首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 29 毫秒
1.
Rate constants for the reaction of hydroxyl radicals with methyl bromide have been measured by the discharge flow—resonance fluorescence(DF—RF)technique over the temperature range 288—351K.The derived Arrbenius equation is:k”=(3.42±0.12)×10-12 exp(-(1419±158)/T)cm3/(mol·s).The tropospheric lifetime of methyl bromide was estimated to be 1.60 years.An ODP value of 0.33 for methyl bromide was obtained.  相似文献   

2.
Heterogeneous reactions of nitrogen dioxide (NO2) on soils collected from Dalian (S1) and Changsha (S2) were investigated over the relative humidity (RH) range of 5%-80% and temperature range of 278-328 K using a horizontal coated-wall flow tube. The initial uptake coefficients of NO2 on S2 exhibited a decreasing trend from (10 ± 1.3) × 10-8 to (3.1 ± 0.5) × 10-8 with the relative humidity increasing from 5% to 80%. In the temperature effect studies, the initial uptake coefficients of S1 and S2 decreased from (10 ± 1.2) × 10-8 to (3.8 ± 0.5) × 10-8 and from (16 ± 2.2) × 10-8 to (3.8 ± 0.4) × 10-8 when temperature increased from 278 to 288 K for S1 and from 278 to 308 K for S2, respectively. As the temperature continued to increase, the initial uptake coefficients of S1 and S2 returned to (7.9 ± 1.1) × 10-8 and (20 ± 3.1) × 10-8 at 313 and 328 K, respectively. This study shows that relative humidity could influence the uptake kinetics of NO2 on soil and temperature would impact the heterogeneous chemistry of NO2.  相似文献   

3.
河北农居环境颗粒态汞污染特征及健康评估研究   总被引:2,自引:1,他引:1  
赵亚娟  龚巍巍  栾胜基 《环境科学》2012,33(9):2960-2966
近年来,我国农村环境问题日渐加重,大气颗粒态汞对人体健康的危害逐渐凸现出来,而已有研究对我国农居环境中的汞污染状况关注较少. 以颗粒态汞为研究对象,于2009年7、8月及2010年10~12月,对河北省6个村庄中的34个典型农居环境进行PM10和PM2.5膜采样,采用冷原子荧光法测定颗粒态汞质量浓度. 结果表明,同一季节时,厨房PM10中汞质量浓度约是庭院PM10中汞质量浓度的2倍; 在同一空间内,PM10中汞质量浓度大小依次是冬季(3.004 ng·m-3)>秋季(1.550 ng·m-3)>夏季(1.127 ng·m-3); 同一季节时,PM2.5中汞质量浓度大小依次是厨房(0.795 ng·m-3±0.337 ng·m-3)>客厅(0.398 ng·m-3±0.159 ng·m-3)>庭院(0.321 ng·m-3±0.143 ng·m-3); PM2.5中的汞质量浓度占PM10中汞质量浓度的百分比为(52.4±13.5)%. 对农居环境PM2.5中汞的健康风险度水平进行评价,不同人群中儿童的暴露水平最高,其年均超额危险度<10-8. 可知农居环境PM2.5中汞对农户的健康风险在可以忽略的水平.  相似文献   

4.
北京大气PM10中水溶性氯盐的观测研究   总被引:10,自引:5,他引:5  
氯盐是大气气溶胶中重要水溶性无机盐,对2004年全年北京大气可吸入颗粒中氯盐的变化进行了监测,结果表明北京大气中可溶性氯盐的年均值在(3.1±1.7)μg·m-3,采暖期平均浓度为(4.6±2.1)μg·m-3,非采暖期平均浓度为(2.6±1.6)μg·m-3.最低值出现在5月,为(1.3±0.8)μg·m-3;最高值出现在12月,为(5.8±5.3)μg·m-3.日变化在秋冬季多为白天浓度低,晚上浓度高,夏春季多呈现上午高,下午低的特征;季节变化呈现秋冬季高,春夏季低的特点.  相似文献   

