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1.
廊道式人工湿地处理污水过程中氨氮的去除效果研究 总被引：2，自引：0，他引：2
通过廊道式人工湿地(CCW)的生产性试验工程,研究了该处理系统的性能及系统内部氨氮的变化规律.结果表明,CCW处理系统的去除效率高且稳定,氨氮的去除率平均为88%,质量去除率平均为(6.94±2.07)gN·m-2·d-1,系统内部第三单元的氨氮质量去除率最高;CCW处理系统的氨氮质量负荷率小于10gN·m-2·d-1时,质量去除率与质量负荷率呈明显的线性相关,质量负荷率大于等于20gN·m-2·d-1时,进水浓度和出水浓度之间呈明显线性相关;处理系统各处理单元及系统整体的体积去除率常数(Kv值)均大于其他湿地处理系统;CCW处理系统氨氮浓度变化与pH值的变化趋势并不一致. 相似文献
2.
低温等离子体发生器工作参数优化 总被引：4，自引：4，他引：0
低温等离子体（non-thermal plasma,NTP）发生器放电产生的活性物质可有效去除柴油机颗粒捕集器（diesel particular filter,DPF）中沉积的颗粒物（particulate matter,PM）,而发生器的工作参数直接影响活性物质的浓度,选取合适的工作参数有利于活性物质的产生。该文以空气为气源,考察了放电区表面温度、放电电压、放电频率、空气流量4个因素对NTP发生器产生活性物质浓度的影响。以O3质量浓度作为试验指标,进行了正交试验设计,并对试验结果进行单因素影响规律的分析、极差分析以及方差分析。研究表明：较低的放电区表面温度和放电频率有利于O3的生成,O3质量浓度随着空气流量的增大先升高后降低,随放电电压的变化没有明显的增减趋势;放电区表面温度、空气流量为显著因素,放电电压和放电频率为不显著因素;各因素对试验结果影响的大小顺序为：空气流量＞放电区表面温度＞放电频率＞放电电压;NTP反应器产生活性物质的较优组合是：放电区表面温度40℃、放电电压19 kV、放电频率7 kHz、空气流量5 L/min。研究结果对开发用于分解柴油机PM的NTP系统、优化NTP技术再生DPF的研究有重要的指导意义。 相似文献
3.
为研究接触辉光放电等离子体（CGDP）对茄病镰刀菌（Fusarium solani）的杀菌作用及机制,本试验以Fusarium solani为试材,考察CGDP处理过程中电压、处理时间、抗坏血酸浓度、孢子初始浓度等因素对杀菌效果的影响;并对Fusarium solani生长、孢子形态、细胞膜完整性及过程中所产生的活性粒子进行分析。通过Linear、Weibull和Log-Logistic 3种数学模型分析不同电压下CGDP杀菌动力学特性,以相关系数（R2）、精确因子（Af）、偏差因子（Bf）和均方根方差（RMSE）4个参数评价拟合效果。结果表明,CGDP对Fusarium solani孢子有着明显的杀菌效果;升高电压、延长处理时间、降低抗坏血酸浓度和孢子初始浓度均能有效抑制孢子生长,使杀菌效率提高（P<0.05）;CGDP处理30 min,活性物质（·OH、H2O2、NO3-）浓度分别增加至1.57 mg·L-1、73.89 mmol·L-1和12.72 mg·L-1,pH值由7.07降至4.66;孢内核酸和蛋白质的渗漏量以及PI染色和扫描电镜结果表明,CGDP对Fusarium... 相似文献
4.
浙江奉化市池塘的底泥经过反复培养、驯化,从中筛选、分离出反硝化细菌,在模拟实验条件下,研究其对不同浓度的硝酸盐氮和亚硝酸盐氮的去除情况,讨论反硝化菌种的生长情况。结果表明,在初始浓度为1、25、50mg·L^-1的硝酸盐氮和亚硝酸盐氮模拟池塘中,随着实验的进行,对污染物的去除效果逐渐提高。其中在1mg·L^-1的浓度组中,3d内硝酸盐氮和亚硝酸盐氮去除率就分别达到了95．8％和90．2％;在25mg·L^-1的浓度组中,第6d硝酸盐氮和亚硝酸盐的去除率分别为93．8％和87．8％;在50mg·L^-1的浓度组中,第6d硝酸盐氮和亚硝酸盐的去除率分别为89．7％和78．7％。此外,反硝化菌对硝酸盐氮的去除效果略优于亚硝酸盐氮,而且硝酸盐氮和亚硝酸盐氮的浓度越低,对其去除效果越好,达到稳定状态的时间越短。在模拟池塘中,菌种的生长情况与硝酸盐氮和亚硝酸盐氮的浓度呈负相关,即污染物的浓度越高反硝化菌的生长情况越差。对反硝化菌的生态影响因子研究表明,其反硝化最适宜的pH值为6～7,温度为25～35℃;而且在同一pH值和温度条件下,硝酸盐氮和亚硝酸盐氮浓度越低,反硝化菌对其去除效果越好。 相似文献
5.
