外源一氧化氮对NaCl胁迫下番茄幼苗光合作用和离子含量的影响

在100.mmol/L.NaCl胁迫下,研究了外源一氧化氮供体硝普钠(SNP)处理对番茄幼苗光合作用和离子含量的影响。结果表明,外源一氧化氮能使在NaCl胁迫下的番茄幼苗叶片叶绿素含量、净光合速率(Pn)、气孔导度(Gs)、叶绿素荧光参数Fv/Fo和Fv/Fm显著提高,胞间CO2浓度(Ci)明显下降;番茄幼苗根系、叶片中K+、Ca2+和Mg2+含量均显著提高,Na+含量明显降低。表明外源一氧化氮可以减轻盐胁迫对番茄幼苗叶片光合功能的不利影响,缓解NaCl胁迫对番茄幼苗的抑制作用。     

镉胁迫条件下磷肥对结缕草光合特性的影响

采用盆栽试验,研究镉(50 mg·kg-1)胁迫下不同磷肥水平(50、100、150 mg·kg-1)对结缕草生长及光合特性的影响。结果表明,镉胁迫下结缕草的生长和光合特性受到抑制,施加100 mg·kg-1磷肥的结缕草叶长比只受镉胁迫组增加53.33%,根长增加70.5%,叶绿素a+b含量增加42.85%,净光合速率(Pn)增加54.75%,蒸腾速率(Tr)增加94.05%,水分利用效率(WUE)增加45.85%,PSⅡ原初光能转化效率(Fv/Fm)增加12.84%,且与镉胁迫组差异显著。施加150 mg·kg-1磷肥结缕草叶片的胞间二氧化碳浓度(Ci)、表观光电子传递效率(ETR)比镉胁迫组降低。除气孔导度(Gs)在50 mg·kg-1磷肥处理后显著增加,结缕草叶长、根长、叶绿素含量、Pn、Tr、Fv/Fm、Ci和ETR等指标均随磷肥浓度增加呈现先增加后减少的趋势。通过结缕草生长和光合指标可以看出,施用磷肥可以缓解镉对结缕草的胁迫,施加100 mg·kg-1磷肥效果显著。     

高温强光下Ca2+对西葫芦幼苗膜质过氧化、抗氧化酶系统及热耗散的影响

为探明不同浓度外源Ca2+对高温强光胁迫下西葫芦植株幼苗的影响,本试验选用西葫芦(Cucurbitapepo L.)品种"阿兰一代"为试验材料,通过外源喷施不同浓度CaCl2溶液,研究了Ca2+对高温强光胁迫下西葫芦幼苗叶绿素荧光特性、膜质过氧化及抗氧化酶系统的影响。结果表明,较低浓度Ca2+处理(5~20 mmol.L 1)可有效提高高温强光下西葫芦幼苗超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)和过氧化氢酶(CAT)活性,降低丙二醛(MDA)、过氧化氢(H2O2)、超氧阴离子自由基(O2&)含量和膜透性,还原型谷胱甘肽(GSH)含量升高;同时西葫芦叶片PSII的最大光化学效率(Fv/Fm)、PSⅡ实际光化学效率(ΦPSⅡ)和光化学猝灭系数(qP)较高,而非光化学猝灭系数(NPQ)较低。说明5~20 mmol.L 1Ca2+处理对高温强光胁迫具有明显的缓解作用,同时其热耗散较小。当Ca2+处理浓度超过40 mmol.L 1时对高温强光胁迫缓解效应不明显。     

鸡冠花(Celosia cristata Linn)对Cs和Sr的胁迫反应及其积累特征

通过水培试验研究了不同浓度133Cs和88Sr对鸡冠花(Celosia cristata Linn)幼苗株高、根长、叶绿素和丙二醛等的影响及植株对2种元素的积累特征。结果表明,低浓度(0.1和0.5mmol/L)133Cs和88Sr处理下,鸡冠花幼苗的株高和根长与对照无显著差异,但高浓度(1.0和5.0mmol/L)的133Cs和88Sr会抑制其生长;鸡冠花幼苗的叶片、茎段和根部干重随着133Cs和88Sr处理浓度的增加而减少。133Cs和88Sr在鸡冠花幼苗体内的分布均为根部茎段叶片。随核素133Cs和88Sr浓度的上升,鸡冠花幼苗叶绿素含量均呈先升再降趋势,而MDA含量呈先降后升趋势。     

