Effects of Copper on the Photosynthesis and Oxidative Metabolism of Amaranthus tricolor Seedlings

The objective of the present study was to gain better insight into the physiological mechanisms on the effects of copper （Cu） on photosynthesis and active oxygen metabolism in three-colored amaranth plant （Amaranthus tricolor）. Three- colored amaranth seedlings were subjected to different Cu levels in soils during the entire experimental period. The parameters of growth, photosynthesis, mineral elements contents, and active oxygen metabolism were investigated using plant physiological methods. The results showed that 2.0 and 4.0 mmol Cu kg^-1 treatments decreased the whole plant biomass to 91 and 73% of the control, respectively. The net photosynthetic rate （Pn） and the stomatal conductance （gs） were similarly reduced in the third leaves of three-colored amaranth seedlings treated with 2.0 and 4.0 mmol Cu kg^-1 soil, respectively. None of the investigated Cu levels decreased the internal CO2 concentration （Ci）. The effect of Cu on the potential efficiency of photosystem Ⅱ （Fv/Fm） was negligible, whereas the effect of Cu on the PS Ⅱ quantum efficiency （ΦPS Ⅱ） after plant adaptation in actinic irradiation was more noticeable. On the other hand, decreases in water percentage, contents of photosynthetic pigments and mineral elements including Fe, K, and Mg, and significant increase in the Cu content were observed in the third leaves of Cu-treated plants. Superoxide dismutase （SOD） and peroxidase （POD） activities as well as the proline （Pro） content significantly increased in the third leaves of the three-colored amaranth seedlings treated with 2.0 and 4.0 mmol Cu kg^-1 soil, while catalase （CAT） and ascorbate peroxidase （APX） activities as well as the contents of carotenoid （Car）, glutathione （GSH）, and ascorbic acid （AsA） decreased, and accompanied by the increases in the contents of hydrogen peroxide （H2O2）, superoxide anion （O2^-）, and malondialdehyde （MDA）, and electrolyte leakage. As a result of the imbalance of active oxygen metabolism, Pn and ΦPS Ⅱ decreased, and peroxidization enhanced under levels of 2.0 and 4.0 mmol Cu kg^-1 soil. Finally, the growth of three-colored amaranth plant was significantly inhibited.

Isolation of a choline monooxygenase cDNA clone from Amaranthus tricolor and its expressions under stress conditions

Plants synthesize the osmoprotectant glycine betaine (GB) via choline→betaine aldehyde→glycine be- taine[1]. Two enzymes are involved in the pathway choline monooxygenase (CMO) and betaine aldehyde dehydrogenase (BADH). A full length CMO cDNA (1,643bp) was cloned from Amaranthus tricolor. The open reading frame encoded a 442-amino acid polypeptide, which showed 69% identity with CMOs in Spina- cia oleracea L. and Beta vulgaris L. DNA gel blot analysis indicated the presence of one copy of CMO gene in the A. tricolor genome. The expressions of CMO and BADH proteins in A.tricolor leaves significantly increased under salinization, drought and heat stress (42℃), as determined by immunoblot analysis, but did not respond to cold stress (4℃), or exogenous ABA application. The increase of GB content in leaves was parallel to CMO and BADH contents.

