酚酸类物质对三七幼苗的化感影响

该文研究了不同浓度的阿魏酸、对香豆酸、丁香酸、对羟基苯甲酸、香草酸5种酚酸类物质对三七幼苗生长和生理的影响。结果表明:处理后,三七幼苗的苗高、根长、可溶性蛋白质含量、根系活力、CAT以及POD活性均有所降低。其中,阿魏酸各处理组幼苗的苗高及POD活性均显著降低,50、100 mg·L~(-1)的对香豆酸以及100 mg·L~(-1)的香草酸处理组幼苗苗高也分别比对照显著降低16.19%、16.67%和29.29%;对香豆酸、丁香酸以及对羟基苯甲酸各处理组幼苗根长均显著低于对照;香草酸处理组幼苗的根系活力也显著低于对照,且幼苗的CAT活性在10、50、100 mg·L~(-1)丁香酸、对羟基苯甲酸以及香草酸处理下也达到了显著降低水平。此外,1 mg·L~(-1)阿魏酸以及100 mg·L~(-1)香草酸处理组幼苗的叶绿素含量也均显著降低;中高浓度的阿魏酸、对香豆酸、丁香酸、对羟基苯甲酸增加了三七幼苗的MDA含量,而香草酸在0.1、1、10、100 mg·L~(-1)浓度下显著降低幼苗的MDA含量;丁香酸、香草酸、对羟基苯甲酸以及中高浓度的对香豆酸增加了三七幼苗的SOD活性,且香草酸各处理组均达到了显著性水平。综上结果表明,5种酚酸类物质对三七幼苗均具有一定的化感抑制作用,但各酚酸物质的作用方式及强度并不完全一致,阿魏酸的化感影响较大,这为进一步研究三七的化感自毒作用提供了一定的理论参考。     

不同化感物质对西瓜幼苗生长的影响

西瓜是受连作障碍影响最为严重的作物之一,由化感物质引起的自毒作用被认为是造成连作障碍的主要原因。为阐明化感物质对西瓜种子萌发及生长发育的影响,本研究选择4种最为普遍的化感物质——苯甲酸、肉桂酸、阿魏酸与丁香酸处理6个品种的西瓜种子,利用平底圆柱玻璃瓶培养法直接观察测量西瓜种子萌发以及幼苗根系与下胚轴生长动态变化。结果表明,浓度超过10 mg/L的化感物质处理显著抑制了西瓜种子的萌发和幼苗的生长,其中幼苗根系受化感物质的影响最大。不同西瓜品种对化感物质的响应差异显著,苯甲酸、肉桂酸处理后,‘郑麻10号’受到的抑制作用最强,‘利丰3号’与‘新优16号’受到的抑制作用较弱;‘晋抗6号’和‘中优杂1号’受阿魏酸、丁香酸的抑制作用最强,但这2种化感物质对‘新优16号’的抑制作用相对较弱。总体上,化感物质对西瓜抑制效果从强到弱依次为苯甲酸肉桂酸阿魏酸丁香酸。在所研究的材料中,‘利丰3号’与‘新优16号’对化感物质相对不敏感,可能在连作障碍防控中有一定的应用价值。     

不同外源酚酸化感物质组合对棉花种子萌发和幼苗生长的化感效应

为阐明不同外源酚酸类化感物质组合对棉花种子萌发及幼苗生长发育的化感效应, 选择在棉花连作30年土壤中检测到的对-羟基苯甲酸(P-HA)、香草醛(VA)、阿魏酸(FA)3种酚酸类化感物质, 以田间自然状态下含量为处理浓度研究对棉花种子萌发和幼苗生长的影响。结果表明: 3种酚酸化感物质对棉花种子萌发和幼苗生长有显著影响。对种子萌发有促进作用, 对幼苗生长有抑制作用,对幼苗生理酶活性有着不利影响。两种或两种以上化感物质混合时比一种酚酸化感物质对棉花的作用效果小, 说明对羟基苯甲酸、香草醛和阿魏酸三者之间存在拮抗效应。P-HA对VA和FA存在着抵消作用, 3种化感物质组合之间的拮抗效应与化感物质的浓度和作用效果密切相关。     

