtained through numerical calculation. By comparison with the case of traditional uniform thermal boundary conditions, the results show that the distribution of thermal stress under nonuniform thermal boundary conditions exhibits tbe same trend as that under uniform thermal boundary conditions, but is larger in value. The maximum difference of maximum von Mises stress is up to 42% under the highest heating conditions. These results provide a valuable reference for the thermal stress caleulat.ion of water-cooled W/Cu divertors.

Cu-2Ti-0.3Zr合金的热变形行为及组织演变

通过真空熔炼技术制备了Cu-2Ti-0.3Zr合金,在变形温度为750~900℃及应变速率为0.001~1 s^(-1)的条件下,采用Gleeble-1500D热模拟试验机对Cu-2Ti-0.3Zr合金进行了热变形试验。通过分析合金的热变形行为,构建了其本构方程和热加工图,并分析了其在不同变形条件下的微观组织演变。结果表明:合金的流变应力随变形温度的降低而增加,随应变速率增加而上升。通过绘制热加工图,得到了Cu-2Ti-0.3Zr合金的最佳热加工工艺:变形温度为825~900℃和应变速率为0.010~0.050 s^(-1)。在较优的工艺条件下,合金的组织主要由变形晶粒和等轴亚晶组织组成。

Cu箔缓冲层对SiO_(2)/TC4接头组织性能的影响

针对SiO_(2)石英玻璃/TC4钛合金钎焊接头易脆裂难题,以Cu箔为缓冲层,采用AgCuTi活性钎料对石英玻璃/TC4钛合金进行真空钎焊。通过金相显微镜、扫描电镜、能谱仪以及X射线衍射仪、力学试验机分析Cu缓冲层及不同钎焊工艺对SiO_(2)/TC4接头组织结构及力学性能的影响。研究结果表明,在合适的钎焊温度下,Cu箔缓冲层的加入一方面在SiO_(2)/AgCuTi界面处形成了合适厚度的TiSi_(2)+Ti_(4)O_(7)/Cu_(2)Ti_(4)O双层结构,另一方面在焊缝中形成大量韧性较好的Cu固溶体,这些固溶体在钎焊冷却过程中通过钎缝自身的蠕变和屈服吸收接头中的残余应力,减少接头残余应力,提高了钎焊接头的力学性能。当钎焊温度为900℃、保温时间10 min时,SiO_(2)/TC4钎焊接头抗剪强度最高,达到38 MPa。Cu箔缓冲层的加入显著改善了SiO_(2)石英玻璃/TC4钎焊接头的力学性能。

Methods for obtaining two way memory effect and stressed two way memory effect of CuAlNi single crystals

Various training methods for two way memory effect (TWME) and stressed two way memory effect (STWME) were tried on Cu 13.4Al 4.0Ni (mass fraction, %) single crystals by applying tensile stress along 〈001〉 direction of β phase. The training method of cooling with load can induce a lot of martensite prone to stabilize, thus cause large residual deformation, wide hysteresis and small TWME. Training with constant load can produce STWME larger than 8% with the least residual deformation. By training procedure of martensite reorientation below M f followed by thermal cycling, the TWME is relatively large with very small residual deformation and with comparatively narrow hysteresis of two way memory. The obtained two way memory curve after such training is not a closed loop, and the obtained TWME is not stable. However, these can be improved by thermal cycling. Training with martensite reorientation below M f and thermal cycling under relatively low constant stress throughout the whole training procedure is the optimum way of obtaining TWME, and more than 1.7% TWME can be obtained. The thermomechanical history of the sample has a pronounced effect on the training result. Thermomechanical cycling has a softening effect on martensite. [

FINITE ELEMENT ANALYSIS ABOUT STRESS AND STRAIN OF SURFACE PEELING IN Cu-Fe-P SHEET

The microstructure of surface peeling in finish rolled Cu-0.1Fe-0.03P sheetis analyzed by scanning electron microscope and energy dispersive spectroscope. Fe-rich areas ofdifferent contents are observed in the matrix. The stress distributions and strain characteristicsat the interface between Cu matrix and Fe particle are studied by elastic-plastic finite elementplane strain model. Larger Fe particles and higher deforming extent of finish rolling are attributedto the intense stress gradient and significant non-homogeneity equivalent strain at the interfaceand accelerate surface peeling of Cu-0.1Fe-0.03P lead frame sheet.