不同积累型苋菜(Amaranthus mangostanus L.)镉吸收转运特征差异性研究

【目的】比较高积累型苋菜品种Tianxingmi与低积累型苋菜品种Zibeixian在Cd胁迫下Cd吸收转运特征差异性,揭示苋菜品种Tianxingmi高积累镉的机理。【方法】采用水培试验,添加代谢抑制剂来研究两品种苋菜根系吸收Cd的主要途径。分别在30μmol/L Cd Cl2处理4 h、8 h、16 h、1 d和2 d采样测定,采用非损伤微测技术(Non-invasive micro-test technique,NMT),进行植物活体动态测试,调查、测量两品种苋菜根系Cd^(2+)离子流特征,比较了两品种对代谢抑制剂的反应。【结果】在30μmol/L Cd Cl2处理1 d后,Tianxingmi生物量达到最大值5.90 g/plant,是Zibeixian生物量的二倍;Tianxingmi根、茎和叶中Cd浓度分别为609、254和62.3mg/kg,分别是Zibeixian的1.4倍、1.9倍和1.6倍,地上部和全株的Cd累积量分别高达602.0、1308μg/plant;Tianxingmi富集系数(BCF)与转运系数(TF)分别为Zibeixian的2.1倍和1.5倍,这些结果两品种均表现出显著性差异(P<0.05)。NMT技术测定两品种根系Cd^(2+)离子流,通过扫描位点测定发现,距根尖0~300μm范围内两品种苋菜根系Cd^(2+)内流最强且差别最大,并在此做定点位点测定,发现Tianxingmi根系Cd^(2+)内流是Zibeixian根系Cd^(2+)内流的3.75倍,说明了两品种的富集特征与NMT结果一致。添加代谢抑制剂处理显著降低了高积累型Tianxingmi各器官中的Cd浓度,富集系数(BCF)与转运系数(TF),以及根系Cd^(2+)内流(P<0.05),主动吸收特征明显,而对低积累型Zibeixian的相关生理指标影响不大。【结论】两苋菜品种Cd吸收转运特征均表现出显著性差异。Tianxingmi具有更强的Cd吸收和向地上部转运与累积能力,并且根系对Cd的吸收与转运是主动需能的过程,共质体途径在Cd进入Tianxingmi根系并向地上部运输的过程中起着主要作用。

Bioassay and Characterization of Several Palmer Amaranth (<i>Amaranthus palmeri</i>) Biotypes with Varying Tolerances to Glyphosate

The wide distribution of Palmer amaranth (Amaranthus palmeri) in the southern US became a serious weed control problem prior to the extensive use of glyphosate-resistant crops. Currently glyphosate-resistant populations of Palmer amaranth occur in many areas of this geographic region creating an even more serious threat to crop production. Investigations were undertaken using four biotypes (one glyphosate-sensitive, one resistant from Georgia and two of unknown tolerance from Mississippi) of Palmer amaranth to assess bioassay techniques for the rapid detection and level of resistance in populations of this weed. These plants were characterized with respect to chlorophyll, betalain, and protein levels and immunological responses to an antibody of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) the target site of glyphosate. Only slight differences were found in four biotypes grown under greenhouse conditions regarding extractable soluble protein and chlorophyll content, but one biotype was found to be devoid of the red pigment, betalain. Measurement of early growth (seedling shoot elongation) of seedlings was a useful detection tool to determine glyphosate resistance. A leaf disc bioassay (using visual ratings and/or chlorophyll analysis) and an assay for shikimate accumulation were effective methods for determining herbicide resistance levels. The two unknown biotypes were found to be resistant to this herbicide. Some differences were found in the protein profiles of the biotypes, and western blots demonstrated a weak labeling of antibody in the glyphosate-sensitive biotype, whereas strong labeling occurred in the resistant plants. This latter point supports research by others, that increased copy number of the EPSPS gene (and increased EPSPS protein levels) is the resistance mechanism in this species. Results indicate the utility of certain bioassays for the determination of resistance and provide useful comparative information on the levels of inherent constituents among closely related plants.

Target Site-Based Resistance to ALS Inhibitors, Glyphosate, and PPO Inhibitors in an <i>Amaranthus palmeri</i>Accession from Mississippi