连作花生土壤中酚酸类物质的检测及其对花生的化感作用

研究了南方红壤区不同连作年限花生土壤中酚酸物质的种类、含量,及其对花生生长的影响。结果表明:连作花生土壤中对羟基苯甲酸、香草酸和香豆酸随着连作年限的增加而增加,连作10a后3种酚酸总量达11.09mg·kg-1干土,显著高于连作3a和6a的土壤;而土壤中香豆素和苯甲酸含量比较低,且变化没有规律。所有酚酸处理组对花生幼苗的株高和根长表现出抑制作用,对花生幼苗地下部的干鲜重均表现出"低促高抑"的特点。香草酸和香豆酸处理组对花生幼苗地上部的干鲜重表现出"低促高抑"的特点,其他处理组均表现出抑制作用。花生幼苗根系活力随着酚酸处理浓度的增加而降低,花生幼苗的超氧化物歧化酶活力(SOD)、过氧化物酶活力(POD)、丙二醛含量(MDA)则随着酚酸浓度的增加而增加。与只用茄腐镰刀菌孢子悬液浸泡花生种子的对照相比,加入酚酸后,花生种子的病原菌的感染率随着酚酸浓度的增加而增加,发芽率则随着酚酸浓度的增加而下降。以上结果说明,酚酸物质可以抑制花生幼苗的生长和提高花生的发病率,可能是因为酚酸物质破坏花生细胞膜的完整性而使病原菌入侵,影响花生生长,产生连作障碍。     

酚酸类物质对苜蓿种子萌发及抗氧化物酶活性的影响

实验选用紫花苜蓿体内的4种化感物质包括阿魏酸、香豆素、香草酸、香豆酸,以10-3、10-4、10-5mol·L-1和10-6mol·L-1四个浓度,采用培养皿试纸法和沙培法进行苜蓿种子萌发及幼苗生长试验,研究了苜蓿种子萌发和幼苗生长以及抗氧化保护性酶活性的变化,并就生物量、种子萌发和酶活性等三大指标的敏感性进行了讨论。结果表明,4种化感物质对苜蓿种子萌发及幼苗生长有明显的影响作用,这种影响效应与化感物质的种类及浓度显著相关。其中,10-3mol·L-1的4种化感物质均表现出对苜蓿种子萌发有显著的抑制作用,阿魏酸、香豆素和香草酸达到了极显著的抑制效果。当浓度为10-3mol·L-1时,除香豆酸外,其它3种化感物质均表现出对幼苗体内超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸酶(APX)活性有显著的抑制作用,同时使幼苗体内丙二醛(MDA)的含量显著增加;随着浓度的降低,化感物质抑制作用减弱;当浓度降低为10-6mol·L-1时,阿魏酸、香豆素、香草酸则表现出了对上述各种酶活性的轻微促进作用。阿魏酸表现出的化感效应最强,香豆素、香草酸次之,香豆酸最弱。发芽指标受化感物质的影响最敏感、其次是生物量指标,而酶活性指标相对较弱。     

叶损伤诱导兴安落叶松针叶中10种酚酸的变化

酚酸是一类重要次生抗虫物质.为研究损伤及昆虫取食诱导对兴安落叶松针叶内酚酸含量的影响,采用3种不同程度剪叶或落叶松毛虫幼虫取食处理兴安落叶松幼树,以高效液相色谱技术测定兴安落叶松健康针叶中酚酸含量.结果表明：与对照相比,处理后1 d,剪叶或昆虫取食4枝50%针叶处理的兴安落叶松幼苗健康针叶中,除阿魏酸无显著差异外,苯甲酸、咖啡酸、绿原酸、水杨酸、苯乙酸、肉桂酸、香草酸、丁香酸和没食子酸9种酚酸均差异显著;4枝75%针叶处理的10种酚酸含量均发生显著变化.说明剪叶及虫害50%、75%针叶处理均达到诱导阈值,能显著诱导兴安落叶松化学防御.在损伤程度相同情况下,处理1 d时,剪叶4枝50%、75%诱导的咖啡酸、苯乙酸、肉桂酸、香草酸和没食子酸的含量显著高于虫害诱导处理;5 d时,剪叶4枝50%、75%诱导处理的这5种酚酸含量显著低于虫害诱导处理;10 d时,两种方法诱导的酚酸含量差异不显著.说明剪叶诱导处理的酚酸含量变化比昆虫取食处理迅速,且诱导强度与剪叶程度相关.采用适当处理诱导针叶中酚酸含量的变化来增强兴安落叶松对害虫的防御能力是可行的.     