Sr胁迫对油菜幼苗抗氧化指标影响的研究

在石英砂和Hoagland营养液培养条件下,用浓度为0、10、20和40mmol/L的88Sr2+(88SrC l2)处理油菜幼苗(Brassica napus L.)(三叶期到六叶期),动态研究Sr胁迫对油菜幼苗抗氧化指标的影响,以及Sr2+积累量和富集能力的变化。结果表明,油菜幼苗对Sr2+表现出高富集能力,富集能力依次为:叶茎根,Sr2+浓度越高,富集能力越低。与对照相比,Sr2+胁迫下的油菜超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量随Sr2+浓度的增加及胁迫时间的延长呈先上升后下降趋势;过氧化物酶(POD)和过氧化氢酶(CAT)活性则随富集Sr2+能力的提高而降低。因此得出结论,油菜幼苗对Sr胁迫具有较高的耐受能力和富集能力;叶片是最主要的富集器官;富集能力与POD,CAT活性显著负相关。     

外源脱落酸增强甘薯幼苗耐盐性的作用

【目的】本文系统研究了不同浓度NaCl胁迫及外源脱落酸(ABA)对NaCl胁迫下甘薯幼苗生根及一些生理生化特性的影响,探讨了外源ABA对盐胁迫下甘薯幼苗的缓解效应,为增强盐碱地甘薯耐盐性、 提高产量提供理论依据。【方法】以甘薯种植品种徐薯25为实验材料,在装有石英砂的具孔塑料盆中放入培养室自然光照/昼夜温度[(261)/(171)℃]中培养,并进行不同浓度NaCl处理以及对NaCl 300 mmol/L胁迫甘薯幼苗叶片喷施ABA溶液,连续处理7 d后,测定生根数,使用CIRAS-1型便携式光合仪测定光合作用指标、 植物效率分析仪测定叶绿素荧光参数、 采用比色法测定丙二醛、 脯氨酸、 可溶性糖含量和超氧化物歧化酶活性、 用原子吸收分光光度计测定Na+、 K+、 Ca2+含量,利用SPSS13.0和Excel软件对数据进行处理分析。【结果】低浓度 NaCl胁迫(50 mmol/L)对甘薯幼苗影响较小; 随着盐度的增加,甘薯生根不断减少,相对电导率、 丙二醛(MDA)、 脯氨酸和可溶性糖含量持续增加,甘薯叶片超氧化物歧化酶(SOD)活性呈先增加后降低趋势; 叶片净光合速率(Pn)、 蒸腾速率(Tr)、 气孔导度(Gs)、 光系统Ⅱ(PSⅡ)最大光化学效率(Fv/Fm)、 捕获的激子将电子传递到电子传递链中超过QA的其他电子受体的概率(0)、 用于电子传递的量子产额(E0)逐渐降低,放氧复合体活性(Vk)和用于热耗散的量子比率(D0)不断增加; 叶片中Na+含量增加,K+、 Ca2+和K+/Na+水平降低。高浓度(300 mmol/L)NaCl胁迫下,甘薯幼苗的正常生理代谢受到显著抑制。适当增加外源ABA浓度,能够显著缓解NaCl胁迫造成的伤害作用,以ABA浓度为70 mol/L的缓解效果最好。【结论】外源ABA可显著促进盐胁迫下甘薯幼苗生根,维持细胞膜的稳定性,降低膜脂过氧化程度,调节植物细胞的渗透和离子动态平衡,使甘薯幼苗叶片维持较高的Fv/Fm、 0、 E0和较低的Vk、 D0,缓解PSⅡ光抑制的程度,改善植物的光合作用,提高植物的耐盐性。因此,喷施70 mol/L ABA是缓解NaCl胁迫效应,提高甘薯幼苗耐盐性的一种有效方法。     