Extensive acceptance of glyphosate-resistant (GR) row crops coupled with the simultaneous increase in glyphosate usage has sped the evolution of glyphosate resistance in economically important weeds. GR Amaranthus palmeri populations are widespread across the state with some exhibiting multiple resistance to acetolactate synthase (ALS) inhibiting herbicides such as pyrithiobac. A GR and ALS inhibitor-resistant accession was also resistant to the protoporphyrinogen oxidase (PPO) inhibiting herbicide fomesafen. The PPO inhibitor resistance profile and multiple herbicide resistance mechanisms in this accession were investigated. In addition to fomesafen, resistance to postemergence applications of acifluorfen, lactofen, carfentrazone, and sulfentrazone was confirmed. There was no resistance to preemergence application of fomesafen, flumioxazin, or oxyfluorfen. Molecular analysis of the ALS gene indicated the presence of point mutations leading to single nucleotide substitutions at codons 197, 377, 574, and 653, resulting in proline-to-serine, arginine-to-glutamine, tryptophan-to-leucine, and serine-to-asparagine replacements, respectively. The resistant accession contained up to 87-fold more copies of the EPSPS gene compared to a susceptible accession. A mutation leading to a deletion of glycine at codon 210 (ΔG210) of PPO2 gene was also detected. These results indicate that the mechanism of resistance in the Palmer amaranth accession is target-site based, i.e., altered target site for ALS and PPO inhibitor resistance and gene amplification for glyphosate resistance.

Interaction of the Bioherbicide <i>Myrothecium verrucaria</i>with Technical-Grade Glyphosate on Glyphosate-Susceptible and -Resistant Palmer Amaranth

Previously we found that a strain of Myrothecium verrucaria (MV) exhibited bioherbicidal activity against several important weeds, and that some commercial formulations of glyphosate applied with MV resulted in synergistic interactions that improved weed control efficacy. We also found that MV had bioherbicidal activity against glyphosate-resistant Palmer amaranth. We have also reported that some commercial formulations are inhibitory to MV. Our objectives were to test the effect of unformulated glyphosate (high purity, technical-grade glyphosate) alone and in combination with MV for bioherbicidal activity on glyphosate-susceptible and -resistant Palmer amaranth biotypes under greenhouse conditions and to examine technical-grade glyphosate on the growth of this bioherbicide. High purity glyphosate (without adjuvants/surfactants) was not toxic to MV growth and sporulation at concentrations up to 2.0 mM when grown on agar supplemented with the herbicide. Both biotypes were injured by MV and MV plus glyphosate treatments as early as 19 h after application (3 h after a dew period of 16 h). These injury effects increased and were more evident through the 6-day time course, when after 120 h the MV plus glyphosate treatment had killed all glyphosate-susceptible and -resistant plants. The interaction of glyphosate plus MV was synergistic toward the control of Palmer amaranth. Data strongly suggest that the active ingredient is responsible for the synergy previously found when this bioherbicide was combined with some commercial formulations of glyphosate. Results demonstrated that MV can control both glyphosate-resistant and -susceptible Palmer amaranth seedlings and act synergistically with high-purity glyphosate to provide improved weed control.

Genomic Stability of Palmer amaranth Plants Derived by Macro-Vegetative Propagation

qPCR (quantitative polymerase chain reaction) and random amplified polymorphic DNA (RAPD) were utilized to investigate genetic stability of Palmer amaranth cloned plants over 10 generations. DNA from original parent Palmer amaranth plants (grown from seeds) was re-analyzed using qPCR, and confidence levels for determining ΔΔCt (threshold crossing) values were established. ANOVA was used to determine variation (margin of error) of these ΔΔCt values. This margin of error was applied to qPCR analysis of DNA from eight individual parent plants and their descendants (10th generation) so that possible differences in EPSPS (5-enolpyruvylshikimate-3-phosphate synthase) gene copy number could be ascertained. This method (and the associated error) indicated a lack of agreement in ΔΔCt values of DNA from plants of these two generations. qPCR analysis showed that in five out of eight clones, EPSPS gene copy number varied more than the calculated error (P = 0.05). A second technique to monitor genetic stability, RAPD was used to determine possible changes in genomic DNA due to extended cloning of these regenerated plants. RAPD analysis showed that four out of the eight clones differed when the profiles of the two generations were compared. Results show that qPCR and RAPD analysis point to the fact that several Palmer amaranth clones experienced changes in genome structure over 10 generations. Although the glyphosate resistance trait was retained, results suggest that during cloning studies, the genetic stability of macro-vegetatively propagated lines should be monitored.

