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1.
等离子体辅助玉米醇溶蛋白电诱导沉积成膜的工艺优化 总被引：1，自引：1，他引：0
天然玉米醇溶蛋白（Zein）具有良好成膜特性,但其在成膜过程中蛋白无序排列导致膜结构不稳定,限制了实际应用。该研究基于玉米醇溶蛋白的电荷特性,将玉米醇溶蛋白置于平行匀强电场下,诱导蛋白有序自组装排列并沉积成膜,且在诱导液中引入低温等离子体预处理以提高诱导效率。分别探究了玉米醇溶蛋白浓度、溶液pH值以及电流密度对蛋白沉积率的影响,并通过Box-Behnken优化试验获得了最佳沉积工艺为Zein浓度139.5 mg/mL,Zein溶液pH 值为8.17,电流密度14.3 A/m2,在优化条件下,玉米醇溶蛋白的沉积率可达1.120 mg/cm2,显著高于未经等离子体处理的沉积率0.483 mg/cm2,表明等离子体辅助可有效提高电诱导中玉米醇溶蛋白的沉积率。扫描电子显微镜图像显示采用等离子体辅助电诱导制备的沉积膜表面更平整、光滑。傅里叶红外光谱分析表明,电诱导可使玉米醇溶蛋白二级结构中β-转角和无规则卷曲结构向β-折叠及α-螺旋结构转化。研究结果为电诱导玉米醇溶蛋白成膜技术提供参考,有利于拓展低温等离子体在蛋白质领域的应用。 相似文献
2.
为明确热处理过程中肌肉蛋白与萜类化合物的相互作用规律及机制,以肌原纤维蛋白（myofibrillar protein,MP）和肌浆蛋白（sarcoplasmic protein,SP）为研究对象,测定不同加热时间下表面疏水性、总巯基含量、粒径、二级结构含量等理化特性。选取炖煮猪肉中3种关键萜类化合物（3-蒈烯、柠檬烯、芳樟醇）,结合气相色谱-质谱联用,探究热处理过程中MP和SP对萜类化合物吸附能力与蛋白构象变化的相关性,并通过分子对接揭示肌肉蛋白与萜类化合物结合机制。结果表明：随加热时间延长,MP和SP的表面疏水性和总巯基含量先上升后下降,粒径持续上升,α-螺旋结构转化为β-折叠和无规则卷曲结构。加热5 min内,MP和SP二级结构展开,结合位点暴露,对萜类化合物吸附能力增强;继续加热后,MP和SP聚集使结合位点被掩埋,对萜类化合物吸附能力降低,且由于SP更高的聚集程度,加热10～60 min内吸附能力弱于MP。分子对接结果证明,疏水相互作用为3-蒈烯和柠檬烯与肌肉蛋白结合的主要驱动力,而芳樟醇通过疏水相互作用和氢键与肌肉蛋白结合。结果表明热处理可以通过改变肌肉蛋白构象控制风味结合位点暴露或掩埋,从而影响肌肉蛋白与萜类化合物的相互作用,研究结果可为热加工肉制品的风味调控提供理论指导。 相似文献
3.
传统浇铸法制备的玉米醇溶蛋白薄膜表面粗糙,机械性质及耐水性较差。为了改善玉米醇溶蛋白理化性质,在传统浇铸法膜制备过程中引入平行匀强电场(1~5 A/m2)处理蛋白成膜液。经过电场处理后,玉米醇溶蛋白表面光滑、形状完整。试验结果表明:电场处理可改善薄膜力学性质、表面疏水性、水蒸气透过率等性质;随着电流密度的增大,薄膜拉伸强度、断裂伸长率、水蒸气透过率、吸水率以及表面接触角呈现规律性增加或者减小;电场处理下薄膜热特性改变,与未处理组相比变性温度略有提高,最大增幅为19.5℃。当电流密度为4 A/m2时,薄膜理化性质较佳:拉伸强度、断裂伸长率分别为73.09 MPa和9.68%,吸水率降低至14.87%,水蒸气透过率为2.55×10-8 g·m/(m2·h·Pa),静态接触角为62.18°,变性温度提高到118.39℃,热稳定性提高,薄膜表面光滑。电场可诱导成膜液中分子有序性排列,提高薄膜均一性;通过调节电流密度可得到具有一定力学强度和亲/疏水性的薄膜。试验结果为制备具有特定功能性的纯玉米醇溶蛋白薄膜材料提供了理论依据。 相似文献
4.