凤眼莲对不同程度富营养化水体氮磷的去除贡献研究 总被引：14，自引：0，他引：14
采用人工模拟方法,研究了凤眼莲在不同程度富营养化水体中对N、P的吸收和去除作用。结果表明,凤眼莲在总氮(TN)、总磷(TP)初始浓度分别为2.06～20.08mg·L-1和0.14～1.43mg·L-1的4种富营养化水体中均可正常生长,近1年的试验中,凤眼莲总生物量累计增加41.03～47.12kg·m-2,平均生物量增长率为0.096～0.262kg·m-2·d-1。凤眼莲地上部N和P平均含量分别为24.16～34.15mg·g-1和3.46～6.90mg·g-1;地下部N和P平均含量分别为11.76～18.45mg·g-1和6.02～8.50mg·g-1。凤眼莲在4种富营养化水体中的N和P吸收量累计分别为43.06～71.16g·m-2和8.68～16.63g·m-2,且随水体初始N、P浓度的升高而增加,并与自身生物量呈极显著正相关(P0.01)。在N、P负荷较低的水体(Ⅰ和Ⅱ)中,凤眼莲吸收对N、P的去除贡献均超过100%,表明凤眼莲吸收利用了底泥中部分N和P;而在N、P负荷较高的水体(Ⅲ和Ⅳ)中,凤眼莲吸收对N、P的去除贡献也均超过42.32%和83.79%。因此,本试验条件下凤眼莲吸收在水体N、P去除中起主要作用。 相似文献
6.
牛粪厌氧发酵酸化处理条件的优化 总被引：4，自引：0，他引：4
在牛粪厌氧发酵过程中,高含量的木质纤维素降低了厌氧发酵的水解酸化速度,水解酸化阶段成为牛粪厌氧发酵过程的限速步骤。为提高牛粪两相厌氧发酵甲烷的产量,对酸化处理条件进行优化。利用两相厌氧发酵工艺,在35℃发酵条件下,研究牛粪酸化处理时间、搅拌频率、料液浓度和尿素添加量对甲烷总产量的影响。单因素试验结果表明,最佳的酸化时间、搅拌频率、料液浓度、尿素添加量分别为96 h、3次.24 h 1(60 r·min-1,1 min·次-1)、8.0%、1.28 g·L-1。在单因素试验基础上,选取酸化时间、料液浓度、尿素添加量为自变量,以甲烷总产量为响应值,根据中心组合设计原理设计试验。采用3因素5水平的响应面分析法,建立酸化处理条件对甲烷产量影响的回归模型,进行显著性和交互作用分析。结果表明,在35℃、搅拌频率为3次.24 h 1(60 r·min-1,1 min·次-1)酸化条件下,酸化料液浓度对甲烷产量影响最大,尿素添加量次之,酸化时间影响最小;酸化最佳处理条件为:酸化时间93.7 h、料液浓度8.3%、尿素添加量1.26 g·L-1。经过优化,甲烷含量、总产气量、挥发性固体含量(VS)和化学需氧量(COD)去除率分别比未酸化处理提高了14.3%、44.7%、41.8%和33.9%,而酸化处理对纤维素、半纤维素和木质素含量影响不显著。由此可见,牛粪酸化处理有利于甲烷产生,可提高甲烷含量及VS和COD去除率。 相似文献
7.
