应用顶空固相微萃取-气相色谱/质谱法分析杧果叶片挥发性物质成分

应用顶空固相微萃取法（HS-SPME）及气相色谱-质谱（GC/MSD）法进行本地种杧果叶片成分分析。结果共检测出68种挥发性成分,鉴定出其中的50个成分,含量占总挥发性组分的98.56%,其中主要成分为（n）-杜松萜烯（18.87%）、2,2,4,8-四甲基三环[5.3.1.0]8-十一烯（17.78%）、2,4,6-三甲基苯酚（12.94%）、,c-衣兰油烯（10.09%）、偄-杜松萜烯（-）-（8.14%）、香附子烯（5.64%）、（＋）-香橙烯（4.17%）等。分析结果从对本地种杧果叶片挥发性成分功能角度肯定其作为行道树的价值功效。     

不同发育时期椰子叶片精油的提取与成分分析

为明确引诱椰心叶甲[Brontispa longissima(Gestro)]取食的化学信息物质,利用同时蒸馏萃取法分别提取椰子(Cocos nucifera L.)的心叶、半展叶、老熟叶的精油,并采用气相色谱-质谱联用法对3者化学成分进行种类和含量的比较分析.结果表明,不同发育时期椰子叶片精油的主要成分为:2,3-二...     

金沙江干热河谷主要造林树种干季光合与蒸腾作用区域效应分析

植物光合与水分生理特征是植物逆境适应能力评价的重要参考指标。文中研究探讨了金沙江干热河谷8个主要造林树种光合与蒸腾作用在河谷上段鹤庆县和中段元谋县的空间差异及干季转向干热季时的时序差异。结果表明:河谷上段与中段的地理变化对供试树种的净光合速率(Pn)、蒸腾速率(Tr)及水分利用效率(WUE)具有明显影响,但树种不同,影响程度具有明显区别;随河谷上段及中段的地理变化,供试树种Pn在3月干季发生的升降变化与5月干热季一致,具有一定的季节稳定性。在由3月干季转向5月干热季过程中,随着干热胁迫的持续与加深,绝大部分供试树种Pn、Tr在河谷上段与中段间的差异愈趋显著。     

Uptake of lead by coen from roadside soil samples

Abstract

The uptake of Pb by young, greenhouse grown corn plants from roadside soil samples was found to be not only dependent upon the total amount of Pb in the soil, but also upon the amount of Pb in the soil relative to the soils capacity to sorb Pb. This is in agreement with the uptake of Pb by corn grown on soils amended with PbCl₂, although plant accumulation of Pb from roadside soils was much less than from PbCl₂ amended soils at comparable Pb concentrations. The use of crushed limestone as a road building material which results in high soil pH values next to the roadside is probably responsible for the reduced plant availability of Pb in the roadside soils.     

Dynamics of calcium‐sodium exchange under unsaturated plow conditions

Abstract

An experiment was conducted in soil columns of 84 cm length and 5.7 cm inner diameter to determine the effect of degree of water saturation on the extent of replacement of sodium by calcium from the exchange sites. The experiment was performed by running 0.20 N calcium chloride solution through a saline‐sodic soil into a water table at the lower end at different rates less than the infiltration rate of the soil, thus obtaining unsaturated flow conditions. The effective or the apparent calcium exchange capacity of the soil was reduced significantly and nearly proportionally with a decrease in the degree of water saturation during the flow process. It is suggested that part of exchange sites become inaccessible during the unsaturated flow and that there must be some isolated locations away from the main water stream in which mixing or molecular exchange by diffusion is negligible.     

不同有效钾提取方法的原理与效率比较

以6种典型含钾矿物为研究对象,探讨了盐溶液提取法、阳离子交换树脂法及四苯硼钠法等不同有效钾提取方法的原理、效率及影响因素的影响效应和机制。结果表明：盐溶液提取法对含钾矿物中钾的提取能力受离子种类、浓度及pH的影响,不同种类盐提取剂对矿物中钾释放的促进作用也因含钾矿物类型而异。NH4+ 使矿物层间塌陷,显著抑制各种矿物中非交换态钾的释放。阳离子交换树脂法对溶液中钾的提取能力与饱和离子种类及振荡强度有关。H+、Na+ 饱和树脂吸附溶液钾的能力大于Ca2+ 饱和树脂。振荡强度选为120 r/min可消除树脂法提取钾素时液膜扩散阻力的干扰。四苯硼钾的溶度积常数Ksp为2.40 × 10-8（25℃）。不加NaCl条件下,四苯硼钠浓度是影响四苯硼钠法对含钾矿物中钾的提取能力的主要因素。由不同方法的提取原理可以看出,铵盐类提取剂适用于速效钾为当季作物主要钾源（速效钾含量较高）的土壤钾素有效性的评价。而其他盐提取剂通过延长提取时间,可提取部分非交换态钾,可能较醋酸铵法更适合于提取非交换态钾为当季作物主要钾源的土壤有效钾。阳离子交换树脂法也可提取土壤非交换态钾,但操作较为繁琐,该方法更适用于原位研究土壤钾素的迁移、扩散等特性。四苯硼钠法提取效率较高,通过调节其提取力,可提取不同程度的非交换态钾,是具有较好应用前景的适于各类土壤和作物的土壤有效钾测定方法。     