利用环境生长室探讨不同CO2浓度和土壤水分亏缺处理下玉米植株生物量、气孔形态与分布特征、叶片气体交换参数、叶绿素荧光参数等生长及生理指标的变化规律。以‘郑单958’ 玉米品种为试材,利用环境生长室设置2个CO2浓度和4个土壤水分梯度对玉米进行CO2浓度和水分处理。结果表明：1）不同程度土壤水分亏缺均显著降低玉米地上生物量（P<0.05）,但CO2浓度升高增加了轻度水分亏缺条件下玉米地上生物量（P<0.01）和总生物量（P<0.01）。2）大气CO2浓度升高导致轻度和中度水分亏缺条件下玉米的净光合速率（Pn）分别提高15.8%（P<0.05）和25.7%（P=0.001）,而CO2浓度升高却降低了玉米叶片蒸腾速率（P<0.001）和气孔导度（P<0.001）,最终导致玉米瞬时水分利用效率均显著提高（P<0.001）。3）不同水分处理对玉米叶片气孔密度和单个气孔形态特征均造成显著影响（P<0.01）。因此,大气CO2浓度升高可以增加轻度水分亏缺条件下玉米叶片氮含量、叶片非结构性碳水化合物含量和光合电子传递速率,从而提高玉米植株的生物量累积以及叶片碳同化能力和水分利用效率。研究结果将为深入理解气候变化背景下玉米对大气CO2浓度升高和土壤水分亏缺的生理生态响应机制提供科学依据。 相似文献
5.
超高压处理玉米醇溶蛋白的流变性和热特性分析 总被引：3，自引：3，他引：0
为了阐明超高压处理对玉米醇溶蛋白流变行为和热性能的影响及其作用规律,采用旋转黏度计测定了不同温度条件下超高压处理玉米醇溶蛋白溶液的流变特性参数,应用幂定律拟合了剪切应力(τ)与剪切速率(γ)的关系曲线,建立了黏度(η)和温度(T)的数学模型;利用差示扫描量热仪(DSC)测定了超高压处理前后玉米醇溶蛋白的结晶温度(Tc)、熔融温度(Tm)、结晶焓(ΔHm),并利用扫描电子显微镜(SEM)对其进行了表征。结果表明,超高压处理后玉米醇溶蛋白溶液逐渐偏离牛顿流体,具有假塑性流体特性。随着压力增大,黏度呈现先增加后减小再增加的趋势,当压力为400MPa时,黏度达到最高;随着温度升高,黏度开始下降,当温度为40℃时,黏度降到最低;而随着剪切速率的增大,黏度随之下降,但当剪切速率接近100s-1时,黏度变化不明显。超高压处理后玉米醇溶蛋白粉的熔融温度升高,结晶焓减小,DSC热特性曲线变性峰(Tm-Tc)有变宽的趋势。SEM显示超高压处理后部分玉米醇溶蛋白颗粒凝聚成环状或者链状结构。 相似文献
6.
食品温度及F值/C值计算机实时采集显示系统的研制 总被引：1，自引：0，他引：1
在流态化固体食品超高温杀菌中，可采用静态颗粒法记录杀菌全程颗粒的中心温度，尽管热电偶限制了颗粒运动及表面换热，但在颗粒之间传热学特性相同的情况下，被测定颗粒是系统最冷颗粒，这样首次出现的超高温杀菌条件下固体颗粒食品中心温度及杀菌动力学参数实时采集计算的需要。因此研制了一种基于Visual Basic6.0，能够完成数据采集和积分运算的食品温度和F值/C值计算机实时采集显示系统。温度传感器采用超细热电偶以适用于小尺寸颗粒。该系统的温度、压力及F值/C值测量准确度分别为±0.1℃、±0.005 MPa及±2.3%。在流态化固体食品超高温杀菌原理验证设备上应用该系统对马铃薯颗粒的进行多路温度采集，F值/C值计算及数据实时显示，证明该系统适用于超高温条件下的食品颗粒杀菌的验证和记录。 相似文献
7.
玉米/大豆带状套作可以充分利用光环境,提高单位土地面积物质产出。为探明玉米/大豆带状复合种植模式下不同空间配置对大豆冠层光环境、形态、产量及系统效益的影响,进而为大豆高产优质栽培提供依据,本研究选用半紧凑型（‘川单418’）和紧凑型（‘荣玉1210’）玉米品种与大豆带状套作,固定带宽为200 cm,玉米采用宽窄行种植,玉米窄行距设置3个处理：20 cm、40 cm、60 cm;并以单作大豆（SS）作为对照。分析透光率、形态、光合色素、荧光参数、生物量和系统产量的变化规律。结果表明：套作大豆冠层透光率、红光/远红光（R/FR）比值随玉米窄行距的增大而逐渐降低;套作下大豆茎粗、节数、茎干重和全叶干重均随玉米窄行距增大呈降低趋势,最大值出现在玉米窄行距20 cm处理下;与单作大豆相比,两个玉米品种下大豆茎粗、节数、茎干重和全叶干重均显著降低,而第2节间长和主茎长显著升高。套作下大豆叶片光合色素含量随玉米窄行距的增大而逐渐降低,各行距处理及不同玉米品种下套作的叶片光合色素含量均低于单作大豆。大豆叶片荧光参数Fv/Fm、NPQ、Fq''Fm''和Fq''/Fv''随玉米窄行距的增大均呈先增大后减小的趋势,而Fo变化趋势与之相反。玉米收获后,大豆光环境得到改善并迅速恢复生长,套作大豆形态生理指标与单作差异减小,但由于前期玉米的遮荫,各套作处理间大豆产量差异仍显著。通过系统效益分析,在玉米窄行距40 cm处理下,套作系统综合产量最高,两玉米品种下玉米、大豆产量平均分别为8 559.52 kg·hm-2、1 717.60 kg·hm-2,土地当量比平均达1.57。本试验中大豆与两个株型玉米套作,大豆形态生理指标差异影响不显著。因此,选择紧凑或半紧凑玉米品种,适度缩小玉米窄行距可以显著改善带状套作大豆的生长环境,提高其生物量和产量。 相似文献
8.