红苋菜总黄酮超声波辅助提取工艺优化及其抗氧化、抑菌活性

该文以红苋菜为原料,75%乙醇为提取溶剂,利用超声波法优化红苋菜总黄酮的提取工艺,并对其抗氧化活性及抑菌机制进行探究。结果表明:优化的红苋菜总黄酮提取工艺参数分别为料液比1∶40(g/mL)、提取时间2.0 h、提取温度70℃,在此条件下获得的总黄酮提取量为1.498 mg/g。红苋菜总黄酮清除DPPH自由基的IC_(50)值为(38.5±0.6)μg/mL,当红苋菜总黄酮质量浓度为80.00 μg/mL时,对Fe^(3+)的还原能力与阳性对照抗坏血酸接近,红苋菜总黄酮对金黄色葡萄球菌的抑制效果明显,最小抑菌浓度为40.00 mg/mL。随着红苋菜总黄酮质量浓度的增加,细菌培养液中电导率增大,DNA及RNA大分子物质浓度上升,说明红苋菜具有良好的抗氧化活性和抑菌活性。

生物炭有机肥部分替代化肥对苋菜生长、产量、品质和氮素利用率的影响

为探究化肥减施潜力和生物炭有机肥增效作用,缓解因化肥过量施用导致的蔬菜品质下降和肥料利用率降低等问题,以苋菜为试材,设6个施肥处理:不施肥(CK1)、100%常规施肥(CK2)、85%常规施肥+2250 kg·hm^(-2)生物炭有机肥(T1)、85%常规施肥+4500 kg·hm^(-2)生物炭有机肥(T2)、70%常规施肥+4500 kg·hm^(-2)生物炭有机肥(T3)、70%常规施肥+2250 kg·hm^(-2)生物炭有机肥(T4),对比分析各处理苋菜生长、产量、品质、氮肥吸收及利用的差异。结果表明,与CK1相比,施肥不同程度促进苋菜植株生长,增加苋菜根茎叶氮素积累量,苋菜产量提高5.83%~22.67%。与CK2相比,生物炭有机肥部分替代化肥显著增加苋菜的生物量,提升可溶性糖、可溶性蛋白和维生素C含量,降低硝酸盐和有机酸含量;其中,T1和T2苋菜产量分别提高7.28%和11.87%,T2氮肥吸收利用率和氮肥农学利用率分别提升16.74%、21.48 kg·kg^(-1)。综上,T2为最优处理,可促进苋菜生长,提高苋菜产量和氮素利用率,改善品质,是实现肥料高效利用、减肥增效的良好施肥模式。

Study of the Potassium Content in Amaranth Protein Using the Gamma Spectrometry Technique

Amaranthus is a dicotyledonous pseudocereal and one of the new world’s oldest crops,having originated from Meso-America and was a major food crop of the Aztecs.Popularity in the cultivation and consumption of Amaranthus seed in the modern era began in the mid-1970s with the rediscovery and promotion of amaranth due to its superior nutritional attributes as compared to cereal grains.Amaranth plant has a high-quality protein,carbohydrates,unsaturated oil,squalene,dietary fiber,tocopherols,phenolic compounds,flavonoids,vitamins and minerals.The amaranth’s grain was collected at San Martin Pahuacan,Estado de Mexico,Mexico.The used methodology is gamma spectrometry with Hyperpure Germanium detector(HPGe)and Multichannel Analyzer(MCA)with Maestro software.The result shows a unique concentration of radioactive potassium content in the amaranth protein isolated from amaranth grains is 424.1 mg/100 g of amaranth protein.There is an excellent agreement between the amount of potassium determined by atomic absorption spectroscopy in our laboratory and the value obtained in this work using the Gamma Spectrometry Technique.