5.
上海市城区VOCs的年变化特征及其关键活性组分   总被引:39,自引:5,他引:34  
2010年在上海市城区开展了为期一年的连续观测,采用自动在线GC-FID方法定量测试了大气中56个VOCs物种的浓度.结果发现,上海市城区大气VOCs的全年小时体积分数为(2.47~301.48)×10-9,平均体积分数为(26.45±23.36)×10-9,其中,烷烃占46.72%,芳香烃占33.18%,烯烃占11.33%,乙炔占8.76%.T/B(甲苯/苯)为3.51±2.40,表明气团除受机动车影响外,受溶剂、油气和LPG挥发等其他VOCs排放的影响也比较突出;E/E(乙烷/乙炔)为0.98±0.68,表明气团存在老化现象,且春冬季节气团光化学年龄相对较短,夏秋季节光化学年龄相对较长.VOCs的浓度水平和组成在不同风向风速影响下存在一定差异,西南部石化和化工企业排放的VOCs对城区的影响明显,其主要物种为芳香烃和烯烃;该地区气团的OH消耗速率常数(KOH)为8.05×10-12 cm3·分子-1·s-1,平均VOCs最大O3增量反应活性(4.00 mol·mol-1)与乙烯相当,平均反应活性较强;对OH消耗速率(LOH)贡献率最大的是烯烃(42.21%)和芳香烃(40.83%),对臭氧生成潜势(OFP)贡献率最大的是芳香烃(62.75%)和烯烃(21.70%),VOCs的关键活性组分是二甲苯、甲苯、乙苯、乙烯、丙烯、反-2-丁烯及异戊二烯.  相似文献   

6.
Atmospheric volatile organic compounds (VOCs) were observed by an on-line gas chromatography-flame ionization detector monitoring system from November 2016 to August 2017 in Beijing. The average concentrations were winter (40.27 ± 25.25 μg/m3) > autumn (34.25 ± 19.90 µg/m3) > summer (32.53 ± 17.39 µg/m3) > spring (24.72 ± 17.22 µg/m3). Although benzene (15.70%), propane (11.02%), ethane (9.32%) and n-butane (6.77%) were the most abundant species, ethylene (14.07%) and propene (11.20%) were the key reactive species to ozone formation potential (OFP), and benzene, toluene, ethylbenzene, m-xylene + p-xylene and o-xylene (54.13%) were the most reactive species to secondary organic aerosol formation potential (SOAFP). The diurnal and seasonal variations indicated that diesel vehicle emission during early morning, gasoline vehicle emission at the traffic rush hours and coal burning during the heating period might be important sources. Five major sources were further identified by positive matrix factorization (PMF). The vehicle exhaust (gasoline exhaust and diesel exhaust) was found to be contributed most to atmospheric VOCs, with 43.59%, 41.91%, 50.45% and 43.91%, respectively in spring, summer, autumn and winter; while solvent usage contributed least, with 11.10%, 7.13%, 14.00% and 19.87%, respectively. Biogenic emission sources (13.11%) were only identified in summer. However, both vehicle exhaust and solvent usage were identified to be the key sources considering contributions to the OFP and SOAFP. Besides, the contributions of combustion during heating period and gasoline evaporation source during warm seasons to OFP and SOAFP should not be overlooked.  相似文献   

7.
北京市室外空气真菌分布特征   总被引:9,自引:1,他引:8  
通过定点取样研究北京市空气真菌的种类组成,浓度特征及其动态变化规律.监测结果表明,北京市空气真菌平均浓度为(1164.8±73.2)CFU.m-3,浓度变异很大,变化范围为23.6~13959.5CFU.m-3.空气中优势真菌为枝孢属(Cladosporium)、青霉属(Penicillium)、链格孢属(Alternaria)、曲霉属(Aspergillus)和无孢菌(non-sporing),其中枝孢属是绝对优势真菌,浓度约占真菌总浓度的1/3以上.文教区和公园绿地空气真菌浓度夏季和秋季较高,春季和秋季较低,而交通干线空气真菌浓度4季变化趋势不明显.文教区和公园绿地空气真菌浓度明显高于交通干线(p<0.05),文教区和公园绿地之间则没有显著差异.  相似文献   