Effect of tensile stress on microstructure evolution of Al-Cu-Mg-Ag alloys

The effect of tensile stress on thermal microstructure evolution of Ω phase in an Al-Cu-Mg-Ag alloy with high Cu/Mg ratio and higher Ag content was investigated by transmission electron microcopy(TEM) .The samples were aged at 200 ℃ for 1 h(T6 condition),then thermal exposed at 250 ℃ for 100 h with and without a tensile stress(130 MPa),respectively. The results indicate that Ω precipitates uniformly disperse in the matrix as a major precipitate after artificially aging at 200 ℃ for 1 h(T6 condition). Exposed at 250 ℃ for 100 h without stress,Ω precipitates dissolve dramatically. Whereas,during stress exposure they coarsen unexpectedly rather than dissolve into matrix. It can be deduced that the stress retards the redissolution of Ω phase.

“Giant pressure shadow” structure and ore-finding method of tectonic stress field in the Tongchang Cu-Au polymetallic orefield,Shaanxi,China:Ⅱ.Dynamics of tectonic ore-forming processes and prognosis of concealed ores

The Tongchang orefield is located in the central part of the Mianxian-Lueyang-Yangpingguan area that is celebrated as a 'gold triangle' area,at the juncture of the latitudinal tectonic zone of South Qinling,the Longmenshan Cathysian tectonic zone and the Sichuan-Yunnan longitudinal tectonic zone,where there are distributed Cu-Au polymetallic ore deposits(occurrences) including the Tongchang,Chenjiaba,Qinjiabian,Hongtushi,Yinshangou and Xiakouyi ore deposits(mineralization).Based on the "giant pressure shadow" structure put forward and demonstrated by numerical modeling of the tectonic stress field and the static photoelasticity experiments on the basis of tectonic ore-controlling laws in the orefield,tectonic metallogenesis driven by orefield tectonic stress has been discussed in terms of its geological setting,orefield geomechanics,and tectonic stress field.It is thought that the dynamic evolution model of the tectonic stress field controls the whole process of formation of the polymetallic ore deposits(mineralization) in the orefield,as well as the deformation field.As a result,it controls the emplacement of rockbodies and the transformation of ore-source bodies,and provides both the channel-ways for ore-forming fluids and ore-hosting space.Furthermore,it controls the migration potential field of fluids and,thereafter,its flow direction,rate and volume;the tectonic stress field also controls the energy field and hence controls the position of occurrence of ore deposits and their scale.The method of tectonic stress field has been applied to ore prognosis in the orefield.The rules of magmatic emplacement and metallogenic fluid migrating and concentrating under the control of the structural stress field were expounded,hence providing the theoretical basis for the prognosis of concealed ores.In addition,a number of important target areas have been defined.

AlN/Cu钎焊接头残余应力的数值模拟研究

氮化铝(AlN)陶瓷可用于高压大功率绝缘栅双极型功率管(IGBT)的封装,并以表面覆铜(Cu)的方式实现散热功能。但AlN和Cu存在巨大的物性差异,易在连接中残留较大的残余应力。针对AlN/Cu钎焊接头的残余应力进行有限元数值模拟研究,探究压力载荷、冷却速度以及钎料厚度对接头残余应力的影响规律。结果表明,在所研究的范围内,AlN/Cu钎焊接头中最大轴向应力均出现在AlN陶瓷棱边靠近钎料金属层处,最大剪切应力则出现在靠近外侧边的AlN陶瓷与钎料金属层界面处。压力载荷降低、冷却速度加快和钎料层厚度增加均会增大最大轴向应力和剪切应力,但应力分布较为一致。本研究可为大功率IGBT覆Cu AlN陶瓷基板的高可靠性封装提供理论指导。

Cu-Zr-Cr合金热变形行为及微观组织研究

目的探究应变速率、变形温度及Cr含量对Cu-Zr-Cr合金组织与性能的影响。方法采用真空熔炼法制备了Cu-0.3Zr-0.05Cr和Cu-0.3Zr-0.15Cr合金。热锻后,使用Gleeble-1500型热模拟试验机分别对2种合金在温度为750~900℃、反应速率为0.003~1 s^(−1)的条件下进行热压缩实验。绘制了2种合金在不同热变形条件下的真应力-真应变曲线,建立了本构方程,绘制了Cu-0.3Zr-0.15Cr合金的热加工图,观察并分析了合金的微观组织。对温度850℃、应变速率1 s^(−1)条件下热压缩Cu-0.3Zr-0.15Cr合金进行了TEM观察。结果流变应力随变形温度的升高而降低,随应变速率的增大而增大。Cu-0.3Zr-0.05Cr和Cu-0.3Zr-0.15Cr合金的热激活能分别为488.9 kJ/mol和491.3 kJ/mol,确定了Cu-0.3Zr-0.15Cr合金的最佳加工区域。当Cu-0.3Zr-0.05Cr和Cu-0.3Zr-0.15Cr合金在850℃、应变速率1 s^(−1)下进行热压缩实验时,垂直于压缩方向的晶粒尺寸分别为25μm和21.4μm。Cu-0.3Zr-0.15Cr合金中存在2种析出相,分别为细小Cr析出相和粗大未溶解的Cu5Zr相,尺寸分别约为10 nm和840 nm。结论Cu-Zr-Cr合金在850℃、应变速率为1 s^(−1)的条件下进行热变形时具有较好的晶粒细化效果,Cr元素的增加会细化晶粒并且提高合金的热激活能,改善合金的热加工性能。