基于表型性状的老鸦谷种质遗传多样性分析

本研究以收集保存的236份老鸦谷(Amaranthus cruentus)种质资源为材料,对其19个表型性状进行遗传多样性、主成分分析、相关性分析和聚类分析。结果表明:供试的老鸦谷种质具有丰富的遗传多样性,质量性状中遗传多样性指数最高的为主花序颜色(1.421),数量性状中遗传多样性指数最高的为株高(2.070),变异系数最大的为主茎分枝数(97.11%);提取的2个主成分累计贡献率为61.60%,第一主成分主要反映老鸦谷的叶长和叶宽,第二主成分主要反映老鸦谷主花序长度及主花序分枝数。聚类分析将供试材料分为5类,其中Ⅰ~Ⅴ类分别包含64,68,42,36,26份种质资源,Ⅰ类的生物量相关性状最佳,可作为饲草育种材料,IV类和V类颜色较为鲜艳,可用于观赏材料的筛选。本研究可为老鸦谷优异种质筛选、资源保护、品种的选育和改良提供重要参考。

鸡粪和垃圾有机肥对苋菜生长及土壤重金属积累的影响

采用盆栽试验,在红壤和潮土中分别施入土壤重量5%、10%和15%的鸡粪或垃圾有机肥,研究其对苋菜（Amaranthustricoclor L.）生长、土壤化学性状及重金属含量的影响。结果表明,与对照相比,施入鸡粪或垃圾有机肥显著增加苋菜的鲜重、主根长和株高;土壤有机质、EC值、速效磷和速效钾含量均大幅增加,但土壤全氮含量无明显变化。与对照相比,潮土中施用两类有机肥使苋菜植株Cu和Zn含量分别增加26.3%~36.0%和1.2%~20.3%,但未超出国家食品卫生标准对Cu和Zn的允许含量;Cd、Cr和Pb含量都较对照降低,没有出现积累现象。红壤施用两类有机肥,苋菜植株中Zn、Cd和Pb分别下降42.7%~59.9%、0~48.9%和4.1%~71.3%,达到显著水平。有机肥的施入量为5%时,两类土壤中重金属都没有出现明显积累;当施入量为10%和15%时,两类土壤的Cu、Cd、Cr和Pb含量显著增加,出现明显积累趋势,其中除了施用鸡粪使土壤有效Cu含量下降外,两种有机肥均增加了两类土壤中重金属Zn、Cd、Cr和Pb的有效态含量。试验结果提示,从土壤培肥与环境质量安全综合考虑,有机肥的用量应控制在一个适宜范围内。

高温下花红苋和绿叶苋叶片生理特性变化的比较

40℃连续6 d处理苋菜(Amaranthus tricolor)两个栽培品种花红苋和绿叶苋,探讨热胁迫下它们生理特性的改变。结果表明:与绿叶苋相比,高温下花红苋叶中可溶性糖和脯氨酸含量明显增加,PPO(多酚氧化酶)和POD(过氧化物酶)活性增强,苋菜红素显著积累。绿叶苋对高温表现敏感,苋菜红素含量在处理2 d后明显降低,膜脂过氧化产物丙二醛和质膜透性均高于花红苋,叶片呈现较明显的氧化漂白症状。与常温对照相比,高温下两种苋菜的总酚含量变化不大。热胁迫下花红苋积累较多的苋菜红素和渗透调节物质,酶活性提高,可能是其对高温逆境具有较好耐受能力的生理基础。

环境因子对春季大棚早熟苋菜营养生长的影响

研究了塑料大棚内的光照强度、气温、地温、二氧化碳浓度及氮肥施量5五个环境因子五水平的处理组合对春苋菜早熟栽培营养生长的影响,结果表明,不同处理组合对苋菜茎高,茎粗,叶片面积、厚度,植株干重,根系活力及叶绿素含量等指标有着极显著的影响;处理B(0网1膜)的综合环境最为优越,以处理A(0网0膜)为对照,B的茎高增加了127.1%,茎粗72.1%,叶片面积248.7%,叶片厚度7.7%,鲜重308.2%,干重218.6%,根系总吸收面积152.7%,活跃吸收面积231.1%,总叶绿素含量16%;处理C(1网1膜)、D(2网1膜)和E(3网1膜)的各营养生长指标都有不同程度的降低。光照强度是早春大棚苋菜能否获得高产的首要因子,弱光下盲目施用CO2可能导致不经济;苋菜在高强度光照或高浓度CO2下栽培,需要配合高水平氮;严重遮荫时,高水平氮相对过剩,反而不如低水平氮更易获得高产。

