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1.
荷花粉真空脉动干燥特性和干燥品质 总被引：9，自引：8，他引：1
为了缩短花粉的干燥时间,保证干燥品质,将真空脉动干燥技术应用于干燥新鲜荷花粉,研究了真空保持时间(15、12、9、6和3 min)、干燥温度(45、50、55、60和65℃)对干燥动力学、水分有效扩散系数、干燥活化能的影响,并运用Weibull分布函数模拟了花粉真空脉动干燥特性曲线;此外还研究了真空保持时间、干燥温度对花粉蛋白质含量以及微观结构的影响,并对干燥前后的花粉进行了色差分析。试验结果表明:Weibull分布函数能够很好地描述花粉的真空脉动干燥过程,结合尺度参数、形状参数计算出花粉真空脉动干燥水分有效扩散系数在2.154 2×10-11~6.254 3×10-11 m2/s之间;干燥活化能为20.88 k J/mol,表明新鲜荷花粉干燥每脱除1 kg水所需要的启动能量为1 160.00 k J;试验参数范围内,随着真空保持时间的减少,干燥后花粉蛋白质质量分数呈现先增加后减少的趋势;当干燥温度为45℃,真空常压脉动比为12 min:3 min时花粉蛋白质质量分数最高,为18.43%;扫描电镜结果显示,随着干燥温度的升高,花粉颗粒间致密程度降低,形成孔隙结构,这有助于干燥中水分的扩散迁移,花粉颗粒微观结构的完整性随着干燥温度的升高而降低;干燥前后花粉未发生色泽劣变。荷花粉真空脉动干燥的较佳参数为真空常压脉动比为12 min:3 min,干燥温度为45℃。研究结果为花粉真空脉动干燥技术的应用提供了理论依据和技术支持。 相似文献
2.
基于Weibull函数不同干燥方式下的茯苓干燥特性 总被引：3，自引：16，他引：3
为缩短干燥时间,克服茯苓块干燥后表面龟裂、易于破碎的缺陷,改善干燥品质;将自然晾晒、普通热风干燥、气体射流冲击干燥、真空脉动干燥4种技术应用于茯苓块的干燥,研究了茯苓的干燥特性;利用Weibull函数对其干燥曲线进行拟合并分析干燥过程,结合尺度参数、形状参数计算茯苓块的水分有效扩散系数、干燥活化能,并与Fick第二定律进行比较;测定了不同干燥条件下的破碎率、浸出物质量分数;并基于能耗、尺度参数、破碎率、浸出物质量分数对3种人工干燥方式进行了综合评价。结果表明:1)茯苓块在4种干燥方式下均表现为降速干燥,但普通热风干燥、真空脉动干燥前期存在升速段;2)Weibull函数能够准确拟合不同干燥方式下的干燥曲线;尺度参数随着温度、风速的增加而减小;形状参数与干燥方式有关,普通热风、真空干燥的形状参数值均大于1,气体射流干燥的形状参数值均小于1;3)基于Weibull函数计算水分有效扩散系数、干燥活化能,可克服Fick第二定律只适用于降速干燥的缺陷;估算的水分扩散系数范围为3.90×10-9~20.40×10-9 m2/s;干燥活化能为29.45~40.09kJ/mol,且不同干燥方式间的活化能存在差异;4)不同干燥方式下茯苓块破碎率存在显著性差异(p0.05);真空脉动与自然晾晒的破碎率均低于5.00%;试验参数范围内,气体射流的温度、风速与破碎率无相关关系,破碎率均值为62.68%;普通热风干燥方式下,破碎率随温度的升高而增大;5)真空脉动干燥方式下浸出物质量分数最高,为4.54%~4.75%;综合评价结果表明茯苓块的干燥宜采用真空脉动干燥技术。该研究探索了不同干燥技术下茯苓块的干燥特性和品质,为选择合适的干燥工艺提供了理论依据。 相似文献
3.