耕地棕壤酸碱缓冲性能及酸化速率研究

辽宁省耕地棕壤自第二次土壤普查以来酸化趋势明显,pH整体平均值从第二次普查时期的6.42降至5.73。对辽宁省4个典型地区(昌图、沈阳、瓦房店、清原)的耕地棕壤耕层(0-20cm)缓冲性能、酸化速率及其影响因素进行研究,结果表明:各地区酸碱缓冲容量变幅为29.66～39.87mmol/kg.pH unit,其中辽宁北部和中部地区酸碱缓冲容量明显高于辽南和辽东地区。酸化速率以辽南地区下降速率最快,其值为2.69H+kmol/(hm2.a),而速率最慢的地区为辽东,其酸化速率为1.44H+kmol/(hm2.a)。土壤初始pH、阳离子交换量、颗粒组成及有机质含量均是影响酸碱缓冲容量变化的主要因素。北部和中部质地以粉(砂)壤土为主,阳离子交换量、盐基饱和度及粘粒含量均高于南部和东部地区,因此缓冲性能也较强。施肥及其他人为因素对辽宁耕地棕壤酸碱缓冲容量及酸化速率的影响有待进一步研究。     

Wet aggregate stability as affected by excess carbonate and other soil properties

Aggregate stability is a fundamental property influencing soil erodibility and hydraulic characteristics. Knowledge of soil components controlling aggregate stability is very important to soil structure conservation. The objective of this study, which was carried out in surface soils from central Greece, was to relate wet aggregate stability to selected soil properties, with emphasis on excessive free carbonate content. The wet‐sieving technique of air‐dried aggregates was used for structural stability evaluation, according to a test that calculates an instability index. The soils studied were developed on Tertiary marly parent material and ranged in calcium carbonate content from 5 to 641 g kg⁻¹. From the texture analysis before and after removal of carbonates, it was concluded that carbonates mainly contributed to total silt and sand fractions, that is to the mechanical fractions which, as a rule, negatively affect aggregate stability. The results of the correlation analysis showed that aggregate stability was positively affected by aluminosilicate clay content, cation exchange capacity (CEC) and Al‐containing sesquioxides. Clay fraction from carbonates and total sand and silt negatively affected aggregate stability. CEC has been proved a very significant determinant of aggregate stability, which in a hyperbolic form relationship with instability index explained 78·9 per cent of aggregate stability variation. Copyright © 2011 John Wiley & Sons, Ltd.     

不同有机物料对黑土及其复合胶体比表面积和电荷性质的影响

通过盆栽试验研究了施用动物粪便、动物残体、草本残体、木本残体4种不同有机物料对黑土胶体及黑土阳离子交换量(CEC)的影响。结果表明:不同来源有机物料对黑土胶体及黑土CEC的影响存在差异。与CK相比,动物粪便处理下黑土胶体比表面降低7.33%,而动物残体处理下提高了59.58%,木本残体提高了57.46%,草本残体提高了100.18%。pH<6时,各处理土壤胶体表面可变电荷量(Q表面)的曲线大致相似;在pH>6时,各有机处理土壤胶体样的表面电荷(Q样)均高于CK,并且动物粪便与木本残体的Q表面曲线相似且数值较高,CK与动物残体Q表面的曲线大致相同且数值较低。在pH为8～10时,各处理Q样由大到小依次为:动物粪便>木本残体>动物残体>草本残体>CK,动物粪便土壤胶体参比的表面电荷(Q参)与动物残体Q参的曲线大致相同并且数值较高,CK与草本残体Q参曲线相似且数值较低。不同来源有机物料对黑土CEC的影响也有所不同,动物粪便、动物残体、木本残体显著提高黑土CEC,而草本残体作用不明显。     

年产3万m^3中密度纤维板生产线气力输送系统的设计

通过对年产3万m~3中密度纤维板生产线铺装成型工段气力输送系统的设计,以及在设计中注意管网平衡计算、合理选择系统的技术参数及输送装置,实现干纤维的回收及输送,保证中密度纤维板生产线的正常生产.