8.
This study encompassed the regular observation of nine polycyclic aromatic hydrocarbons (PAHs) and three nitro-PAHs (NPAHs) in particulate matter (PM) in Shanghai in summer and winter from 2010 to 2018. The results showed that the mean concentrations of ?PAHs in summer decreased by 24.7% in 2013 and 18.1% in 2017 but increased by 10.2% in 2015 compared to the data in 2010. However, the mean concentrations of ?PAHs in winter decreased by 39.7% from 2010 (12.8 ± 4.55 ng/m3) to 2018 (7.72 ± 3.33 ng/m3), and the mean concentrations of 1-nitropyrene in winter decreased by 79.0% from 2010 (42.3 ± 16.1 pg/m3) to 2018 (8.90 ± 2.09 pg/m3). Correlation analysis with meteorological conditions revealed that the PAH and NPAH concentrations were both influenced by ambient temperature. The diagnostic ratios of PAHs and factor analysis showed that they were mainly affected by traffic emissions with some coal and/or biomass combustion. The ratio of 2-nitrofluoranthene to 2-nitropyrene was near 10, which indicated that the OH radical-initiated reaction was the main pathway leading to their secondary formation. Moreover, backward trajectories revealed different air mass routes in each sampling period, indicating a high possibility of source effects from the northern area in winter in addition to local and surrounding influences. Meanwhile, the mean total benzo[a]pyrene-equivalent concentrations in Shanghai in winter decreased by 50.8% from 2010 (1860 ± 645 pg/m3) to 2018 (916 ± 363 pg/m3). These results indicated the positive effects of the various policies and regulations issued by Chinese authorities.  相似文献   

9.
太湖典型草、藻型湖区有色可溶性有机物的吸收及荧光特性   总被引:27,自引:6,他引:21  
2004年4月对太湖典型草、藻型湖区东太湖和梅梁湾有色可溶性有机物(CDOM)的吸收和荧光特性进行了研究.通过实验测定方法得到东太湖和梅梁湾CDOM的光谱吸收系数及其荧光值.结果表明,溶解性有机碳(DOC)的浓度在6.3~17.2 mg/L间变化,其均值为9.08±2.66 mg/L;CDOM在280 nm和355 nm的吸收系数分别为11.2~32.6 m-1(平均值17.46m-1±5.75 m-1)和2.4m~8.3 m-1(平均值4.17 m-1±1.47 m-1);355 nm波长处CDOM的比吸收系数为0.31~0.64 L·(mg·m)-1,平均值0.46L·(mg·m)-1±0.08 L·(mg·m)-1.355 nm的激发波长、450 nm的发射波长处的荧光值的变化范围0.50~3.91 nm-1(平均值1.32nm-1±0.84 nm-1).2类草、藻型湖区的DOC浓度、CDOM吸收系数、355 nm处荧光值均存在显著性差异,但CDOM比吸收系数和指数函数斜率则没有显著性差异,由此则反映了CDOM来源的一致性.CDOM的吸收系数与DOC浓度的相关性随波长的降低而增加,在短波部分存在明显的正相关.355 nm处的荧光值、DOC浓度与CDOM吸收系数存在如下显著性的正相关关系:Fn(355)=0.544(±0.035)a(355)-0.946(±0.152),DOC=1.537(±0.196)a(355)+2.683(±0.862).280~500 nm、280~360 nm、360~440 nm指数函数斜率分别为14.37μm-1±0.73μm-1、19.17μm-1±0.84μm-1、13.38μm-1±0.82μm-1.  相似文献   

10.
机动车VOCs排放特征和排放因子的隧道测试研究   总被引:25,自引:3,他引:22  
为了得到真实道路交通状态下的城市机动车排放因子,选取广州珠江隧道,进行了机动车VOCs排放特征和排放因子的隧道实验.实验得到隧道机动车平均排放因子为(0.52±0.07)g·km-1·辆-1,其中轻型车排放因子为(0.32±0.14)g·km-1·辆-1,重型车排放因子为(0.26±0.33)g·km-1·辆-1,摩托车排放因子为(1.16±0.26)g·km-1·辆-1.机动车排放的VOCs中烷烃占39.7%,烯烃和炔烃占35.3%,芳香烃占25.0%.排放物质居前三位的排放因子分别为乙烯(52.9±7.4)mg·km-1·辆-1、异戊烷(41.5±7.0)mg·km-1·辆-1和甲苯(31.7±5.5)mg·km-1·辆-1.隧道实验得到的排放因子与机动车台架实验的结果基本吻合.  相似文献   