为对比不同气源的介质阻挡放电型低温等离子体发生器的性能参数,分别以氧气和空气为气源,对发生器进行了静态对比试验,研究了放电电极面积、放电电压峰峰值、气体体积流量对放电功率、单周期电荷传输量、O_3浓度、O_3产量和O_3产率的影响。结果表明,当放电电极面积增大时,放电功率和单周期电荷传输量均线性增大,但空气源对应的放电功率和单周期电荷传输量及其增长速率较低;此时,氧气和空气源的O_3浓度整体呈上升趋势而O_3产率则呈下降趋势。当放电电压峰峰值增大时,氧气和空气源的放电功率和单周期电荷传输量均显著增大,且后期增大速率加快;O_3浓度均先升后降而O_3产率则逐渐减小,高浓度和高产率不可兼得。不同放电频率下,氧气源的最大臭氧浓度大于55 mg/L,空气源的最大臭氧质量浓度在4~8 mg/L之间。当气体体积流量增大时,氧气源的放电功率和单周期电荷传输量均先上升后趋于平缓,而空气源的放电功率和单周期电荷传输量则逐渐增大;氧气源的O_3浓度下降,O_3产量上升直至平缓,而空气源的O_3浓度则先增后减,O_3产量逐渐上升但上升速率放缓;氧气源和空气源的O_3产率均随气体体积流量的增大而缓慢上升。以氧气为气源时,气体体积流量不宜超过10 L/min;以空气为气源时,气体体积流量可选取为9 L/min左右。研究结果可为低温等离子体喷射系统优化及柴油机颗粒物捕集器的再生研究提供参考。 相似文献
8.
病死猪辅热好氧发酵尾气中的恶臭物质分析 总被引：2，自引：0，他引：2
为了明确病死猪辅热好氧发酵过程中产生的恶臭气体的种类及其排放规律,为控制恶臭气体排放浓度、降低病死猪无害化处理过程对环境的污染提供基础依据,该研究以病死猪为发酵原料,玉米秸秆为辅料,开展病死猪辅热好氧发酵试验,发酵过程中,采集处理槽排放的尾气,分析尾气中的有机恶臭物质组分并测定其排放浓度,同时测定其中的氨气浓度,并对不同发酵阶段尾气中气味活度值大于1的恶臭物质进行相关性分析和主成分分析。结果表明：在病死猪辅热好氧发酵过程中共检出36种恶臭物质,其中能准确定性与定量检测的有19种,包括3种含硫化合物,1种烷烃化合物,12种芳香烃化合物,1种酚类化合物,1种胺类化合物和1种无机气体;发酵全程或部分时间点超过其嗅阈值的有3-乙基甲苯、4-乙基甲苯、二甲基二硫醚、二甲基硫醚、氨气、对甲酚、甲硫醇、三甲胺8种,达到的最高浓度依次为0.241、0.350、0.247、0.280、69.06、0.041、0.314、0.033 mg/m3,与其嗅阈值的比值依次为2.745 7、8.634 7、29.325 6、36.981 5、66.669 1、173.314 5、374.77、432.471 1;各发酵阶段的主要致臭物质成分存在差异：在0～12 h的发酵阶段,三甲胺、甲硫醇、二甲基硫醚、二甲基二硫醚、氨气、对甲酚、3-乙基甲苯、4-乙基甲苯为主要致臭物质,在12～36 h的发酵阶段,三甲胺、甲硫醇、二甲基硫醚、二甲基二硫醚、氨气、对甲酚为主要致臭物质,在36～72 h的发酵阶段,三甲胺、甲硫醇、二甲基硫醚、二甲基二硫醚、氨气为主要致臭物质;不同发酵阶段的臭气强度存在较大波动：在0～72 h内的发酵过程中,0～3 h内臭气强度缓慢增强,但第6小时臭气强度有明显下降,在6～18 h时再次增强,第18小时臭气强度达到峰值,18～72 h内持续下降直至平稳。该研究可为病死猪辅热好氧发酵过程中恶臭物质的减控策略提供理论参考。 相似文献
9.
