Terpenes and phenolics in response to nitrogen fertilization: A test of the carbon/nutrient balance hypothesis

Nitrogen fertilization resulted in a linear increase in the growth ofAbies grandis seedlings, but linear decrease in foliage concentrations of phenolic compounds. These data are consistent with the inverse relationship between growth and production of carbonbased secondary chemicals predicted by the carbon/nutrient balance (CNB) hypothesis. However, in contrast to predictions of the CNB hypothesis, nitrogen fertilization had no effect on foliage terpene concentrations. The results suggest that not all carbon-based chemicals respond in the same manner to environmental variation, and that the carbon/nutrient balance hypothesis does not adequately explain all patterns of environmentally-induced variation in secondary metabolism.     

苏打盐碱土地区水田水盐运移模拟与预测研究

井灌种稻虽然是近年来松嫩平原西部土地苏打盐碱化治理的有效途径,但苏打盐碱地种稻改良对土壤盐分状况的长期影响,却缺乏定量化评价。作者选择该区代表性地点,通过田间观测与建立模型相结合的方法,对现有种植条件下的水田盐分动态变化进行了模拟和检验。研究发现,经过一定开垦年限土壤剖面平均含盐量下降到1.5g·kg-1左右后,在降水量正常的条件下,土壤盐分已基本达到平衡,不再随着开垦年限增加而进一步下降。相反,如遇干旱年份土壤盐分还会略有增加。需要进一步采取增加排水次数、改善土壤通透性等其它技术措施,才能使苏打盐碱地种稻改良达到更加理想的效果。     

冲天炉烟气除尘

采用湿法除尘,在烟气管道内设置喷嘴,使烟气充分加湿和降温后再进入立式文丘里,旋流析除尘器,消除了ＣＯ爆炸危险,在冲天炉上部烟囟顶端设安全２盖板,以保证生产的正常进行;烟气经湿式除尘后达到排放标准。     

VERIFICATION OF THE RHEA-OROGRAPHIC-PRECIPITATION MODEL1

ABSTRACT: Observed April 1 snowpack accumulations within and near the Gunnison River basin in southwestern Colorado are compared with simulations from the Rhea-orographic-precipitation model to determine if the model simulates reliable magnitudes and temporal and spatial variability in winter precipitation for the basin. Twenty simulations of the Rhea model were performed using‘optimal’parameter sets determined for 10-kilometer (km) grids (10-km by 10-km grid cells) through stochastic calibration. Comparisons of Rhea-model simulations of winter precipitation with April 1 snowpack accumulations at 32 snowcourse stations were performed for the years 1972–1990. For most stations and most years the Rhea model reliably simulates the temporal and spatial variability in April 1 snowpack accumulations. However, in general, the Rhea-model underestimates April 1 snowpack accumulations in the Gunnison River basin area, and the underestimation is greatest for locations that receive the largest amount of snow. A significant portion of the error in Rhea-model simulations is due to the calibration of the Rhea model using gauge-catch precipitation measurements which can be as much as 50 percent below actual snowfall accumulations. Additional error in the Rhea-model simulations is a result of the comparison of gridded precipitation values to observed values measured at points.     

Impact of cadmium and nickel on ion homeostasis in the yeast Schizosaccharomyces pombe

Abstract

Toxicity of heavy metals to living organisms is a worldwide research topic. Although, much has been discovered about cadmium and nickel impact on biological systems, a lot still remains unclear. We used inductively coupled plasma – optical emission spectroscopy to address the question of the effect of two different heavy metals nickel, and cadmium on intracellular ion balance. Increase or decrease of the content of several essential cations including Ca²⁺, Na⁺, K⁺, Mg²⁺, Cu²⁺, Fe³⁺ in the yeast Schizosaccharomyces pombe was determined. Our results revealed that the cell exposure to high nickel and cadmium concentrations led to significant elevation of Ca²⁺, Na⁺, Mg²⁺, Cu²⁺, Fe³⁺ levels in the yeast cell, while the content of K⁺ decreased. Correlation analyses showing in the presence of nickel and cadmium strong positive correlation among each tested element (Ca²⁺, Na⁺, Cu²⁺, Mg²⁺ and Fe³⁺) except for K⁺, demonstrate the significant impact of heavy metal treatment to ion homeostasis of the cell. Our data indicate that acute nickel and cadmium contamination leads to substantial ionome misbalance in yeast.     

