Ca^2＋参与乙烯消减NaCl对苜蓿种子萌发的抑制

外源乙烯能消减ＮａＣｌ对苜蓿种子萌发的抑制，乙烯的这种作用对包被（种皮和胚乳）具有依赖性；胚与包被处于分离时，外源乙烯的消减作用消失；加回包被后，外源乙烯的作用恢复．分析表明，包被中存在某种易溶于水的、热稳定的小分子物质为乙烯作用所必需；当包被存在时，ＥＤＴＡ及ＥＧＴＡ都能减少乙烯的作用．分析显示：包被中Ｃａ２＋含量较大，且Ｃａ２＋能代替包被作用；无包被存在时，Ｃａ２＋对外源乙烯的有效性具决定作用，表明包被中的有效物质可能是Ｃａ２＋，乙烯的作用依赖于Ｃａ２＋．     

用棉籽壳制乙酰丙酸及活性炭

棉籽壳经加酸加热水解,制得乙酰丙酸,收率为16．2％;残渣经硫酸炭化磺化,制得木素活性炭,收率为81．2％,脱色性能优于国家标准GB／T12496．22－90）。     

The influence of south Foehn on the ozone distribution in the Alpine Rhine valley—results from the MAP field phase

During the Mesoscale Alpine Programme (MAP) special observation period (SOP) between 7 September and 15 November 1999, ground-based and airborne measurements have been conducted in the Rhine valley south of the Lake of Constance to investigate the unstationary aspects of Foehn and related phenomena, like the impact of Foehn on the ozone concentrations in the valley. Foehn events occurred with above-average frequency and high diversity. Foehn induced ozone peaks in October and November are found to be much lower than the September Foehn case of the period. An inversion layer in the lake area with ozone concentrations below 10 ppb often shields the monitoring stations from the Foehn air aloft. Trajectory calculations for the Foehn period between 19 and 24 October 1999 reveal that the Foehn air originated from below 1 to 1.5 km above the Po Basin and the Mediterranean Sea. Tethered balloon soundings in the source area south of the Alps, ozone measurements at the mountain station Jungfraujoch (3580 m a.s.l.) and airborne measurements across the Alpine crests reveal that the ozone levels found in the Foehn air correspond to the concentrations just above the mixing height in the Po Basin and are transported across the Alpine crest within the lowest flow layer.     

Concentration levels of disinfection by-products in 14 swimming pools of China

Swimming has become a popular exercising and recreational activity in China but little is known about the disinfection by-products (DBPs) concentration levels in the pools. This study was conducted as a survey of the DBPs in China swimming pools, and to establish the correlations between the DBP concentrations and the pool water quality parameters. A total of 14 public indoor and outdoor pools in Beijing were included in the survey. Results showed that the median concentrations for total trihalomethanes (TTHM), nine haloacetic acids (HAA9), chloral hydrate (CH), four haloacetonitriles (HAN4), 1,1-dichloropropanone, 1,1,1-trichloropropanone and trichloronitromethane were 33.8, 109.1, 30.1, 3.2, 0.3, 0.6 µg∙L⁻¹ and below detection limit, respectively. The TTHM and HAA9 levels were in the same magnitude of that in many regions of the world. The levels of CH and nitrogenous DBPs were greatly higher than and were comparable to that in typical drinking water, respectively. Disinfection by chlorine dioxide or trichloroisocyanuric acid could substantially lower the DBP levels. The outdoor pools had higher TTHM and HAA9 levels, but lower trihaloacetic acids (THAA) levels than the indoor pools. The TTHM and HAA9 concentrations could be moderately correlated with the free chlorine and total chlorine residuals but not with the total organic carbon (TOC) contents. When the DBP concentration levels from other survey studies were also included for statistical analysis, a good correlation could be established between the TTHM levels and the TOC concentration. The influence of chlorine residual on DBP levels could also be significant.     