检测了健康肉鸡以不同剂量土霉素混饲给药后,在不同时间鸡粪中土霉素的含量变化,并比较避光及人工光照条件下灭菌鸡粪中土霉素的降解规律,以及在避光条件下灭菌、未灭菌及灭菌后加降解菌处理,鸡粪中土霉素的降解规律。结果表明,健康肉鸡混饲给予土霉素（100、200、400mg·kg-1）后,鸡粪中土霉素排泄量在给药后6～8h达到高峰,峰浓度分别为13.58、36.15mg·kg-1和50.73mg·kg-1,并于30、62h和72h时检测不到土霉素;对鸡粪中土霉素的浓度随时间变化趋势进行曲线拟合,发现各处理组的这种变化趋势均符合一级动力学方程Ct=C0e-kt。经灭菌鸡粪中土霉素的降解受光照条件和土霉素初始浓度的影响,初始浓度为10、20、40mg·kg-1时,避光条件下,土霉素降解半衰期分别为55.5、123.8d和173.3d;人工光照条件下,鸡粪中的土霉素降解较快,降解半衰期分别为14.8、21.1d和27.5d。此外,无论是在避光还是人工光照条件下,较高初始浓度组的土霉素降解速率均比较低初始浓度组慢。去除光照因素后,鸡粪中所含土霉素的降解主要受微生物及土霉素初始浓度的影响,初始浓度为10、20、40mg·kg-1时,灭菌组土霉素降解半衰期分别为78.7、103.4d和157.5d,未灭菌组为40.5、50.6d和97.6d,灭菌后加降解菌组为14.5、33.6d和51.3d,说明鸡粪中微生物的存在可加快土霉素的降解。相同处理条件下,土霉素的降解速率随药物初始浓度的升高而降低。 相似文献
10.
铁碳复合材料催化内电解技术处理模拟农村铅污染水体效果 总被引：1，自引：1，他引：0
为考察基于新型铁炭复合填料的催化内电解技术处理模拟农村铅污染水体的特性,该文采用单因素试验设计和八因素三水平(考虑交互作用)正交试验设计,研究了初始pH值(1.0~8.0)、反应时间(10~90 min)和曝气量(0~12 L/h)对Pb~(2+)去除效果的影响。结果表明:初始pH值从1.0升高到8.0,铅(Pb~(2+))去除率先缓慢上升后急剧降低;反应时间从10 min提高到60 min,Pb~(2+)去除率稳步上升,继续延长至90 min,去除率趋于稳定;曝气量从0增大到12 L/h,Pb2+去除率先快速增加后缓慢降低;3个因素对Pb~(2+)去除效果的显著影响大小依次为:曝气量初始p H反应时间,最佳反应条件是:初始p H值3.0、反应时间60 min、曝气量6 L/h。按照一级动力学模型对反应阶段进行拟合,采用电子扫描显微镜(scanning electron microscope,SEM)观察了反应前后铁炭填料表面形态和结构变化,并利用X射线衍射(X-ray diffraction,XRD)分析了反应后溶液组分,推断得出催化内电解去除铅的机理是氧化还原和化学沉淀。当初始Pb~(2+)浓度为1.0 mg/L,在最佳试验条件下,处理后Pb~(2+)浓度降至0.037 mg/L,满足《地表水环境质量标准》(GB 3838-2002)Ⅲ类水体限值要求。研究结果可为农村铅污染水体修复提供理论和设计依据。 相似文献
11.
低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响 总被引：2，自引：2，他引：0
【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。 相似文献
12.
Kyle Devey Michael Mucalo Gordon Rajendram Joseph Lane 《Communications in Soil Science and Plant Analysis》2015,46(4):72-80
Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing. 相似文献
13.
《中国生态农业学报》2014,(8)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
14.
I.L. Boyd 《Biological conservation》2010,143(7):1664-1674
“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options. 相似文献
15.
Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage 总被引：1，自引：0，他引：1
Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate. 相似文献
16.
M.A. Callaham Jr. J.M. BlairT.C. Todd D.J. KitchenM.R. Whiles 《Soil biology & biochemistry》2003,35(8):1079-1093
The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils. 相似文献
17.
Grete Skrede Berit Karoline Martinsen Anne-Berit Wold Stein-Erik Birkeland Kjersti Aaby 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):193-208
Abstract A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species. 相似文献
18.
Yoav Bashan Bernardo Salazar Ma. Esther Puente Macario Bacilio Robert Linderman 《Biology and Fertility of Soils》2009,45(6):585-594
To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse
trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus
were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB;
the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons
reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened
later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons
growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants,
no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi,
enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant.
In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after
30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination
only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity
to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as
compost or PGPB can either amplify the effect or else attenuate it. 相似文献
19.
Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value. 相似文献
20.
《Communications in Soil Science and Plant Analysis》2012,43(7):865-877
Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L?1 nitric acid (HNO3) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L?1 ammonium acetate (NH4OAc) and 1.0 mol L?1 HNO3 extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils. 相似文献