PM2.5 chemical source profiles for vehicle exhaust, vegetative burning, geological material, and coal burning in Northwestern Colorado during 1995

PM_2.5 (particles with aerodynamic diameters less than 2.5 μm) chemical source profiles applicable to speciated emissions inventories and receptor model source apportionment are reported for geological material, motor vehicle exhaust, residential coal (RCC) and wood combustion (RWC), forest fires, geothermal hot springs; and coal-fired power generation units from northwestern Colorado during 1995. Fuels and combustion conditions are similar to those of other communities of the inland western US. Coal-fired power station profiles differed substantially between different units using similar coals, with the major difference being lack of selenium in emissions from the only unit that was equipped with a dry limestone sulfur dioxide (SO₂) scrubber. SO₂ abundances relative to fine particle mass emissions in power plant emissions were seven to nine times higher than hydrogen sulfide (H₂S) abundances from geothermal springs, and one to two orders of magnitude higher than SO₂ abundances in RCC emissions, implying that the SO₂ abundance is an important marker for primary particle contributions of non-aged coal-fired power station contributions. The sum of organic and elemental carbon ranged from 1% to 10% of fine particle mass in coal-fired power plant emissions, from 5% to 10% in geological material, >50% in forest fire emissions, >60% in RWC emissions, and >95% in RCC and vehicle exhaust emissions. Water-soluble potassium (K⁺) was most abundant in vegetative burning profiles. K⁺/K ratios ranged from 0.1 in geological material profiles to 0.9 in vegetative burning emissions, confirming previous observations that soluble potassium is a good marker for vegetative burning.     

自然资源资产负债表编制设计及应用Ⅱ：应用

根据作者在《自然资源资产负债表编制设计及应用Ⅰ：设计》中提出的自然资源资产负债表设计方案,论文以湖北省十堰市竹溪县为例,采用统计、市场价格法、替代市场法、意愿评估法等分别编制实物量表和价值量表,在此基础上分析自然资源变化与区域经济发展之间的关系。主要结论如下：1）竹溪县林木和特色资源总量呈逐年上升趋势;水资源中工业用水量逐年减少,工业用水效率不断提高,居民生活用水基本保持不变,城镇公共环境和生态环境用水逐年增加,农业发展受降水等自然条件影响较大,今后应进一步发展现代农业,提高农业用水效率。另外,土地资源有不断向建筑用地转变的趋势,未来竹溪县政府应控制建筑用地面积在合理范围内。2）竹溪县自然资源价值处于一个相对稳定的状态。4种资源中,土地资源价值量最高。人为因素对林木资源价值的影响值均为正值,且绝对值不断增加,人为因素对水资源价值的影响值为负值。3）随着竹溪县GDP增加,自然资源总量保持相对稳定,且每年人为原因对自然资源总价值的影响都是正效应。     

浑河流域沈抚段氮素污染综合溯源研究

通过对浑河流域沈抚段水体样品和主要污染源样品采集及检测,结合氮氧双稳定同位素及SIAR模型,统计分析研究区域氮素污染现状及氮素污染来源,绘制典型污染源的δ15N、δ18O特征分布图并估算其贡献率,准确追踪和定量外来性氮,从而更好地控制进入浑河流域的氮负荷.结果表明,浑河流域沈抚段受排污口、支流输入、工业废水的影响较大,氮素污染严重.研究区域δ15N值在-5.23‰~33.8‰范围内波动,δ18O值变化范围较大,为-4.12‰~61.54‰.工业废水对氮素贡献率为20.6%~96.3%,贡献率最高,其次是生活污水与粪便、化学肥料、土壤,贡献率分布范围分别为0.3%~29.4%、1.2%~33.5%、1.7%~30.1%,大气沉降对氮素贡献率最低,为0~7.2%.考虑大气污染及污废水排放规律能更准确的确定氮素的污染来源.     

城市居民小区双水源中水回用研究初探——以苏州为例

结合苏州本地的实际情况,提出在居民小区中将屋面雨水和优质杂排水作为小区中水回用的双水源,并采用物化法作为核心处理工艺。同时,以苏州城区范围内15个居民小区的水量调查为依据,论证了双水源中水回用工艺的可行性。     

土壤碳淋溶流失研究进展

土壤碳的淋溶流失是指在水的作用下土壤中的碳沿着水文路径转移到水环境的过程。尽管这些流失量有限,却对陆地碳平衡核算具有重要影响。本文在总结了土壤碳淋溶流失研究的重要性、近年来相关领域取得的进展的基础上,指出已有研究的不足有:对土壤无机碳(SIC)的淋溶流失研究薄弱、缺乏野外实地观测、对土地利用变化影响土壤碳淋溶流失的过程与机制认识不足等。今后除了加强以上几个方面的研究外,还要综合利用同位素示踪和在线仪器观测等各种手段,开展"陆地-水生系统连续体"内多界面碳交换的综合研究。