轮叶马先蒿群落土壤种子库特征研究

轮叶马先蒿种子小,数量多,已成为巴音布鲁克草原的入侵种。为有效遏制其入侵,论文通过野外植被调查和室内试验分析,研究了轮叶马先蒿土壤种子库的分布状况及其与生境的关系。结果表明:①土壤含水量是影响轮叶马先蒿种子水平分布的主要因素,土壤种子数量垂直分布表现为枯落物层>腐殖质层>心土层,各层土壤种子数量差异性显著;②轮叶马先蒿土壤种子库的大小与轮叶马先蒿的密度、盖度呈显著正相关,与其他地上植被关系不密切;③土壤含水量是轮叶马先蒿生长生殖的限制因素,轮叶马先蒿产生的花苞数以及产生的种子数量在土壤含水量为0.25时达到最大值,当土壤含水量超过轮叶马先蒿的耐受限度,就不会产生种子,5月下旬和6月上旬是轮叶马先蒿种子萌发的最佳时期;④土壤中有机质含量是轮叶马先蒿生长和繁殖过程中的另一个主要影响因素。     

铜与草甘膦复合污染对小麦种子发芽与根伸长的抑制作用

污染物的交互作用及其生态毒理效应已成为环境科学研究的重要方向.论文以小麦种子为供试作物,研究了重金属铜(Cu2+)与除草剂草甘膦复合污染对其发芽率以及发芽后的根长、芽长的影响,以表征Cu与草甘膦复合污染的生态毒性.研究结果表明,在实验浓度下,Cu2+单一污染对小麦发芽率没有明显的影响,对根伸长和芽长的抑制显著;而草甘膦单一污染对小麦发芽、根伸长和芽长均有明显的抑制效应.当Cu2+与草甘膦复合污染时,Cu2+的存在在一定程度上减弱了草甘膦对小麦发芽及芽长的抑制作用;而在根伸长实验中,在低草甘膦浓度条件下,Cu2+的存在在一定程度上增加了草甘膦对根伸长的抑制作用;在较高草甘膦浓度条件下,Cu2+的存在则降低了草甘膦对根伸长的抑制作用.Cu2+的存在减轻草甘膦对小麦毒性的可能原因是:草甘膦与Cu2+络合形成了毒性较小的稳定络合物,使草甘膦毒性降低或失去活性.     

La(NO3)3浸种对盐碱胁迫下红小豆幼苗生长和抗氧化酶活性的影响

采用添加NaCl和Na2CO3模拟盐胁迫和碱胁迫的水培方式,研究了La(NO3),浸种对盐胁迫和碱胁迫下红小豆幼苗生长和抗氧化酶活性的影响.结果表明:(1)与无胁迫对照组相比,盐碱胁迫明显抑制了红小豆幼苗的生长;在Na+质量浓度相同的情况下,碱胁迫对红小豆幼苗生长的影响明显大于盐胁迫;(2)使用La(NO3)3浸种可缓解盐碱胁迫带来的不良影响,使受胁迫红小豆的株高、叶面积、总根长、总根数、叶绿素、根活力、SOD活性、POD活性及CAT活性增加,并显著降低幼苗MDA含量水平,且表现出在盐碱胁迫下变化幅度高于无胁迫处理的现象;(3)在本试验条件下,30 mg·L-1La(NO3)3浸种具有显著促进红小豆根系及地上部分生长的作用.     

高速公路通道集水净化渗透系统及其水质分析

结合河北省大广高速公路衡大段实体工程,针对路表径流污染物的种类及处理机理,提出了通道集水净化渗透系统的好氧兼氧消化-沉淀-人工材料吸附-土壤渗滤一元化的复合工艺,该工艺主要采用蛭石作为过滤材料,将路表径流的污染物控制在饮用水水质标准范围内,不仅有效地解决了通道积水问题,还使得地下水得到补充。     

Parameterization of the roughness length over the sea in forced and free convection

In the condition of free convection, the Charnock relation is inadequate. In this paper we extend the Charnock relation to include the effect of free convection on the roughness length. As a result, the singularity in the Monin–Obukhov similarity theory can be avoided. This paper shows two approaches to derive the roughness length formula in the forced and free convections. The first approach is based on the mixing length theory and the use of the observational data of the vertical velocity variance. We introduce a new vertical velocity scale based on the vertical velocity variance; this velocity variance is well behaved in the atmospheric boundary layer and easy to obtain from field experiments. The second approach is based on the theoretical framework of Sykes et al. (Q R Met Soc, 119: 409–421). From that framework, we develop a theory to obtain the roughness length formula. The results of these two approaches are in agreement with each other. In the past, a multiplication factor associated with free convection was considered to be a constant. This paper shows that this multiplication factor is, in fact, also dependent on the depth of the mixing height. In previous studies, experimental works were often conducted without taking into account the depth of the mixing height. Not taking into account the mixing height in the estimation of the roughness length in free convection would result in an inaccurate estimate of the roughness length and hence the drag coefficient. An erratum to this article can be found at