苋菜甜菜红素合成相关基因AmMYB1的克隆及表达分析

应用RACE技术,从‘大红’苋菜中克隆到1条MYB基因cDNA全长序列,命名为AmMYB1(登录号为KU557504)。AmMYB1基因开放阅读框为723bp,可编码240个氨基酸。其基因组序列与cDNA比对后显示,AmMYB1基因含有1个内含子。生物信息学分析表明,AmMYB1具有2个连续的MYB结构域,是一个典型的R2R3-MYB;同源分析显示,该基因编码的氨基酸序列与甜菜红素相关BvMYB1的一致性最高,达到54%。亚细胞定位结果显示,AmMYB1蛋白定位于细胞核。实时荧光定量PCR分析表明,AmMYB1基因在‘大红’苋菜叶片红色部位的表达量高于绿色部位;在甜菜红素含量高的叶和茎中表达量明显高于根;在光照条件下表达量高于遮光处理;在红叶品种中的表达量高于绿叶品种。研究结果表明,AmMYB1基因可能是苋菜甜菜红素合成途径中重要的正调控因子。

籽粒苋幼苗对不同盐离子胁迫响应的比较研究

比较研究了等渗(-0.096,-0.198,-0.437MPa)的NaCl、Cl盐和Na盐处理10d对籽粒苋幼苗干重、生长速率、叶绿素含量、光合作用特性及离子吸收分布的影响。结果表明,-0.096和-0.198MPaCl盐显著促进植株干重,-0.198和-0.437MPa盐胁迫下,对籽粒苋幼苗生长抑制幅度由大到小依次为Na盐>NaCl>Cl盐处理。高盐(-0.437MPa)胁迫下,对籽粒苋幼苗净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)的抑制幅度由大到小次序为Na盐>NaCl>Cl盐处理。NaCl和Na盐胁迫下,籽粒苋幼苗植株根和茎中Na+含量均高于叶中Na+含量,将Na+更多的截留在根、茎中。不同渗透势下的NaCl、Na盐处理均显著提高根、茎、叶的SK,Na,根的SK,Na随着盐度的增加呈增加趋势。结果表明,NaCl对籽粒苋幼苗的钠胁迫作用显著大于氯胁迫的,NaCl和Na盐胁迫下植株根、茎、叶对K+的选择性吸收和运输均显著增强,赋予籽粒苋幼苗对盐的一定程度上的适应性。

苋菜红素的提取纯化及抗氧化活性分析

通过单因素和正交试验优化苋菜(Amaranthus tricolor L.)红素的提取工艺。结果表明,提取苋菜红素的最佳条件为浸提时间30 min,浸提温度40℃,料液比1∶40(g/m L),同时利用大孔树脂进行纯化,并测定苋菜红素的含量及抗氧化活性,得到苋菜红素的含量为12.5%,在一定质量浓度范围内,苋菜红素还原能力随浓度升高而增强,苋菜红素对羟自由基、亚硝酸根离子和DPPH·的最大清除率分别为54.2%、17.3%和97.2%,具有明显的抗氧化作用。

麦饭石矿物肥施用效果试验

通过盆栽种植小白菜及后茬作物苋菜,测定其农艺性状、产量及植株中矿质营养成分含量来研究麦饭石矿物肥肥效。结果表明,麦饭石矿物肥对小白菜和苋菜的茎长、根长、鲜重和矿质元素的积累均有显著影响;当矿物肥的施用量在0～0.87 g.kg-1时,随着矿物肥施用量的增加其作用明显增强,当大于0.87 g.kg-1时,其增效减缓。

铜胁迫对苋菜幼苗生长和抗氧化酶活性的影响

土培试验研究了铜胁迫对苋菜幼苗生长和抗氧化酶活性的影响。结果表明，1．0mmol／kg以上浓度铜处理明显抑制茎和根的伸长，降低干物质积累，但增加了成熟叶的干重（1．0—2．0mmol／kg）；显著增加成熟叶SOD和POD活性，降低CAT活性，并伴随MDA含量和细胞电解质渗漏增加。