人参连作土壤对不同生育期人参生长发育及抗氧化系统的影响

人参产业是吉林省的特色支柱健康产业,但由于人参连作障碍的限制,使得人参产业面临着资源枯竭。通过探究人参连作土壤对正常人参生长发育的影响,研究破解人参连作障碍。以正常生长的盆栽人参样本为对照组（Control Check, CK）,以连作土壤种植人参样本为模型组（Continuous Crop obstacles, CCO）,从植物组织形态、生理生化水平和组织内抗氧化水平等3个方面,系统分析了不同生长时期连作土壤对正常人参生长发育的影响。结果表明,CCO组人参植株的株高、主根长、须根数在采收期较CK组相比具有显著差异（P<0.05）。在果实期和采收期,CCO组样本组织内过氧化氢酶（CAT）活性显著降低,丙二醛（MDA）含量显著增加（P<0.05）;在采收期,与CK组比较,CCO组人参过氧化物酶（POD）的活性显著增加（P<0.05）,超氧化物歧化酶（SOD）活性显著降低（P<0.05）,表明人参连作土壤可显著影响对正常人参植株的氧化应激水平与生长发育两个方面,如果能够通过土壤改良的方法,破解连作难题,则将有效解决吉林省的人参种植领域瓶颈问题。     

QuEChERS前处理-气相色谱-质谱法测定种植草莓的土壤中9种常见农药的残留量

<正>草莓是蔷薇科草莓属多年生草本花果,其富含丰富的维生素和矿物质,营养价值高,是大众喜爱的水果之一~([1-4])。然而,草莓植株低矮,果实鲜嫩多汁,含水量大,极易受到病虫害的感染。一些果农为了使草莓产量提高,采用土地连做方式整年生产草莓。这种生产方式导致土壤中病菌数量增多,草莓的病虫害如白粉病、灰霉病、根腐病更有增加的趋势。这种环境下农药在草莓及土壤中的降解速率均低于露天环境。近年来,国家对食品安全问题愈来愈重视,农药残留是引起食品安全问题的重要因素之一,因此,建立一种快速、便捷的方法监测农药残留已迫在眉睫~([5-8])。     

土壤无机元素与中药品质关系研究进展

综述了近几年土壤无机元素与中药品质关系的最新研究进展,主要包括土壤无机元素影响中药品质的机制研究、土壤无机元素影响中药化学成分的研究、土壤无机元素与中药道地性关系的研究,以及土壤无机元素与中药毒性关系的研究,并指出了目前研究中存在的主要问题和今后研究的主要方向。     

凝胶化土壤防渗研究

土地荒漠化是全球广泛关注的重大生态环境问题 [1] .要治理荒漠化 ,必须研究荒漠化机理 ,目前认为 [2 ] ,在沙漠化过程中存在两个过程 ,其一是地表物质中细粒部分吹蚀导致地表颗粒粗化 ,造成土壤渗透性的增加 ,加速土壤养分的损失 ;其二是丘间低地水分积聚 ,导致地下水位上升 ,在干旱高温季节 ,地下水上升蒸发 ,盐分留在地表 ,引起二次盐渍化 ,促进了沙漠化 .因此 ,上防水渗、下防盐升是治理土壤荒漠化植被的基本方法之一 [3] .中国科学院兰州沙漠研究所在科尔沁沙地进行了埋膜种稻实验 [4 ] ,证实保水膜技术行之有效 .但是 ,由于采用塑料薄…     

离子色谱法测定墓葬土壤中5种阴离子

正墓葬环境中土壤的理化性质是文物工作者发掘和出土文物的重要依据,也是影响文物是否保存完整的因素。土壤易溶盐,极易导致土质文物发生"盐害",进而使得文物出现不同程度的破坏[1]。在湿润的环境下,土壤中的SO42-、NO3-会形成对应的酸,不仅对文物造成腐蚀,还会毒害土壤中有益的微生物[2]。高氯含量的墓葬土壤会造成青铜器腐蚀、铁锚锈蚀,还会引起土壤盐渍化[3-4]。土壤中酶的活性和酸度受到氟含量的影响,当     