PEG模拟干旱胁迫对栓皮栎种子萌发及生长生理的影响

为了阐明栓皮栎种子萌发期对水分胁迫的耐受性,以当年采集的栓皮栎种子为材料,采用培养皿滤纸萌发的方法研究了不同浓度（0%、5%、10%、20%、30%）PEG-6000溶液对其种子萌发、生长、保护酶活性和有机渗透调节物质的影响,并对种子萌发率、胚根生长速率等与PEG浓度进行了回归分析。结果表明:（1）随着干旱胁迫程度的加剧,栓皮栎种子的发芽率、发芽指数、胚根长度、胚根生长速率和活力指数均呈先升高后下降趋势,说明低浓度（5%、10%）PEG胁迫可以促进栓皮栎种子萌发及生长,而高浓度（20%、30%）则具有抑制作用。（2）建立水分胁迫条件下种子萌发率、胚根生长速率等与PEG浓度的回归方程发现,栓皮栎种子在PEG胁迫下的萌发临界值和极限值分别为32.01%和36.99%,胚根生长速率的临界值和极限值分别为30.1%和33.35%。（3）随着PEG浓度的升高,栓皮栎种子中3种保护酶（SOD、POD、CAT）活性和3种有机渗透调节物质（可溶性蛋白、脯氨酸、可溶性糖）含量呈现不同的变化,但均有不同程度升高趋势。由此可见,栓皮栎种子可通过增加保护酶活性和体内渗透调节物质来适应水分胁迫环境,使自身萌发和生长受抑制程度降到最低。     

甜瓜根系分泌物中酚酸物质对尖孢镰孢菌的化感效应

采用HPLC法对甜瓜根系分泌物进行分离鉴定,检测到甜瓜根系分泌物中含有没食子酸、邻苯二甲酸、丁香酸、水杨酸、阿魏酸、苯甲酸和肉桂酸7种酚酸物质,通过外源添加法研究该类物质对尖孢镰孢菌的化感效应.室内试验结果表明: 阿魏酸、苯甲酸、肉桂酸在0.1、0.25 mmol·L^-1处理浓度下能够显著促进尖孢镰孢菌的孢子萌发,水杨酸则对孢子萌发具有一定的抑制作用;丁香酸、阿魏酸在菌丝培养后期表现出较强的促进作用.盆栽结果显示,在0.05、0.1和0.5 mmol·L^-1处理浓度下肉桂酸、阿魏酸、苯甲酸可显著促进甜瓜枯萎病病情.
     

西南獐芽菜种子萌发对温度、光照和外源生长调节物质的响应

研究不同温度、光照和外源生长调节物质处理种子对西南獐芽菜种子萌发特性的结果表明,西南獐芽菜种子为休眠型种子,其最适合萌发温度为20℃。光照促进种子的萌发,但影响并不显著。低浓度（10mg·L-1）6-BA促进西南獐芽菜种子萌发,而高浓度（50mg·L-1）的则抑制其萌发,不同浓度和浸种时间的赤霉素（GA）和IAA均促进种子萌发,GA的效果更好。     

重茬地黄土壤酚酸的动态积累及其对地黄生长的影响

为了探究酚酸物质与地黄连作障碍之间的关系,检测了重茬地黄土壤中阿魏酸、香草酸、香草醛和对羟基苯甲酸等4种酚酸物质的积累量,并通过水培条件下添加酚酸,研究了4种酚酸对地黄生长的影响。结果表明：阿魏酸、香草酸和香草醛含量在地黄生长期表现为持续增加,而对羟基苯甲酸含量先升高后降低;外加阿魏酸（8 μg·ml^-1）、香草酸（0.8 μg·ml^-1）、香草醛（1.2 μg·ml^-1）和对羟基苯甲酸（3.0 μg·ml^-1）对水培地黄根长、根质量、全株鲜质量和株高有较强的抑制作用;酚酸处理使地黄叶片叶绿素含量降低,除对羟基苯甲酸外差异性极显著;经过酚酸处理的地黄幼苗SOD和POD活性为先升高后下降,丙二醛含量升高,其中阿魏酸的处理使根中酶活性降至最低,根部腐烂死亡。推测4种酚酸可能是造成地黄化感作用的物质。     

Allelopathic activity of different plant parts of <Emphasis Type="Italic">Peganum harmala</Emphasis> L. and identification of their growth inhibitors substances