营养液对鸭儿芹幼苗生长、抗氧化酶活性及叶绿素荧光参数的影响

为了探索适合鸭儿芹幼苗生长的营养液浓度,分别研究了6种山崎营养液浓度（1/12s、1/10s、1/8s、1/4s、1/2s和1s)对鸭儿芹幼苗生长及叶绿素荧光参数的影响。结果表明,在1/8s浓度下,鸭儿芹幼苗的各生长因子（株高、单株叶面积、茎粗、地上部鲜重、干重,地下部鲜重、干重,株鲜重、干重）均达到最大。壮苗指标随着营养液浓度的增大出现先上升后降低的趋势,在1/8s浓度下亦达到最大,且显著高于其它处理(P 0. 05)。在1/12s～1/8s的浓度变化下,随着营养液浓度的增大,POD、CAT以及SOD活性在逐渐上升,MDA含量在逐渐降低,而在1/8s~1s的浓度变化下,随着营养液浓度的增大,POD、CAT以及SOD活性在逐渐降低,MDA含量在逐渐上升,在1/8s浓度下POD、CAT以及SOD活性达到最大,MDA含量达到最小。叶绿素a、叶绿素b及叶绿素总量出现先上升后下降的趋势,在1/8s浓度下均达到最大。1/4s～1s浓度,初始荧光（Fo）值均高于1/12s～1/10s处理,而最大荧光（Fm）、PSⅡ的潜在活性（Fv/Fo）、PSⅡ最大光化学效率（Fv/Fm）值分别低于1/12s～1/10s处理;1/8s浓度的Fo值达到最小,而Fm、Fv/Fo、Fv/Fm值达到最大。实验表明了营养液浓度对鸭儿芹幼苗具有双重作用,即低浓度下随浓度的升高,营养胁迫逐渐减低,促进幼苗生长;高浓度下随浓度的升高,营养胁迫逐渐增强,抑制幼苗生长。结果得出,采用1/8浓度的山崎配方是鸭儿芹幼苗生长的最适营养液浓度。     

钙、硅对铝胁迫下荞麦光合生理的影响

采用营养液培养法,研究了钙、硅对荞麦根长、光合作用和叶绿素荧光的影响。结果表明,15 d时0.5 mmol/L和5 mmol/L Al3 处理降低了荞麦根长、叶绿素含量、净光合速率(Pn)、气孔导度(Ci),对叶绿素荧光Fv/Fm、Fv/Fo的影响不大,30 d后以上伤害均加重。配施钙或硅的处理,能促进根的伸长和提高叶绿素含量,并使叶片的Pn、Ci保持在较高的水平,施硅能明显提高荞麦叶片的叶绿素荧光Fv/Fm、Fv/F,而钙的影响不大。硅对铝胁迫的缓解效果好于钙。     

土壤干旱及复水对侧柏叶绿素荧光参数的影响

为了研究不同程度土壤干旱及旱后复水对侧柏幼苗叶绿素荧光参数的影响,以盆栽1年生侧柏幼苗为试验材料,设置4个水分梯度[土壤相对含水量(RSWC)为:40%,52.16%,70%,87.84%],以充分供水(RSWC为100%)为对照,经干旱胁迫60 d后复水,测定了复水前及复水后2,24,48,72 h叶绿素荧光参数。结果显示:随着土壤干旱胁迫程度的加剧,侧柏幼苗PSⅡ的最大光化学量子产量Fv/Fm、相对光合电子传递速率ETR和实际光化学量子产量Yield总体上呈现下降的趋势,而非光化学淬灭系数NPQ则呈现上升的趋势,其中土壤相对含水量为40%的重度胁迫Fv/Fm,ETR和Yield分别比对照下降1.1%,4.5%,4.9%,而NPQ比对照增加22.6%。复水后叶绿素荧光都得到了恢复,在复水24 h除70%的处理其他处理Fv/Fm达到最大,其中重度胁迫40%的处理比对照上升3.1%。在复水48 h各胁迫处理Yield,ETR达到了最大值,40%的重度胁迫分别比对照上升1.0%,1.2%。由此可知,干旱胁迫尤其是重度胁迫,虽然对侧柏幼苗PSⅡ有一定的破坏,对光合作用有一定程度的影响,但复水后各指标都得到了相应的恢复。     

外源Ca2+对NaCl胁迫下西葫芦生长特征及光合、生理特性的影响

以西葫芦品种阿兰一代为试验材料,研究外源Ca2+对NaCl胁迫下西葫芦植株生长特征及光合、生理特性的影响.结果表明,较低浓度(5 mmol/L)Ca2+处理对NaCl胁迫的缓解作用不明显;当Ca2+浓度增加到10 mmol/L时,显著改善了NaCl胁迫下西葫芦植株的生长状况,使株高增高、叶面积增大,该条件下,西葫芦叶片丙二醛(MDA)和脯氨酸(Pro)含量维持在较低水平,说明植株受到的胁迫较小;10 mmol/LCa2+处理叶片的过氧化氢酶(CAT)和过氧化物酶(POD)活性最高,分别比CK增加20.6％和52.2％,叶绿素a、b含量较高;10～20 mmol/L Ca2+处理的光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)均高于CK和30 mmol/L处理,而胞间CO2浓度(Ci)显著低于CK和30 mmol/L处理;当Ca2+处理浓度超过20 mmol/L时对NaCl胁迫的缓解作用下降;当Ca2+浓度达到30 mmol/L时,各指标与CK间的差异不显著.综合分析认为,10 mmol/L的Ca2+处理浓度对NaCl胁迫的缓解效果最为显著.     