基于Weibull分布函数的马铃薯丁薄层热风干燥特性 总被引：4，自引：5，他引：4
为了实现马铃薯的规模化热风干燥,提高脱水制品的品质、降低生产能耗和成本,该文以薄层干燥试验为基础,研究了鲜切马铃薯丁在不同热风温度（40、50、60、70、80、90℃）、风速（0.5、1.0、1.5、2.5、3.5 m/s）和切丁长度（2.5、5、10、15 mm）条件下的干燥曲线、水分有效扩散系数和干燥活化能。利用Weibull分布函数拟合了干燥曲线,并建立了风温、风速和切丁长度与模型参数的定量关系。研究表明：鲜切马铃薯丁的热风干燥过程服从 Weibull 分布函数（R2=0.991～0.999）,是典型的降速干燥过程,模型的尺度参数与热风温度、风速和切丁长度有关;模型的形状参数与风速和切丁长度有关,而温度对其影响不显著（P＞0.05）;水分有效平均扩散系数在1.859～12.509×10-9 m2/s之间,与热风温度和风速显著相关（P＜0.05）,而物料切丁长度对其影响不显著（P＞0.05）;几何尺寸值与干燥物料的切丁长度和风速有关;马铃薯丁热风干燥的活化能为19.107 kJ/mol。该研究可为马铃薯热风干燥提供理论和技术基础。 相似文献
4.
干燥介质相对湿度对胡萝卜片热风干燥特性的影响 总被引：2，自引：17，他引：2
为了探究相对湿度和阶段降湿对热风干燥过程的影响,该文在干燥温度60℃、风速3.0 m/s条件下,研究了相对湿度(20%、30%、40%、50%)及第一阶段相对湿度50%保持不同时间(10、30、60、90 min),第二阶段相对湿度20%下,胡萝卜片的干燥特性和温度变化规律;利用Weibull分布函数对干燥曲线进行拟合并分析干燥过程,结合尺度参数估算水分有效扩散系数;基于复水比、色泽、干燥时间和能耗对不同相对湿度条件下的干燥过程进行评价。研究结果表明:相对湿度保持恒定条件下,干燥速率先上升后下降,且相对湿度越低干燥速率越大。降低相对湿度有利于缩短干燥时间,热风相对湿度20%比50%条件下干燥时间缩短了27.6%;分段降湿干燥条件下,热风相对湿度50%保持30min后降低为20%,其干燥时间比相对湿度恒定为20%条件下缩短了18.5%,干燥过程出现2个升速阶段;Weibull分布函数可以很好地描述胡萝卜恒定湿度和阶段降湿干燥过程。尺度参数α范围在1.864~3.635 h之间,形状参数β值在1.296~1.713之间,水分有效扩散系数在1.17×10-9~2.92×10-9 m2/s之间。对绿红值、复水率、能耗和干燥时间进行综合评价显示,热风相对湿度50%保持30 min干燥条件下绿红值最高为41.4,能耗相比于恒定相对湿度20%条件下减少了6.0%,复水比较高为3.81,综合评分较高为0.91。该文揭示了干燥介质相对湿度对胡萝卜片干燥特性的影响规律,对于优化干燥介质湿度控制策略以提高干燥速率和品质,降低干燥能耗提供了科学依据和技术支持。 相似文献
5.
热风干燥联合真空降温缓苏提升黄秋葵干制品品质 总被引：4，自引：3，他引：1
为提升黄秋葵热风干燥产品品质,试验将真空降温缓苏技术应用于黄秋葵热风干燥过程中。研究了不同缓苏时长下黄秋葵干燥特性和品质指标的变化规律;利用Weibull分布函数分析缓苏处理对黄秋葵热风干燥过程中水分扩散机制的影响;采用一元非线性回归分析构建适用于黄秋葵真空降温缓苏-热风联合干燥过程中干燥特性和品质指标随缓苏时长变化的学数模型;以总干燥耗时、总干燥能耗、复水比、色相角以及总营养物质保存率为指标,对不同缓苏时长下的黄秋葵热风干燥进行加权综合评价。结果表明：缓苏处理能够提升黄秋葵热风干燥速率,且随着缓苏时长的延长其促进作用会增强;Weibull分布函数能够准确描述（R2>0.99且离差平方和χ2处于10-4数量级）黄秋葵真空降温缓苏-热风联合干燥过程中水分比随干燥时间的变化规律;常用函数一元非线性回归分析能够构建出黄秋葵真空降温缓苏-热风联合干燥过程中各干燥特性和品质指标随缓苏时长的变化规律的动力学模型;联合干燥过程中,缓苏60 min处理的综合评分值最高为0.55,在干燥温度和风速分别为60℃、1.5 m/s条件下,该缓苏时长较适合应用于黄秋葵热风干燥。研究表明,真空降温缓苏处理能够提升黄秋葵热风干燥的干燥速率和干燥品质,该文可为真空降温缓苏技术在高品质黄秋葵干制品工业生产上的应用提供理论依据。 相似文献
6.