被动荧光探测水分胁迫对玉米叶片影响的初步研究 总被引：4，自引：2，他引：4
利用叶绿素荧光被动探测方法初步探讨了水分胁迫对玉米叶片生理机能的影响。水分胁迫梯度通过将离体叶片放在干燥器时间不同而获得。室内采用积分球耦合ASD光谱仪，结合加/不加滤光片照明的方法得到反射率差值光谱，即代表叶绿素荧光光谱。结果表明随着叶片含水率的降低，叶绿素荧光发射峰的位置几乎没有变化，峰高在686 nm处有先上升后逐渐降低的趋势，在740 nm处则缓慢下降。双峰比值Dif686/Dif740与叶片含水率呈负相关关系(R2=0.3850，n=21)，不同水分胁迫程度下利用调制式荧光仪测定的荧光参数Fv/Fm与740 nm荧光光谱峰值线性正相关，与双峰比值有负相关趋势。表明该被动方法可以探测水分胁迫引起的叶片光系统受胁状况，为田间被动遥感探测植物叶绿素荧光和生理状态提供参考。 相似文献
9.
黄米醇溶蛋白脱色工艺研究 总被引：1，自引：0，他引：1
该文采用有机溶剂、颗粒活性炭、凝胶层析、超临界CO2流体萃取等方法，研究了黄米醇溶蛋白的脱色效果及脱色后蛋白的回收率。结果显示甲苯脱色效果好，蛋白质回收率较高，但工艺繁琐，成本高；凝胶层析费时，而且处理量有限，在生产中会受到限制；颗粒活性炭成本低，脱色效果较好，工艺简单，可大量处理样品；超临界CO2流体萃取在脱色效果和蛋白质回收率上都优于其他方法，且不需后处理即可直接得到脱色蛋白成品。因此，颗粒活性炭、超临界CO2流体萃取脱色工艺适合于不同层次的无色黄米蛋白的工业化生产。 相似文献
10.
为研究旱涝急转对玉米叶片衰老特性和产量的影响,以春玉米“宜丹629”为供试材料,2021年在测坑条件下,设置拔节期旱（drought,D）、涝（waterlogging,W）、旱急转轻涝（drought-light waterlogging,D-LW）、旱急转中涝（drought-moderate waterlogging,D-MW）、旱急转重涝（drought-heave waterlogging,D-HW）、和正常供水（control,CK）6个处理。测定不同处理组合下玉米大喇叭口期、抽雄期和灌浆期叶片叶绿素仪（soil and plant analyzer development,SPAD）值、过氧化物歧化酶（superoxide dismutase,SOD）、过氧化物酶（peroxidase,POD）、过氧化氢酶（catalase,CAT）活性、丙二醛（malondialdehyde,MDA）、可溶性蛋白含量和净光合速率（net photosynthetic rate,Pn）,成熟期籽粒产量及其构成。结果表明,与CK相比,D-LW处理抽雄期和灌浆期玉米叶片的SPAD值、SOD、POD、CAT活性、可溶性蛋白含量、Pn及成熟期穗数、穗粒数和千粒质量差异不显著,使其籽粒产量维持在较高水平（7810.3 kg/hm2）。说明旱急转轻涝不会加速玉米叶片的衰老,从而稳定籽粒产量。而其他水分胁迫处理显著降低各监测时期玉米叶片SPAD值、SOD、POD、CAT活性、可溶性蛋白含量和Pn,明显提高MDA含量,使穗数、穗粒数和千粒质量减少,最终显著降低产量（较CK的值下降13.3%~72.7%）。整体上,D-MW和D-HW处理明显加速玉米叶片衰老,严重抑制最终产量。综上,拔节期旱后急转轻涝对玉米叶片SPAD值、抗氧化酶活性、可溶性蛋白含量和Pn有补偿作用,从而获得较高的籽粒产量。该研究结果为玉米应对旱涝急转灾害和灌排管理提供一定理论依据。 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.
Aleš Lebeda Ivana Doležalová Eva Křístková Barbora Mieslerová 《Genetic Resources and Crop Evolution》2001,48(2):153-164
Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions. 相似文献
13.
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
14.
Thomas Larsen Jesper Luxhøi Jakob Magid Lars Stoumann Jensen Paul Henning Krogh 《Biology and Fertility of Soils》2007,44(1):59-68
We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization
and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition
with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the
decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots
with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass,
soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration,
N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially
(<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation
in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils,
indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but
the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation
for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community
performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea. 相似文献
15.
《中国生态农业学报》2014,(6)
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
16.
《中国生态农业学报》2014,(7)
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
17.
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
18.
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
19.
《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
20.
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