11.
This study aims to identify therelationship between the climatic variablesand yields of three crops (wheat (Triticum aestivum L.), maize (Zeamays L.) and cotton (Gossypiumhirsitum L.) in the Cukurova region ofTurkey. In the study, time series data wereused to analyse crop yields across variousclimate factors for the period 1975 to1999. The climatic variables were arrangedaccording to phonological periods of theexamined crops such as planting, floweringand harvesting time. A linear perturbationmodel (LPM) was used for the identificationof the role of climate variables. 27climatic factors were considered asexplanatory variables in the model. Astepwise selection method in the selectionand introduction of independent variableswas used for regression equation for wheat,maize and cotton. The results of the linearperturbation model (LPM) showed that theR2 values for wheat, maize and cottonwere found 46.1%, 57.2% and 74.5%,respectively. The highest variationcoefficient (CV) was found in maizeproduction (43.4%) followed by cotton(23.14%) and wheat (15.29%). The mostsignificant climatic factor affectingdeviations in crop yields is related intemperature at planting, flowering andharvesting time. It is suggested thatfarmers would be better off with theapplying adaptation measurements. Therefore, policy makers should focusefforts on reducing production risksproviding climatic information anddeveloping risk management institutions.  相似文献   

12.
Bénin, like other countries in sub-Saharan Africa, has initiated programs to reform agricultural input and output markets. While the impact of the reform programs has been different for each country, it is commonly observed that impact at the farm level has been less than anticipated. A central theme of this paper is to assess the impact of fertilizer market reforms on the fertilizer market structure and fertilizer use for both food and export (cotton) crop production in Bénin. This analysis of farm-level policy impact is based on data from 899 farm households randomly selected and interviewed in all six départements of Bénin in 1998/1999. Results of the study show that there have been only insignificant changes in the fertilizer market structure. Access to fertilizers has not improved; prices for fertilizer have risen in real terms, resulting in application rates lower than that recommended by extension agents. The effects of the reform programs are vital for investment decisions and provide lessons for introducing alternative approaches for improving soil fertility or management. Since 1992, 54% of farmers find maize (Zea mays L.) production more profitable, while 38% reported that cotton (Gossypium hirsutum L.) production has become more profitable. As a result of the mixed effects of the fertilizer market reform program on the level of fertilizer use and profitability, there is need to develop efficient soil fertility management strategies for small-scale farmers. Such strategies should incorporate the use of complementary inputs, such as seeds with a high level of response to the balanced nutrient package.  相似文献   

13.
Nectar is secreted in particular rhythms throughout the lifespan of a flower, which allows determining the nectar production dynamics. This paper compares nectar features in Mucuna japira and Mucuna urens describing: dynamics of nectar production, floral response to nectar removal, resorption, nectar sugar composition, and variation in nectar sugar composition. M. japira inflorescence bears 12–21 yellow flowers, which are in anthesis for 7 days, whereas M. urens inflorescence bears 36–54 greenish flowers, but only 1–3 flowers are in anthesis simultaneously that last one night. Nectar volume and sugar concentration were measured, and the amount of sugar was estimated. Qualitative and quantitative nectar sugar composition was determined. Both species had a constant nectar sugar concentration (ca. 10% for M. japira and ca. 16% for M. urens) and secreted high volumes of nectar (ca. 340 μl per flower for M. japira and 310 μl per flower for M. urens), during 5 days for M. japira and 6 h for M. urens, but after the first removal, i.e., when flower opening mechanism is triggered, nectar production stops immediately. Nectar resorption occurred in both species. Nectar sugar composition showed some similarities between the species. Variation in nectar sugar composition occurred in both species. The Mucuna species are dependent on their pollinators to produce fruits and seeds, and they have different strategies to promote the necessary interaction with birds or bats, especially related to nectar and flower characteristics.  相似文献   

14.
厌氧氨氧化微生物颗粒化及其脱氮性能的研究   总被引:22,自引:4,他引:18  
利用厌氧颗粒污泥作为种泥,启动SBR反应器,旨在培养厌氧氨氧化颗粒污泥以及研究其脱氮性能.结果表明,水力停留时间(HRT)是富集厌氧氨氧化微生物的1个重要控制因素,以HRT为30 d,第58 d时,SBR反应器就出现厌氧氨氧化现象,与此同时,颗粒污泥由灰黑色变为棕褐色,粒径减小.到第90 d时,成功培养出厌氧氨氧化颗粒污泥,NH+4-N和NO-2-N同时被去除,最大去除速率分别达到14.6 g/(m3·d)和6.67 g/(m3·d).从第110 d开始,逐步降低HRT,以提高基质负荷促进厌氧氨氧化菌生长.到目前t=156 d,HRT降到5 d,氨氮和亚硝酸氮的去除率分别达到60.6%和62.5%,亚硝酸氮/氨氮的比率为1.12.污泥也由棕褐色变为红棕色,形成红棕色的具有高厌氧氨氧化活性颗粒污泥,总氮负荷达到34.3 g/(m3·d).  相似文献   

