石羊河流域的水化学特征及其地表水与地下水的相互转化

通过分析石羊河流域地表水与地下水的水化学特征,可以了解石羊河流域地表水与地下水的相互转化关系。研究结果表明:(1)武威盆地,在山前地带,出山河水入渗转化为地下水;溢出带地下水以泉的形式转化为地表水;进入细土平原后,河水又补给地下水;在农灌区引河水又通过田间入渗反补地下水。(2)民勤盆地,地下水主要通过引水灌溉和河水补给。     

鄂尔多斯盆地南区环河组地下水水岩作用研究

文中以揭示鄂尔多斯盆地南区白垩系环河组地下水水化学场的形成机理为主要研究目的。在了解鄂尔多斯盆地水文地质条件的基础上,分析了环河组地下水水化学演化特征,应用Phreeqc软件对其进行了水-岩作用的地球化学模拟,定量分析研究了该区地下水的演化过程、形成机理,并进一步分析了南区环河组地下水的补、径、排关系。得出结论为:在水流模拟路径上主要发生了石膏、岩盐、斜长石、钾云母或钾长石的溶解反应和阳离子交替吸附作用,导致地下水的TDS不断增大;其间,受总排泄带位置及东西两侧径流的影响,使水化学演化方向、径流方向产生朝向总排泄带的"向心"偏转,因此,环河组大体上以马莲河入泾河汇入口附近为中心,形成半个向心椭圆状的地下水流动系统。该结论对盆地南区地下水流动系统的划分、边界界定,具有特殊意义。     

陇东盆地白垩系地下水运移研究

陇东盆地气候干旱、降雨稀少,盆地内分布着复杂的地下水含水层,如何有效的评价地下水资源量,怎样合理的开发利用地下水资源成为亟待解决的问题。因此,以白垩系环河组地下水为例,在研究区沿泾河和马莲河共采集水化学样25组,同位素样30组,通过对比分析地下水与地表水水化学样和同位素样的测试结果,来探讨陇东盆地白垩系地下水的控制因素和运移规律。陇东盆地白垩系地下水水化学、同位素特征表明:地下水源于大气降水,向斜两翼为现代降水,向斜核部多为古地质历史时期大气降水;地下水从东西两翼顺层汇集到天环向斜核部,在盆地中部地区河流下游地段排泄于河流或流出盆地;盆地西翼地下水径流交替较东翼快。受陇东盆地地层结构的影响,白垩系地下水向斜核部运移缓慢。     

基于多元统计方法的张掖盆地地下水化学特征分析

为研究张掖盆地的地下水化学特征,对研究区56组水样的9项指标综合运用描述性分析、因子分析和聚类分析的方法进行系统分析.结果表明:张掖盆地的水化学类型沿地下水的补径排路径呈现出明显的水文地球化学分带特征.影响研究区水化学特征的主要因素是以Cl-、SO42-、Na+、TDS、Mg2+、总硬度为主要载荷变量的蒸发浓缩作用,贡献率高达58.922％;其次是以Ca2+和HCO3-为主要载荷变量的补给溶滤作用,贡献率为25.162％.Q型聚类分析大致划分了地下水的补给径流区和排泄区,体现了不同区域的水化学类型的差异性.     

浑善达克沙地东部地区天然水体的水化学组成及其控制因素

浑善达克沙地东部地区位于内蒙古高原,其天然水体为淡水。利用原始型Durov三线图对其天然水体进行水化学分类,结果表明,地表水水化学类型属于碳酸氢盐组,而地下水属于碳酸氢盐组、混合组和硫酸盐组多种类型。天然水体样品在Gibbs图中的分布表明,岩性控制是形成该地区天然水体水化学组成的主要因素,这种情况不同于我国西部和中部沙漠由于蒸发强烈而受控于蒸发-结晶作用的天然水体。天然水体的离子比例关系表明,地下水中蒸发盐岩和硅酸盐岩的风化程度较高,而碳酸盐岩风化程度低,这可能是由于地下水的水-岩作用时间长、二氧化碳供给不充分引起的;相反,由于水-岩作用时间短、二氧化碳供给充分,地表水中蒸发盐岩和硅酸盐岩的风化程度较低,而碳酸盐岩风化程度高。     