This study was conducted to evaluate the inhibitory potential of P. harmala leaf, stem and root extract on germination and growth of Avena fatua L. and Convolvulus arvensis L., as well as identification of the phytotoxic substances responsible for this activity. According to our results, the degree of toxicity of different P. harmala plant parts can be arranged in the following order: leaves > stems > roots. The two test species differed in their sensitivity to P. harmala extracts. Inhibitory effect on shoot length and seedling dry weight was more pronounced in C. arvensis, whereas higher reduction in germination, root length and total chlorophyll content occurred in A. fatua. A significant amount of water-soluble phenolic acids were found in P. harmala plant extracts. Total phenolic acids content was higher in leaf extracts when compared to that of stem or root extracts. Seven phenolic acids including gallic acid, vanillic acid, 4-hydroxybenzoic acid, 3,4-dihydroxybenzoic acid, caffeic acid, syringic acid and ferulic acid were found in P. harmala leaf extracts. On the other hand, we identified four phenolic acids from stem (galllic acid, vanillic acid, 3,4-dihydroxybenzoic acid and caffeic acid) and root (galllic acid, 4-hydroxybenzoic acid, syringic acid and cinnamic acid) extracts. The greater number of growth inhibitors detected in the leaves might explain the stronger inhibitory activity. Overall, our results suggest that P. harmala might be used as a natural herbicide for weed control and consequently reduce dependence on synthetic herbicides.     

Seasonal fluctuations in soil phenolics of a coniferous forest: effects on seed germination of different coniferous species

This study examined seasonal variations in the content of water-soluble phenolics extracted from litter and Ah horizon of forest soil under Pinus laricio Poiret trees. After having identified and quantified different phenolics, the effects of seasonal phenolic extracts, single phenolic acids and synthetic phenol mixtures on seed germination of Pinus laricio Poiret, Pinus pinaster Aiton and Pinus halepensis Mill. were evaluated, and the activity of phenolics on the main enzymes involved in the glyoxylate cycle was tested. The results indicated a seasonal variation of phenol content in soil, with largest concentrations of water-soluble phenolic acids in autumn and smallest concentrations in summer. Addition of phenol extracts to germination medium reduced seed germination showing phytotoxic effects which differed, depending on the species and the fractions tested. Phenols extracted from litter and Ah horizon in autumn and winter, vanillic acid, and synthetic mixtures reproducing phenols extracted from soil in winter inhibited seed germination of Pinus laricio, pinaster and halepensis more than other treatments. A greater inhibitory effect was observed on seed germination of Pinus pinaster and halepensis compared to Pinus laricio. The phenols also had the greatest inhibitory effect on glyoxylic enzyme activities. Section Editor: H. Lambers     

Studies on Flavor Components in Soybean

Ethanol (1:1) extract of defatted soybean flour was fractionated systematically and the resulting phonolic acid fraction was investigated. This fraction had strong phenol-like flavor and contained at least seven phenolic acids including syringic, vanillic, ferulic, gentisic, salicylic, p-coumaric, and p-hydroxybenzoic acids. The main component among these was syringic acid, which was isolated as 3,5-dinitrobenzoate.

In addition, two isomers of chlorogenic acids, presumably isochlorogenic and chlorogenic acids approximately in a ratio of 1 : 10, were found in this extract. These substances have sour, bitter and astringent flavors.     

Inhibition behaviours of some phenolic acids on rat kidney aldose reductase enzyme: an in vitro study

Aldose reductase (AR) inhibitors have vital importance in the treatment and prevention of diabetic complications. In this study, rat kidney AR was purified 19.34-fold with a yield of 3.49% and a specific activity of 0.88?U/mg using DE-52 Cellulose anion exchange chromatography, gel filtration chromatography and 2′5′ ADP Sepharose-4B affinity chromatography, respectively. After purification, the in vitro inhibition effects of some phenolic acids (tannic acid, chlorogenic acid, sinapic acid, protocatechuic acid, 4-hydroxybenzoic acid, p-coumaric acid, ferulic acid, vanillic acid, syringic acid, α-resorcylic acid, 3-hydroxybenzoic acid and gallic acid) were investigated on purified enzyme. We determined IC₅₀, K_i values and inhibition types of these phenolic acids. As a result, tannic and chlorogenic acid had a strong inhibition effect. On the other hand, gallic acid had a weak inhibition effect. In this study, all phenolic acids except for chlorogenic acid and p-coumaric acid showed non-competitive inhibition effects on rat kidney AR.     