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。     

Infrared spectra of Cu2+ Pb2+ and Ca2+ complexes of soil humic substances

An infrared spectroscopic investigation of the complexes of Cu²⁺, Pb²⁺, and Ca²⁺ with humic and fulvic acids demonstrated the participation of OH and CO groups in addition to COOH in the binding of heavy-metal cations. The degree to which metal-carboxylate linkages are ionic or covalent cannot be accurately determined from the positions of antisymmetric and symmetric carboxylate stretching vibrations due to interference from covalent bonding with other groups. The apparent order of the reaction of three divalent cations with humic and fulvic acids was Cu²⁺ > Pb²⁺ > Ca²⁺.     

Differential Complexation between Zn2+ and Cd2+ with Fulvic Acid: A Computational Chemistry Study

Fulvic (FA) and humic acids (HA) from the solubilization of organic matter are significant agents of the complex of metallic ions in soil and water. Cadmium ions are important natural water pollutants which are discharged along with electroplating and zinc metallurgy liquid wastes, zinc and cadmium being always associated with isomorphic substitution. In this paper we study the complexes formed by Zn²⁺ and Cd²⁺ with fulvic acids, using computational chemistry. We carried out relative free energy calculations using a thermodynamic cycle and Free Energy Pertubation (FEP) and Density Functional Theory (DFT-B3LYP/6-31G**) methods. We also computed the interaction energies between orbitals from Natural Bond Order (NBO) calculations. Cd-FA complexes, octahedral with four water molecules in the coordination sphere are more stable than Zn-FA complexes, tetrahedral with two water molecules. This means that FA should be a better ligand for Cd²⁺ bioavailability and toxicity in natural aquatic environments.     

Loading of VO2+ and Cu2+ to partially oxidized charcoal fines rejected from Brazilian metallurgical industry

Purpose

Charcoal is utilized in Brazil for the metallurgical industry. Small size pieces, called charcoal fines, are rejected and sometimes are used to produce energy by burning. This charcoal can be used as soil conditioner to improve retention of metal ions in soil. However, changing the charcoal's surface chemistry via oxidation may increase retention of metal ions.

Materials and methods

Two kinds of oxidants were employed, nitric acid and selenium dioxide/hydrogen peroxide. Vanadyl ion (VO²⁺) and copper ion (Cu²⁺) were utilized as probe to study the metal ion complexation by the partially oxidized charcoal obtained. FTIR and EPR spectroscopy were used to characterize the materials.

Results and discussion

Oxidation with nitric acid increased nitrogen content, while oxidation with SeO₂/H₂O₂ elevated carbon content of treated charcoals. Organic free radicals (OFRs) with the unpaired electron in p orbitals of aromatic structures were confirmed by the EPR g-factors that ranged from 2.0038 to 2.0031. The oxidation with selenium dioxide/hydrogen peroxide formed charcoal with largest quantity of OFR. Loading charcoal with VO²⁺ and Cu²⁺ resulted in formation of complexes were oxygen acted as coordination atom. The formed complexes were of axial symmetry. The configurations around the Cu²⁺ ions were: CUNCu²⁺ complex (more stable square planar symmetry) and CFNCu²⁺ complex (less stable distorted tetrahedral configuration). Both complexes had oxygen as coordinating atoms. CFNVO²⁺ and CFSeVO²⁺ complexes presented complexation sites of axial symmetry, C_4v, with oxygen as coordinating atoms.

Conclusions

The oxidative treatment of charcoal with SeO₂/H₂O₂ is more appropriate to produce soil organic conditioner for complexation of metal ions.     