为了研究污泥薄层干燥的动力学模型、明确薄层干燥模型选取原则、分析模型参数影响因素及在干燥中应用,该研究搭建了污泥干燥试验台,对不同干燥温度(50、75、100、125℃)、不同风速(0.5、1.0、1.5、2.0 m/s)与不同污泥厚度(5、10、15、20mm)的污泥进行干燥试验,利用Weibull分布模型对其干燥动力学曲线进行模拟并分析,建立了风温、风速和污泥厚度与模型参数的定量关系。从原模型与改进模型、因变量与自变量转换、多参数模型及初始条件等4个角度分析,选择Lewis、Page、Two-term exponential和Weibull分布模型进行拟合分析,发现污泥的热风干燥过程服从Weibull分布模型(R2=0.994～0.997),是典型的降速干燥过程,降速阶段存在第一、第二降速段,模型的尺度参数(α)和形状参数(β)均与热风温度、风速和污泥厚度有关;第二降速段扩散系数大于第一降速段扩散系数,第一降速段活化能变化范围为12.91～17.12 kJ/mol,第二降速段活化能变化范围9.56～15.05kJ/mol。研究结果可为污泥干燥工艺参数优化及干燥... 相似文献
7.
哈密瓜片气体射流冲击干燥特性和干燥模型研究 总被引：7，自引：6，他引：1
本文将气体射流冲击干燥技术应用于哈密瓜片的干燥,研究了其在不同干燥温度（60、65、70、75和80℃）和风速（5、10、15和20 m/s）下的干燥曲线、水分有效扩散系数以及干燥活化能,并建立了气体射流冲击哈密瓜片的数学模型。研究结果表明：哈密瓜片的整个干燥过程属于降速干燥,水分有效扩散系数在2.38-4.55×10-9 m2/s的范围内随着干燥温度和风速的升高而升高;通过阿伦尼乌斯公式计算出了哈密瓜片的干燥活化能为29.44 kJ/mol。根据R2、RMSE和X-2得出,Modified Page方程能很好的预测哈密瓜片气体射流冲击干燥的水分比变化规律,该模型与气体射流的温度和风速有关,并得到了各参数的数值和模型表达式。 相似文献
8.
南瓜片真空脉动干燥特性及含水率预测 总被引：5，自引：3，他引：2
为探索南瓜片真空脉动干燥特性,并实现干燥过程中南瓜的含水率预测,该文研究了不同常压保持时间、真空保持时间、干燥温度和切片厚度对南瓜干燥时间和速率的影响;利用温度传感器实时采集南瓜在干燥过程中的中心温度,阐述压力脉动过程对物料传热传质的影响;建立了输入层个数为5,隐藏层个数为11,输出层为南瓜含水率,结构为"5-11-1"的BP神经网络模型,实现对南瓜含水率实时预测.结果表明:真空保持时间和常压保持时间均对南瓜干燥时间有显著影响,干燥温度60℃,切片厚度7mm条件下,常压保持时间10min和真空保持时间9min所用干燥时间最短,约为352min;干燥温度和切片厚度均对干燥时间有显著影响,提高干燥温度、减少切片厚度能够有效缩短干燥时间.采用Levenberg-Marquardt算法为训练函数,经过有限次训练得到的BP神经网络模型,其预测值与实测值之间的决定系数R2为0.9968,均方根误差RMSE为0.0173,能够很好预测南瓜在真空脉动干燥过程中的含水率.研究结果为南瓜真空脉动应用以及含水率在线预测提供理论依据. 相似文献
9.