15.
溶解性有机质强化棉花修复镉污染土壤   总被引:2,自引:2,他引:0  
闵涛  罗彤  陈丽丽  茹思博  李俊华 《环境科学》2022,43(3):1577-1583
为探究溶解性有机质(DOM)对棉花修复镉(Cd)污染土壤的影响,通过盆栽试验研究棉花秸秆溶解性有机质(CM)和农家肥溶解性有机质(FM)在3种外源Cd(mg·kg-1)添加含量为0(C0)、5(C5)和10(C10)下对土壤有效态Cd含量、棉花生物量、光合作用参数和Cd积累的影响.结果表明,CM和FM施入能提高土壤有效...  相似文献   

16.
Degradation kinetics of microencapsulated chlorpyrifos (CPF-MC) in soil and its influence on soil microbial community structures were investigated by comparing with emulsifiable concentration of chlorpyrifos (CPF-EC) in laboratory. The residual periods of CPF-MC with fortification levels of 5 and 20 mg/kg reached 120 days in soil, both of the degradation curves did not fit the first-order model, and out-capsule residues of chlorpyrifos in soil were maintained at 1.76 (±0.33) and 5.92 (±1.20) mg/kg in the period between 15 and 60 days, respectively. The degradation kinetics of CPF-EC fit the first-order model, and the residual periods of 5 and 20 mg/kg treatments were 60 days. Bacterial community structures in soil treated with two concentrations of CPF-MC showed similarity to those of the control during the test period, as seen in the band number and relative intensities of the individual band on DGGE gels (p 〉 0.05). Fungal community structures were slightly affected in the 5 mg/kg treatments and returned to the control levels after 30 days, but initially differed significantly from control in the 20 mg/kg treatments (p 〈 0.05) and did not recover to control levels until 90 days later. The CPF-EC significantly altered microbial community structures (p 〈 0.05) and effects did not disappear until 240 days later. The results indicated that the microcapsule technology prolonged the residue periods of chlorpyrifos in soil whereas it decreased its side-effects on soil microbes as compared with the emulsifiable concentration formulation.  相似文献   

17.
Reducing fertiliser applications can reduce production costs for cotton (Gossypium hirsutum L.) growers, as well as nitrogen (N) leaching into the soil and contamination of surface and ground water. But altered N fertilisation may also affect pests and their natural enemies. In this study, plots with four different levels of fertiliser input (0, 45, 90 and 135 kg ha−1 N) were used to investigate the influence of N on cotton pest and beneficial arthropod populations, and on cotton yield in Tifton, GA, USA. We predicted that (1) N fertilisation will correlate positively with cotton plant growth; (2) increased N fertilisation will increase pest populations because plants with more N will be more nutritious for and attractive to herbivores; (3) populations of beneficial arthropods and predation of pests will decline with increased N fertilisation because of reduced plant signaling; (4) increased N fertilisation will increase pest mortality due to parasitoids because of increased host quality. Cotton plant growth was enhanced by N fertilisation but yield was unaffected. N fertilisation significantly affected some pest arthropods but inconsistently. Mirids were most abundant in the high N treatment in 1 year of the study and cotton aphids were most abundant in the highest N treatment in the other year of the study. Arthropod predators were generally more abundant in the high N treatment but only spiders and Geocoris spp. were significantly affected by N treatment, with highest numbers present in the highest N treatment but the significant differences were each only in a single year. The greatest mortality of sentinel pest eggs (Spodoptera exigua) due to predation occurred under low N conditions. N fertilisation had no significant effects on parasitism of feral or sentinel caterpillars.  相似文献   

18.
Long distance dispersal may have important consequences for gene flow and community structure. The dispersal of many plants depends on transport by vertebrate seed dispersers. The shapes of seed shadows produced by vertebrates depend both on movement patterns of the dispersers and on the dynamics and effects of passage through the disperser’s gut (i.e. the retention time, survival and germination of ingested seeds). A combination of experiments with captive waterbirds and aquatic plant seeds was used to analyse the following: (a) the effects of inter- and intra-specific variation in seed size and duck species on seed retention time in the gut and (b) the relationship between retention time and the percent germination and germination rates of seeds. Among the three Scirpus species used, those with smaller seeds showed higher survival after ingestion by birds and longer retention times inside their guts than those with larger seeds. For Potamogeton pectinatus, only seeds from the smaller size class (<8 mg) survived ingestion. Retention time affected the percent germination and germination rate of Scirpus seeds but in a manner that varied for the different plant and bird species studied. We recorded both linear and non-linear effects of retention time on percent germination. In addition, germination rate was positively correlated with retention time in Scirpus litoralis but negatively correlated in Scirpus lacustris. Small seed size can favour dispersal over larger distances. However, the effects of retention time on percent germination can modify the seed shadows produced by birds due to higher percent germination of seeds retained for short or intermediate periods. The changes in dispersal quality associated with dispersal distance (which is expected to be positively related to retention time) will affect the probability of seedling establishment over longer distances and, thus, the spatial characteristics of the effective seed shadow.  相似文献   