Al-Zn-Mg-Cu-Zr合金的热变形行为研究

以7000系Al-Zn-Mg-Cu-Zr合金为研究材料,在Gleeble1500热模拟试验机上进行变形温度250~400℃,应变速率0.01~10 s^(-1)条件下的等温压缩试验。研究结果表明:合金在等温压缩过程中的流变应力随着应变速率的增大而增大,随着变形温度的增大而减小。当应变速率为10 s^(-1),变形温度为250℃时,合金的峰值应力可达205 MPa。大部分的真应力-应变曲线呈现动态再结晶特征,结合TEM分析,动态再结晶的形成机制是位错通过滑移和攀移逐渐演变成小角度晶界(2°~15°)和大角度晶界(>15°),依靠位错重排在原始晶粒内部形成亚结构,最终形成完整晶界。同时,采用Arrhenius模型和Zener-Hollomon参数方程,构建了Al-Zn-MgCu-Zr合金的本构方程,其中合金的平均变形激活能为324 187 J/mol。此外,通过Prasad失稳判据等模型,构建了0.2、0.4以及0.6应变下的Al-Zn-Mg-Cu-Zr合金的热加工图,获得可加工窗口为:252~400℃,0.01~0.015 s^(-1)。

水花生抗氧化系统在抵御Cu^(2+) 胁迫中的作用

在Hoagland培养基中加入CuSO4 以模拟水体Cu2 +污染环境 ,从不同Cu2 +浓度和中毒时间两个角度 ,研究了水花生 (Alternantheraphiloxeroides (Mart.)Griseb .)的酶与非酶抗氧化系统在抵御Cu2 +胁迫中的作用。实验结果显示 ,轻—中度污染的Cu2 +(小于 70mg/L)即能刺激水花生超氧阴离子 (O-·2 )的积累 ,并导致脂质过氧化和膜透性的改变。在Cu2 +胁迫过程中超氧化物歧化酶 (SOD)、过氧化物酶 (POD)能发生大幅度应激性提高 ,并在实验范围内的较高浓度和中毒中后期起主要抗氧化作用 ,过氧化氢酶 (CAT)在此过程中作用不明显 ,谷胱甘肽过氧化物酶 (GSH_Px)在较低浓度和中毒早期能被小幅度激活并起作用 ,抗坏血酸 (AsA)通过还原型向氧化型的转变 。

外源水杨酸对Cu胁迫下水培烟草生长及营养元素吸收利用的影响

以耐Cu性较强的烟草品种W38(Nicotiana tabacum cv.W38)和耐Cu性较弱的本氏烟(Nicotiana benthamiana)为试验材料,设置水培处理组即CK(Cu2+0 mg L–1,SA 0μmol L–1,即对照组)、T1(Cu2+4 mg L–1,SA 0μmol L–1)、T2(Cu2+4 mg L–1,SA 100μmol L–1)、T3(Cu2+4 mg L–1,SA 300μmol L–1)、T4(Cu2+4 mg L–1,SA 500μmol L–1),探讨SA对烟草生长特性及根、茎、叶不同器官中元素吸收规律的影响。结果表明,经过4 mg L–1 Cu胁迫15 d后,2个品种的烟草生长均受到一定程度的抑制,不同器官中Cu含量均显著升高,K、Ca、Mg、Fe、Zn、B、Mn的吸收受到抑制,而在营养液中添加适宜浓度的SA能够有效缓解Cu胁迫对2个品种烟草根长、株高、鲜重的抑制作用,并降低烟草体内Cu含量。与T1处理组相比,本氏烟的根、茎、叶中Cu含量最大分别下降25.05%、39.78%和22.91%,W38的根、茎、叶中的Cu含量最大分别下降23.27%、37.30%和28.88%,并促进了营养元素K、Ca、Mg、Fe、Mn的吸收,但是对Zn、B元素的吸收影响并不明显。由此可知,高浓度的Cu胁迫会抑制烟草的生长及营养元素的吸收和运输,施加适宜浓度的外源水杨酸有利于营养元素的吸收和促进烟草的生长发育,在本试验浓度范围内施加300μmol L–1的水杨酸可显著缓解Cu胁迫对烟草的抑制作用。