有机酸类化感物质的血清蛋白输运机制研究

利用亲和毛细管电泳(Affinity Capillary Electrophoresis,ACE)建立有机酸类化感物质与血清白蛋白(Bovine serum albumin,BSA)结合反应的分析方法。模拟典型有机酸类化感物质与血清白蛋白的结合反应,构建配体(有机酸)-受体(BSA)相互作用体系,采用ACE法研究不同浓度柠檬酸(Citric Acid,CA)/磺基水杨酸(Sulfosalicylic acid,SA)与BSA的结合反应机制并比较不同有机酸作用机理异同。结果表明,有机酸类化感物质CA/SA与BSA发生结合反应形成复合物CABSA和SA-BSA。依据有效淌度变化,理论方程非线性拟合结合反应的表观结合常数KCA-BSA=(1.82±0.11)×104L·mol-1、KSA-BSA=(2.12±0.12)×104L·mol-1,结合反应均为快平衡反应。相关工作阐明了血清蛋白输运有机酸类化感物质的生理作用,为化感物质与生物大分子结合反应的深入研究提供相应理论参考。     

人参、当归中微量氟的离子色谱分析

近年来,对中药研究的报道大多数侧重于有机成份的分析,而对其中无机成份研究较少。文献报道了126种中药中微量元素的系统分析,但未对人体必需的十四种微量元素之一——氟进行测定。氟是人体必需的微量元素,对牙齿及骨骼的形成和结构,以及钙和磷的代谢均有重要的作用。维持人体内部微量元素平衡的主要来源是食物和药物,为此本文选用人参和当归二种中药,用离子色谱法测定其煎剂中的微量氟,对探讨中药中微量成份的分布与疗效之问的关系有着一定的意义,人参和当归中微量氟的离子色谱分析尚未见文献报道,本文提出了一种简便、快速、准确地测定中药煎剂中微量元素氟的可靠的分析方法。     

稻米及其植株器官、环境土壤中总汞的快速测定

为了快速获得稻米及其植株器官、环境土壤等系列相关样品中总汞的含量,运用直接测汞仪测量了稻米及其植株器官、环境土壤等系列相关样品中总汞含量,建立了一种快速检测稻米及其植株器官、环境土壤中总汞的方法.优化了仪器的各项参数,最佳仪器条件为裂解温度为650℃保持40 s,释放温度900℃;验证了液体或固体标准物质作外标曲线对样...     

离子型稀土矿山浸矿土壤的氮化物迁移实验研究

赣南离子型稀土浸矿开采过程中,因大量使用(NH_4)_2SO_4作浸矿剂造成土壤氮化物累积,引发矿区土壤及水体氮化物的持续严重污染。通过模拟土柱实验,测定原矿土壤(未开采的稀土矿土壤)和一般土壤(矿山周边的普通土壤)在模拟浸矿过程中氮化物的污染含量,研究氮化物在土柱实验中的迁移特征及规律。结果表明:浸矿过程中,原矿土壤和一般土壤中氮化物主要以铵态氮形式存在,说明铵态氮是导致稀土矿区土壤污染和水环境污染的主要原因;同时由于土壤的固氮作用、淋滤过程中铵态氮向下迁移及减少的共同作用,致使试验中原矿土壤和一般土壤铵态氮含量总体随天数表现为降低、升高、再降低趋势;并且与一般土壤相比,原矿土壤中稀土离子和NH~+_4会发生交换解析作用增加原矿土壤的固氮作用,同时稀土的存在会增加土壤本身对氮化物的吸附能力。研究结论为赣南离子型稀土矿浸矿过程中氮化物的迁移规律提供基础依据。     

涩感物质及涩感转导机制

涩感物质是影响食品及饮料风味品质的重要因素,由于涩感物质具有抗菌、抗癌、抗氧化、保护神经等作用,近年来成为人们研究的热点。通常涩感被描述为多酚等物质作用于口腔后产生的一种干燥、粗糙、褶皱和收敛的感觉,人们对涩感究竟是味觉,是触觉还是类似于辣感的三叉神经觉的争论一直存在。大多数关于涩感产生机制的研究都以蛋白质聚集沉淀的理论模型为基础。本文将对一些产生涩感的物质及涩感转导机制进行介绍。     

Research Progress on the Continuous Cropping Obstacles of Ginseng from Soil Improvement北大核心CSCD

The unique black soil resources and natural environment of Jilin province provide the proper conditions for the growth of ginseng-the king of herb. Ginseng industry has effectively promoted the development of medical and health industry，and brought considerable economic income for ginseng farmers. However，long-term continuous cropping of ginseng causes the chemical，biological，and physical properties deterioration of soil，which influences the yield and the quanlity of ginseng，and results in the occurrence of replant obstacle. Identifying the malignant soil factors in continuous cropping obstacles，then analyzing the evolution process，and putting forward the improvement strategies is the primary task of ginseng research at present. This paper reviews the influence of ginseng cultivation on the physicochemical property，nutrient， enzyme activity，microecology and ecotoxicity of the soil，and the achievements of improving ginseng soil by chemical and biological techniques and methods in recent 10 years. © 2022, Science Press (China). All rights reserved.     

