Possible emissions of N2O from plants in coniferous-deciduous mixed forests

Aboveground vertical profiles of N₂O concentrations were measured within two natural coniferous-deciduous mixed forests of 1998 and 1999 in Changbal Mountain. Significant high N₂O concentrations were found in six profiles out of twelve profiles. The results showed that high concentrations were 3.03% to 64.9% higher than the “normal concentrations” in these six profiles. Differences between the high concentrations and the “normal concentrations” were statistically significant. The simultaneous occurrence of high concentrations at/nearby the canopy height and normal concentrations at the trunk space height indicated an efflux of N₂O from portant source of atmospheric N₂O in a forest ecosystem. Foundation item: This paper was supported by the National Natural Science Foundation of China (23916261) and the “Hundred Scientists” Project of Chinese Academy of Sciences. Biography: XU Hui (1967-), male, Ph. Doctor, associate research fellow in Laboratory of Ecological Process of Trace Substance in Terrestrial Ecosystem, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110015 P. R. China. Responsible editor: Song Funan     

落叶松多硫化钠制浆研究

对落叶松的多硫化钠法（简称ＰＳ）与硫酸盐法（简称ＫＰ）纸浆得率进行比较，发现在本实验的条件下，特别是正交实验时，多硫化钠法的纸浆得率有效显著的提高。另外，残碱中硫化钠浓度分析说明，多硫化钠法和硫酸盐法有截然不同的变化规律。     

Experimental study on the influence of percolation patterns on the removal of soluble elements in stratified alluvial-soil paddy fields for rice

The dynamics of substances in percolating water was investigated using paddy field models planted with rice and fertilized. Percolation patterns mimicking the plow layer and plow sole were set up in these models for closed system percolation. In one of these models, in which the groundwater level was kept high, the percolation pattern of the subsoil layer was set up as closed system percolation. In another model with a lower groundwater level, the percolation pattern of the portions above and below the groundwater level was set up as open and closed system percolation, respectively.The results show that the concentrations of nitrate nitrogen and nitrite nitrogen in percolating water were higher in the upper portion of the subsoil layer with open system percolation than in the plow layer and plow sole with closed system percolation, while these concentrations tended to be lower in the lower portion of the subsoil layer with closed system percolation than in the plow layer and plow sole. Iron and manganese concentrations in the subsoil layer were higher in the portion with closed system percolation than those in the portion with open system percolation. The concentrations of bases such as calcium tended to increase with the increase in iron concentrations in soil water.     

Relationship of protein concentration and water content of equine serum and plasma samples

A highly significant correlation between the water content and protein concentration of equine serum and plasma samples was demonstrated over a wide range of concentrations. A close correlation was also observed between protein concentration as estimated by refractometry and as determined by the biuret procedure for equine serum and plasma samples.     

考虑传输约束与成本差异的电力市场供应集中度量方法研究

在实施反垄断法时常常使用HHI指标来度量市场集中程度,然而当电力市场供应方之间存在地理位置和成本差异时,使用HHI指标测量市场力就会失效.本文基于区域边际定价机制,提出了一种针对电力市场的HHI型指标,并用实例说明了这种HHI型指标具有预测电力市场力的能力.     

盐胁迫对龙柏的影响

采用盆栽试验,在日光温室大棚内通过设置不同盐分(Na Cl)浓度对龙柏进行胁迫试验,并对在不同盐分浓度胁迫下成活率、胞膜透性、丙二醛含量及脯氨酸含量的变化进行分析。结果表明,龙柏为强耐盐植物,在盐分浓度为5 g/kg时,成活率仍达100%;随着胁迫时间的延长,龙柏细胞膜透性、丙二醛含量及脯氨酸含量均呈现先增后降的趋势,且在一定的处理时间内均与盐溶液浓度呈正相关。     

超高产冬小麦四种微量元素的积累及其与产量性状的关系

为了明确超高产冬小麦锰、锌、铜、硼的吸收积累特点及与产量相关性状的关系,于2005-2006年冬小麦成熟期测定了不同小麦品种产量相关性状及植株和籽粒中锰、锌、铜、硼的含量与积累量。结果表明,成熟期不同冬小麦品种植株和籽粒中4种元素的含量和积累量存在不同程度的差异,但都表现为锰>锌>铜>硼。植株锰积累量与穗粒数呈显著正相关,植株锰含量和积累量与单株成穗数呈显著负相关。植株和籽粒锌含量和积累量与每穗小穗数、结实小穗数和穗粒数呈正相关,与不孕小穗数呈负相关,但相关均未达到显著水平。植株铜含量与每穗小穂数、结实小穗数、穗粒数和产量均为正相关,且相关达到显著或极显著水平。植株铜积累量与总小穗数、结实小穗数呈显著正相关,与不孕小穗数呈显著负相关。植株硼积累量与产量达到显著正相关水平。综合分析可知,4种微量元素在增加产量和优化产量构成因素中起着不同的作用,在小麦生产中应针对具体的限制因素确定不同微量元素肥料的施用技术。     

蓝藻伪空胞的测定及其前处理方法(英文)

[目的]探讨蓝藻伪空胞的测定及其前处理方法。[方法]改进了测定伪空胞的毛细管压力法,对改进后的装置进行了检测限和精密度测试,并研究了2种浓缩方法和2种保存方法对3种蓝藻细胞数量和伪空胞含量的影响。[结果]改进后的蓝藻伪空胞测定装置其检测限达到0.0018μl/ml藻液,同一样品测定结果相对标准偏差小于1%。采用过滤和离心2种浓缩方法时,分散单细胞的微囊藻细胞损失都大于50%,其中小群体的微囊藻采用离心的方法细胞损失较小,而丝状的颤藻采用过滤的方法损失较小;这2种方法对伪空胞含量的影响均可忽略。3种蓝藻在直接冷藏和添加鲁哥试剂保存7d后,其细胞浓度和单位细胞的伪空胞含量均未发生明显改变,其中对于伪空胞,直接冷藏的损失更小;对于自然水体样品,宜添加鲁哥试剂进行保存。[结论]为研究蓝藻浮力调节机制及其暴发机理提供了理论依据。     

卡那霉素对盐芥生长的影响

[目的]研究不同浓度的卡那霉素对盐芥生长的影响。[方法]选用盐芥山东生态型的种子,种于含不同浓度卡那霉素的Ms0培养基上,观察盐芥对不同浓度卡那霉素的敏感程度。[结果]随着卡那霉素浓度的增加,盐芥的生长受到不同程度的抑制。[结论]卡那霉素可以作为一种筛选标记对转基因盐芥进行筛选。     

人力资本集聚与县域企业竞争力提升的研究

人力资本是促进县域产业结构优化的核心驱动要素,县域人力资本的集聚是产业结构优化的重要前提。基于这种思路,对县域人力资本的集聚以及其对产业竞争力的影响进行较为深入的研究。指出了广东省县域人力资本产业结构存在的问题和不足,提出了优化人力资本结构并提升人力资本水平的建议。