为研究腐殖酸肥料射频真空干燥特性及品质,该研究探讨了不同极板间距（160、165 mm）、不同初始湿基含水率（10%、15%、20%）下腐殖酸肥料的升温速率和加热均匀性,在此基础上进行射频真空干燥试验,并以热风干燥试验为对照,采用Weibull函数拟合腐殖酸肥料射频真空干燥特性曲线,对比射频真空干燥与热风干燥对腐殖酸肥料颜色、总氮、总磷、总钾及有机质的影响。结果表明：真空度为0.085 MPa,极板间距为160 mm、初始湿基含水率为15%时,干燥速率和升温速率较快,加热均匀性较好;升温曲线在53 ℃出现拐点,53 ℃前升温较快,53 ℃后升温较慢;除含水率为20%的物料外,极板间距对加热均匀性影响不显著（P > 0.05）,但初始湿基含水率对其有显著影响（P<0.05）;射频真空干燥所需时间较热风干燥缩短约208 min,射频真空干燥可显著提高干燥速率（P<0.05）;Weibull函数能较好的拟合腐殖酸肥料射频真空干燥过程,尺度参数和形状参数随极板间距的减小而减小,随初始湿基含水率的增加呈先减小后增大的趋势;水分有效扩散系数,随极板间距的减小而增大,随初始湿基含水率的增加,呈先增大后减小的趋势;极板间距与初始湿基含水率总体上对腐殖酸肥料的色泽高度L*、红绿值a*、蓝黄值b*、总氮、总磷、总钾、有机质无显著影响（P>0.05）;65 ℃热风干燥后样品的色差值显著高于射频真空干燥（P<0.05）,总氮和有机质含量显著低于射频真空干燥（P<0.05）。在设置的试验条件下,腐殖酸肥料的较佳干燥参数为真空度0.085 MPa、极板间距160 mm、初始湿基含水率15%。研究结果可为腐殖酸肥料射频真空干燥应用提供参考。 相似文献
10.
哈密瓜片气体射流冲击干燥特性和干燥模型 总被引：3，自引：1，他引：2
为了提高哈密瓜制干品质、缩短干燥时间,该文将气体射流冲击干燥技术应用于哈密瓜片的干燥,研究了其在不同干燥温度（60、65、70、75和80℃）和风速（5、10、15和20 m/s）下的干燥曲线、水分有效扩散系数以及干燥活化能,并建立了气体射流冲击干燥哈密瓜片的数学模型。研究结果表明：哈密瓜片的整个干燥过程属于降速干燥,水分有效扩散系数在2.38～4.55×10-9 m2/s的范围内随着干燥温度和风速的升高而升高;通过阿伦尼乌斯公式计算出了哈密瓜片的干燥活化能为29.44 kJ/mol。通过决定系数R2、均方误差的根（RMSE）和卡方检验值（2）等拟合优度评价指标对各种干燥模型进行评价,结果表明：Modified Page模型能很好的预测哈密瓜片气体射流冲击干燥过程中的水分比变化规律。该研究为使用气体射流冲击技术工业化干燥哈密瓜提供了技术依据。 相似文献
11.
【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.
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
15.
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
16.
《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
17.
Y. Bashan J. J. Bustillos L. A. Leyva J.-P. Hernandez M. Bacilio 《Biology and Fertility of Soils》2006,42(4):279-285
Inoculation of wheat seedlings with the plant growth-promoting bacterium Azospirillum brasilense Cd was immobilized in alginate microbeads and, without applying any stress, significantly increased the quantity of several
photosynthetic pigments, such as chlorophyll a, chlorophyll b, and the auxiliary photoprotective pigments violaxanthin, zeaxanthin, antheroxanthin, lutein, neoxanthin, and β-carotene.
This resulted in greener plants with no apparent visible stress. After monitoring the quantity of photosynthetic pigments
for 4 weeks, we observed that inoculated plants had higher quantities of pigments in shoot and stem. The greatest difference
in the quantity of all pigments between inoculated and noninoculated plants occurred in the first week of growth. Regardless
of treatment, the quantity of pigments in stems was three to four times less than the quantity of these pigments in shoots.