Phenolics and plant allelopathy

Phenolic compounds arise from the shikimic and acetic acid (polyketide) metabolic pathways in plants. They are but one category of the many secondary metabolites implicated in plant allelopathy. Phenolic allelochemicals have been observed in both natural and managed ecosystems, where they cause a number of ecological and economic problems, such as declines in crop yield due to soil sickness, regeneration failure of natural forests, and replanting problems in orchards. Phenolic allelochemical structures and modes of action are diverse and may offer potential lead compounds for the development of future herbicides or pesticides. This article reviews allelopathic effects, analysis methods, and allelopathic mechanisms underlying the activity of plant phenolic compounds. Additionally, the currently debated topic in plant allelopathy of whether catechin and 8-hydroxyquinoline play an important role in Centaurea maculata and Centaurea diffusa invasion success is discussed. Overall, the main purpose of this review is to highlight the allelopacthic potential of phenolic compounds to provide us with methods to solve various ecology problems, especially in regard to the sustainable development of agriculture, forestry, nature resources and environment conservation.     

Analysis of benzoxazinone derivatives in plant tissues and their degradation products in agricultural soils

Plant allelopathy may be considered an additional means of weed control in modern agriculture, but its means of action are not well understood and knowledge of specific allelochemicals involved in allelopathy is required.Benzoxazinoids are a chemical family with the most active allelopathic compounds in some crops (e.g., wheat, rye or maize). The analysis of these analytes has been based mainly on gas chromatography coupled to mass spectrometry (MS) and liquid chromatography (LC) coupled to ultraviolet detection. To improve the sensitivity and selectivity, new methodologies (e.g., LC coupled to MS and tandem MS) are being developed. Less information is available on the analytical strategies to determine their degradation products in soil samples.This article presents an overview of recent advanced analysis of benzoxazinone derivatives in plant tissues and their degradation products in agricultural soils.     

Simultaneous determination of phenolic acids and 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one in wheat (Triticum aestivum L.) by gas chromatography-tandem mass spectrometry

A procedure using gas chromatography and tandem mass spectrometry (GC-MS-MS) has been developed for the identification and quantification of some allelochemicals in wheat (Triticum aestivum L.). The quantities of allelochemicals in wheat shoots ranged from 2.9 to 110 mg per kilogram of dry shoot residues. Compared with gas chromatography-mass spectrometry (GC-MS), the GC-MS-MS technique significantly increased instrument selectivity and sensitivity, thereby providing more reliable quantitation results in the determination of the phytotoxic compounds examined during this allelopathy research.     

Symbiotic signaling in actinorhizal symbioses

Actinorhizal symbioses are mutualistic associations between plants belonging to eight angiosperm families and soil bacteria of the genus Frankia. These interactions lead to the formation of new root organs, actinorhizal nodules, where the bacteria are hosted and fix atmospheric nitrogen thus providing the plant with an almost unlimited source of nitrogen for its nutrition. It involves an elaborate signaling between both partners of the symbiosis. In recent years, our knowledge of this signaling pathway has increased tremendously thanks to a series of technical breakthroughs including the sequencing of three Frankia genomes [1] and the implementation of RNA silencing technology for two actinorhizal species. In this review, we describe all these recent advances, current researches on symbiotic signaling in actinorhizal symbioses and give some potential future research directions.     

Determination of 18 phenolic acids in tobacco and rhizosphere soil by ultra high performance liquid chromatography combined with triple quadrupole mass spectrometry

An ultra high performance liquid chromatography with triple quadrupole mass spectrometry method for the determination of free and bound phenolic acids in tobacco plant and soil was developed. A simple solid‐phase extraction, which used Polar Enhanced Polymer column as stationary phase and methanol as mobile phase, was used for the clean‐up of bound phenolic acids, and a liquid‐phase extraction using chloroform as solvent was used to purify free phenolic acids. With our method, 18 phenolic acids in rhizosphere soil of continuous cropping flue‐cured cultivar k326 were separated and determined within 6 min with recoveries of 82–107% and relative standard deviations (n = 5) of 1.1–4.8%. Results showed that free phenolic acids accounted for 0–9, 92–100, and 69–100% of total phenolic acids in rhizosphere soil, cultivar k326 roots and leaves, respectively. Results also revealed that p‐hydroxybenzoic acid, p‐coumaric acid, vanillic acid, ferulic acid, and syringic acid were the predominant phenolic acids in rhizosphere soil of cultivar k326, and continuous cropping of cultivar k326 in the same farmland could lead to the accumulation of these phenolic acids in soil except syringic acid. The determination of phenolic acids provided detailed information for evaluating their source and characteristics in continuous cropping tobacco plant and soil.     