Changes in Phenolic Acid Content During Alternaria alternata Infection in Tomato Fruit

Phenolic acids are components of the plant defence system; however few studies had been done with fruits. The objective of this experiment was to elucidate the changes in phenolic acid content in tomato fruits in response to pathogenic attack. Tomato fruit ‘Pinto’ was inoculated with spores of Alternaria alternata and stored for 10 days at 25°C and 90–92% of relative humidity. Sampling of epicarp and mesocarp tissues of control and infected tomato fruits were done every 2 days. Phenolic acids were extracted from each tissue and identified by HPLC coupled to a mass spectrometer. Quantification was done based in standard curves. In vitro evaluation of the phenolic acid effect either one‐by‐one and in a mixture of phenolic acids (MPA) over A. alternata spore germination was done with 25, 50, 100, 200 and 500 mm . It was found caffeic, chlorogenic and vanillic acids in both epicarp and mesocarp tomato tissues before the beginning of the experiment. Infected tomato fruits showed significantly higher concentrations of vanillic acid in the epicarp, only. Chlorogenic acid and the MPA inhibit spore germination by 30%, whereas caffeic acid and vanillic acid inhibit 16% at 500 mm . It was concluded that chlorogenic, vanillic and caffeic acids are phytoanticipins in tomato fruit. The concentration of vanillic acid also increases in tomato fruit epicarp as part of the defence system during a pathogenic attack.     

Composition and Bioactivity of Lipophilic Metabolites from Needles and Twigs of Korean and Siberian Pines (Pinus koraiensis Siebold & Zucc. and Pinus sibirica Du Tour)

Lipophilic extractive metabolites in different parts of the shoot system (needles and defoliated twigs) of Korean pine, Pinus koraiensis, and Siberian pine, Pinus sibirica, were studied by GC/MS. Korean pine needles comprised mainly bornyl p‐coumarate, heterocyclic 15‐O‐functionalized labdane type acids (lambertianic acid), 10‐nonacosanol, sterols and their esters. While Siberian pine needles contained less bornyl p‐coumarate, lambertianic acid, sterols and their esters, but were richer in other 15‐O‐functionalized labdane type acids. The major components of the twig extract of P. koraiensis were lambertianic acid, abietane and isopimarane type acids, cembrane type alcohols, 8‐O‐functionalized labdanoids, sterols, sterol esters, and acylglycerols. The same extract of P. sibirica differed in larger amounts of other 15‐O‐functionalized labdane type acids and pinolenic acid glycerides, but in less quantities of cembranoids and 8‐O‐functionalized labdanoids. The labdane type pinusolic acid was detected for the first time in Korean pine. P. koraiensis was found to be unique in the genus for an ability to synthesize phyllocladane diterpenoids. The content of bound Δ⁵‐unsaturated polymethylene‐interrupted fatty acids in the twig extracts of the both pines was similar or superior to that in their seed oil. Among the pines’ metabolites tested isocembrol was strongest in inhibition of both α‐glucosidase (IC₅₀ 2.9 μg/ml) and NO production in activated macrophages (IC₅₀ 3.6 μg/ml).     

The effect of phenols on respiratory enzymes in seed germination

Low molecular weight phenolic compounds were identified in two soilswith different vegetative cover, Fagus sylvatica, L. andPinus laricio, Poiret, spp. calabrica, and were tested atdifferent concentrations on seed germination of Pinuslaricio, and on respiratory and oxidative pentose phosphate pathwayenzymes involved in the first steps of seed germination. The data obtained showthat there are marked differences in the phenolic acid composition of the twoinvestigated soils. All the phenolic compounds bioassayed inhibited seedgermination and those extracted from Pinus laricio soilwere particularly inhibitory. We also found that the non-germination of seedsisstrongly correlated to the inhibition of the activities of enzymes ofglycolysisand the oxidative pentose phosphate pathway.     

The effect of pH on the transformation of syringic and vanillic acids by the laccases of Rhizoctonia praticola and Trametes versicolor

Laccases (benzenediol: oxygen oxidoreductases, EC 1.10.3.2) from Rhizoctonia praticola and Trametes versicolor formed different products from syringic and vanillic acids at different pH values, but both enzymes generated the same chemicals at a particular pH. The products were separated by thin-layer and high-performance liquid chromatography. Four compounds were determined from syringic acid (m/z 168, 334, 350 and 486) at pH 6.9, but only two of these (m/z 168 and 334) were found at pH 3.5. In the case of vanillic acid two isomeric dimers (m/z 304) and 2-methoxy-1,4-benzoquinone (m/z 138) were identified. The dimers were formed at both pH values (pH 3.5 and 6.9), but 2-methoxy-1,4-benzoquinone appeared only at pH 3.5.