Application of Azospirillum, either as liquid inoculant or as alginate microbeads, did not alter the positive effect of the bacteria on pigment production
or the positive response of the plants towards A. brasilense Cd inoculation. 相似文献
18.
Dhritiman Ghosh Velusamy Srinivasan Olli H. Tuovinen Aaron Peacock Mark Radosevich 《Soil biology & biochemistry》2009,41(6):1331-1334
We examined the community composition of microbes that colonized atrazine-containing beads buried in agricultural soils that differed in atrazine treatment history. Bacterial abundance was 5-40-fold greater in atrazine-fortified beads. In beads containing 20 mg atrazine kg−1 buried in soil with a history of atrazine application (conditioned soil), the abundance of Actinobacteria increased approximately 80-fold whereas in control soil, Actinobacteria were enriched only 10-fold and the gamma-Proteobacteria and Planctomycetes increased by 60- and 25-fold, respectively. The gamma-Proteobacteria were enriched by 120- and 230-fold in beads containing 200 mg atrazine kg−1 in conditioned and control soil, respectively. The results demonstrate that BioSep® beads are a suitable matrix for recruiting a diverse subset of the bacterial community involved in atrazine degradation. 相似文献
19.
Pilar García Juan-Vicente Monte Carlos Casanova Consuelo Soler 《Genetic Resources and Crop Evolution》2002,49(1):103-109
Arbitrary oligonucleotides were used as primers to amplifygenomic DNA of 48 wild Spanish populations of Agropyroncristatum, Elymus hispanicus,E. caninus,E. repens,Thinopyrum curvifolium, Th.junceum and Th.intermedium. Genetic diversity was analysedusing nineteen primers. The number of amplified products ranged from8 to 18 per primer and a total of 240 markers were scored. Differentlevels of intraspecific genetic diversity were found, the allogamousspecies E. repens andTh. intermedium being themost variable. Jaccard's similarity coefficients for internalmeasure within and between populations were used to produce a clusterdiagram. The results demonstrate differences in the degree ofsimilarity between taxonomic units. Interpopulational variability andinterspecific genomic relationships of these species arediscussed. 相似文献
20.
The effects of three commonly used fungicides on the colonization and sporulation by a mixture of three arbuscular mycorrhizal (AM) fungi consisting of Glomus etunicatum (Becker & Gerd.), Glomus mosseae (Nicol. & Gerd.) Gerd. & Trappe, and Gigaspora rosea (Nicol. & Schenck) in symbiosis with pea plants and the resulting response of the host-plant were examined. Benomyl, PCNB, and captan were applied as soil drenches at a rate of 20 mg active ingredient kg-1 soil 2 weeks after transplanting pea seedlings in a silty clay-loam soil containing the mixed inocula of AM fungi (AM plants). Effects of fungicides were compared to untreated plants that were inoculated with fungi (AM control). The effect of mycorrhizal inoculation on plant growth was also examined by including nonmycorrhizal, non-fungicide-treated plants (non-AM control). Fungicides or inoculation with AM fungi had only a small effect on the final shoot weights of pea plants, but had greater effects on root length and seed yield. AM control plants had higher seed yields and lower root lengths than the corresponding non-AM plants, and the fungicide-treated AM plants had intermediate yields and root lengths. Seed N and P contents were likewise highest in AM control plants, lowest in non-AM plants, and intermediate in fungicide-treated AM plants. All three fungicides depressed the proportion (%) of root length colonized by AM fungi, but these differences did not translate to reductions in the total root length that was colonized, since roots were longer in the fungicide-treated AM plants. Pea plants apparently compensated for the reduction in AM-fungal metabolism due to fungicides by increasing root growth. Fungicides affected the population of the three fungi as determined by sporulation at the final harvest. Captan significantly reduced the number, relative abundance, and relative volume of G. rosea spores in the final population relative to the controls. The relative volume of G. etunicatum spores was greater in all the fungicide-treated soils, while G. mosseae relative volumes were only greater in the captan-treated soil. These findings show that fungicides can alter the species composition of an AM-fungal community. The results also show that AM fungi can increase seed yield without enhancing the vegetative shoot growth of host plants. 相似文献