近红外光谱技术定量分析连作滁菊土壤中的阿魏酸含量

应用近红外光谱(NIRS)技术定量分析连作滁菊土壤样品中阿魏酸的含量.通过标准杠杆值、学生残差和马氏距离判断异常光谱,经二阶导数和Norris平滑滤噪预处理后,在6000~4000 cm-1范围,最佳因子数为7,采用偏最小二乘法(PLS)构建数学模型.结果表明,模型校正集和验证集与高效液相色谱仪(HPLC)测定的参考值之间均呈现良好相关关系,校正相关系数Rc为0.9914,交叉验证相关系数Rcv为0.9935,校正集误差均方根(RMSEC)为0.484,预测误差均方根(RMSEP)为0.539,交叉验证误差均方根(RMSECV)为0.615.研究结果表明,NIRS分析技术能够实现连作土壤中阿魏酸的快速检测,结果准确可靠.     

Identification of the roselle root rot pathogen and its sensitivity to different fungicides

Root rot is the main disease affecting roselle plantings and production and can seriously affect the yield and quality of calyces. Thus, it is urgent to identify the pathogen causing roselle root rot and screen effective pesticides to control the disease. In the present study, morphological observation, pathogenicity assays and molecular biology methods were used to identify the pathogen causing roselle root rot in Nanning, Guangxi Province, and four biological and four chemical fungicides were evaluated for their effects on the mycelial growth rate of the pathogen. The results showed that the pathogen causing roselle root rot in Nanning, Guangxi, was Fusarium solani, marking the first report of this fungus causing root rot of roselle in China. The fungicidal activity screening revealed differences in the inhibitory effects of the eight fungicides on the colony growth of F. solani. For the biofungicides, Bacillus amyloliquefaciens exhibited the best fungistatic effect, with an IC₅₀ of 1.10 mg/mL. When the mass concentration was 2.5 mg/mL, the mycelial growth of the pathogen was 100% inhibited, while Bacillus subtilis had the worst inhibitory effect, with an IC₅₀ of 46.78 mg/mL. When its mass concentration was 80 mg/mL, mycelial growth was only inhibited by 74.67%. For the chemical fungicides, carbendazim and thiophanate-methyl presented the strongest effects on F. solani, with IC₅₀ values of 0.0082 mg/mL and 0.0243 mg/mL, respectively. When the mass concentrations were 0.03 mg/mL and 0.075 mg/mL, mycelial growth was inhibited by 100%. These results provide a scientific basis for rationally selecting fungicides to control roselle root rot in field production.     

Thermal stability of soil organic matter was affected by 23-yr maize and soybean continuous cultivation in northeast of China

Long-term continuous cropping affects the biochemical quality of soil organic matter (SOM), but whether the effects are relevant with their thermal stability is less clear. In northeast China, long-term continuous cropping occurred frequently owing to higher yield and economic interest requirement. To verify the thermal stability properties of SOM affected by the long-term continuous cropping, the study focused on 23-yr continuous cultivated maize and soybean plots, where the effect of cropping is likely to be detected. Bulk soils sampled in 1991 and 2014 were studied by thermogravimetry and differential scanning calorimetry (DSC). The results showed typical bimodal peaks in DSC curve in bulk Mollisols. A labile fraction peak was observed at 354–366 °C low-temperature zone and recalcitrant fraction one at high temperature of 430–438 °C. Energy density (J mg^?1 OM) was greater in soybean plots compared to maize plots; in contrast, long-term continuous maize cultivation also increased energy density, in reverse in soybean plots after 23-yr cultivation. The DSC-T₅₀, temperature at which half of energy release occurred, typically showed larger responses to long-term cultivation than crop species. Results obtained support the hypothesis of a potential link between long-term continuous cropping and the thermal stability of SOM, and a correlation with crop species.