电位计滴定法对Co2+, Ni2+, Cu2+ and Zn2+与胡敏酸和富里酸形成复合物时的结合常数的确定

The formation constants of Co^2 ,Ni^2 ,Cu^2 and Zn^2 complexes with humic acid(HA) and fulvic acid(FA) in red soil wrer determined by the potentiometric titration method.The constants as a function of composition of the complexation solutions were obtained by two graphical approaches respetively,The formation constants decreased with increasing concentration of metal in the solution,The results provide unambiguous evidence for the heterogeneity of the function groups of humic substances,the formation constants of FA were much smaller than those of HA,and the formation constants of Cu^2 were much greater than those of Co^2 ,Ni^2 and Zn^2 ,The potentiometric titration methon for determining formation constants are also discussed in the article.     

碳化稻壳吸附严寒地区村镇地下水Fe2+与Mn2+的性能分析

为低温同步净化铁锰地下水,保障严寒村镇饮用水安全,优选600℃碳化稻壳CRH600,基于X射线衍射分析(Xray diffraction,XRD)、扫描电子显微镜(scanning electron microscope,SEM)、比表面积及孔结构分析(Brunauer-Emmett-Teller nitrogen sorption,BET-N2)、傅立叶红外线光谱分析(Fourier transform infrared spectroscopy,FTIR)、Boehm测定法等表征剖析CRH600吸附Fe~(2+)、Mn~(2+)机理,通过单因素试验确定最佳投加量与溶液p H值,采用吸附等温线-动力学-热力学理论揭示CRH600低温吸附性能,考察CRH600低温再生能力。结果表明:CRH600比表面积大,稻壳碳化后表面官能团含量增多,其中-OH凭借离子交换与表面络合作用对Fe~(2+)、Mn~(2+)去除贡献最大。10℃时CRH600对溶液中混合的铁锰不存在竞争吸附;最佳溶液p H值分别为5、6,最佳投加量分别为6、10 g/L。吸附过程符合准二级动力学模型与Langmuir模型,受膜扩散与颗粒内扩散控制,饱和吸附量分别为5.85、2.83 mg/g。吸附自发放热、熵减,低温效果佳,物理与化学作用并存。H2SO4为吸附饱和CRH600的最优解吸剂,最佳吸附-解吸循环次数分别为5、3,再生CRH600对Fe~(2+)、Mn~(2+)的平衡吸附量可达解吸前的80%、90%。研究结果为改性稻壳颗粒低温去除地下水铁锰的应用提供了充分的基础数据与理论支撑。     

Response of potted anthurium (Anthurium andreanum Lind.) to the K+: Ca+2: Mg+2 balance in the nutrient solution

The climatic conditions of the humid tropical areas of México allow the year-round production of cut flowers and potted plants of anthurium. However, the scarce basic and applied research on tropical ornamental species limits the development of technology to increase productivity and quality. In this article, we are reporting the information as to the effect of the proportions of potassium (K⁺), calcium (Ca⁺²), magnesium (Mg⁺²) in the nutrient solution on anthurium growth using mixture analysis and response surface methodology. The sum of all the three cations was 20 meq L^?1 and each one is expressed as a fraction of this total concentration. Response surface analysis detected that spathe and leaf areas decreased in plants fed with solutions of high proportions of Mg⁺². Total shoot and root fresh weight, as well as total dry weight and root volume, also demonstrated the deleterious effects of high Mg⁺². In general, the best growth occurred in two areas of the explored space; a) an area of high Ca⁺², with optimum proportions ranging from 0.24–0.44 for K⁺, 0.54–0.68 for Ca⁺², and 0.01–0.08 for Mg⁺², and b) another area of high K⁺, on which the optimum proportions ranged 0.54–0.65 for K⁺, 0.25–0.29 for Ca⁺², and 0.10–0.21 for Mg⁺². Shoot and root K⁺, Ca⁺², and Mg⁺² concentration was significantly affected by the cation balances in the external solution, however, there was not a clear tendency as to the effect of each cation in the mixture; nonetheless, the internal K⁺: Ca⁺²: Mg⁺² balances were affected by the balances in the nutrient solution, as in the shoot they were located in a very specific area of the explored space, indicating that anthurium plants accumulated more Mg⁺² compared to what it is in the external solution, whereas Ca⁺² was lower than that of the external solution. Plants accumulated K⁺ at high rates regardless of the external balance. In conclusion, the optimum nutrient solutions for anthurium may contain very wide ratios of K⁺ as long Ca⁺² and Mg⁺² are maintained at low proportion in the nutrient solution.