19.
恩诺沙星是医药及水产养殖业广泛使用的喹诺酮类抗生素,是我国地表水中残留量较多的抗生素种类之一;然而有关该抗生素对水体中浮游植物毒理作用以及后者对其去除作用的研究还鲜见报道.本研究以绿藻门的胶网藻(Dictyosphaerium sp.)为对象,通过12 d室内培养实验,分析在不同浓度(0、 5、 25、 50和100 mg·L~(-1))恩诺沙星暴露的条件下,胶网藻的生长、光合作用活力和胞外多糖的响应变化及其对不同浓度恩诺沙星的去除效率.结果表明,各处理组中胶网藻的生物量和光合色素含量均随培养时间的增加而升高,但与对照组相比,恩诺沙星对胶网藻的生长和光合色素积累均产生显著抑制作用(P0.01).通过拟合分析,计算出恩诺沙星对胶网藻96 h半数致死浓度(LC_(50))为(241.29±7.33) mg·L~(-1),表明胶网藻能够适应高浓度的恩诺沙星胁迫.同时发现,当恩诺沙星浓度5 mg·L~(-1)时,能够促进胶网藻的最大光合速率(F_v/F_m),但浓度5 mg·L~(-1)时则对胶网藻具有抑制作用(P0.01);实际光合速率(Yeild)和最大电子传递速率(ETR_(max))在12 d内呈现先降后升的变化趋势,胶网藻在6 d后可逐渐适应胁迫环境而恢复一定的光合活力.此外,恩诺沙星可刺激胶网藻释放胞外多糖,水溶性多糖(RPS)和胞外胶鞘多糖(CPS)含量均随恩诺沙星浓度升高而增加.实验结束时, 4个无藻对照组(5、 25、 50和100 mg·L~(-1))中恩诺沙星的去除率分别为7.27%、 5.56%、 5.30%和4.88%,而添加胶网藻的处理组其去除率分别为对照组的3.21、 3.01、 2.69和2.83倍,表明胶网藻对于恩诺沙星的去除具有显著的促进作用(P0.01).本研究结果为理解喹诺酮类抗生素对水体初级生产者的生态毒性提供了新资料,同时也为水体抗生素残留的生态去除和淡水微藻的生物资源化利用提供了新的思路.  相似文献   

20.
Aqueous extracts from various plant parts of fenugreek (3%) (aerial parts: leaves and stems (LS), roots (R), ground seeds (GS) and not ground seeds (NGS)) and petroleum ether, ethyl acetate and methanolic fractions of the aerial parts were assayed to determine their antifungal potential against Botrytis cinerea, Fusarium graminearum, Alternaria sp., Pythium aphanidermatum, and Rhizoctinia solani. All fenugreek plant parts showed antifungal potential and the magnitude of their inhibitory e ects was species and plant parts dependent. R extract was shown less toxic (30.38%), whereas NGS extract expressed the strongest inhibition, with an average of 71.44%, followed by GS (58.56%) and LS (57.1%). Screening indicated that P. aphanidermatum was the most resistant species, with an average inhibition of 34.5%. F. graminearum, Alternaria sp. and R. solani were the most sensitive species, and were similarly inhibited (63.5%). The stability test indicated that the aqueous extracts of all plant parts lost approximately 50% of their relative activity after one month of storage at 4°C, whilst they lost 60%–90% of their activity when stored at ambient temperature for one month. The antifungal activity resided mainly in the methanol fraction and the minimum inhibitory concentration (MIC) of methanol fraction witch caused total inhibition of R. solani and Alternaria sp. was 60 g/ml. Results of current study suggested that the constituents of Trigonella foenum-graecum have potential against harmful pathogenic fungi. Therefore, fenugreek could be an important source of biologically active compounds useful for developing better new antifungal drugs.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号