黄河三角洲地区地表水化学特征及其主要影响因素

黄河三角洲处于海陆交错带,开展地表水化学特征及其影响因素研究,对于认识水化学演化和水体保护具有重要意义。2015年对主要地表水进行样品采集、现场测试和室内分析。结论如下:水体均为碱性,地表水化学空间变异明显,黄河水到近海水体表现为从淡水-微咸水-咸水-卤水的过渡;对照地表水环境质量标准,超标参数为总磷、硝态氮、氯离子和硫酸盐。综合多元统计、Gibbs图及离子关系分析,得出水化学成分主要受自然因素影响,其次为人类活动因素。前者包括水岩相互作用(碳酸盐、方解石和盐岩的溶解)、蒸发结晶和海水入侵混合作用;后者包括生活污水、采油、炼化废水因素以及氨氮硝化作用,导致有机物及氮磷含量升高,需对后者的污染引起足够的重视。     

甘肃梨园河流域地下水来源及其水化学特征

通过分析水化学与氢氧稳定同位素的关系,研究梨园河流域地下水的补给机理和水化学演化规律。地下水总溶解固体（TDS）自西南向东北递增,最大值为1 258 mg/L。沿流程方向,深层地下水的水化学类型由Ca-HCO₃→Ca-Mg-HCO₃、Mg-SO₄→Na-SO₄型。浅层地下水的水化学类型由Ca-HCO₃→Mg-HCO₃-SO₄→Mg-SO₄型。地表水的水化学类型无分异,主要为Ca-HCO₃型。深层和浅层地下水沿途均发生了水岩融滤作用。Na⁺含量沿程增大,一是地下水中Ca²⁺与岩石中Na⁺发生阳离子交换作用,二是硅酸盐矿物的风化作用产生Na+。Phreeqc软件模拟显示,深层地下水中方解石先沉淀后溶解;CO₂、石膏、白云石和岩盐溶解。浅层地下水中,方解石由不饱和逐渐变为饱和;石膏、岩盐一直溶解。地下水的δ²H和δ¹⁸O值大部分位于大气降水线上方,反应了山区现代降水或雪冰融水通过出山地表径流补给,交替更新快,且深层地下水向上补给浅层地下水和地表水。地表、地下水相互转化是该区水循环的主要特征。     

沙漠腹地达理雅博依绿洲浅层地下水水化学特征分析

为了评价塔克拉玛干沙漠腹地达理雅博依绿洲地下水水化学特征与演化规律及对当地生态环境的影响。在研究区的生态井位观测点采集了19组地下水样品进行检测。综合运用数理统计、相关性分析、Piper三线图、Gibbs模型、Schoeller图和离子比等方法,分析地下水水化学特征和克里雅河尾闾绿洲的水化学演化规律。研究表明:研究区地下水阳离子以Na⁺、Mg⁺离子为主,阴离子以Cl^-、SO₄^2-,为主,Mg⁺、Cl^-、SO₄^2-表现为强变异性,K⁺、Ca⁺、Na⁺、HCO-3表现为中等变异;TDS介于1000mg/L-18620mg/L范围内,平均值为4366.408mg/L,矿化度较高;水化学类型以Cl^--Na⁺为主;地下水样品主要分布于Gibbs图的右上部分,表明研究区地下水主要受蒸发浓缩作用控制,岩石风化和大气降水影响较小;主要离子比表明碳酸盐、蒸发岩和硅酸盐是离子的主要来源,且处于沙漠腹地的独特地理因素,地下水中的离子交换作用较弱。     

天山北麓中段地下水水化学特征及其形成作用

本文通过分析天山北麓中段地下水水化学特征,并对比潜水和承压水水化学特征的异同点,得出结论:(1)地下水化学场受到地质地貌的控制作用,自南向北呈现明显的水平分带性。(2)山前冲洪积扇区,潜水和承压水联系密切,水质好,是城市集中供水水源地的良好选择。(3)细土平原区,潜水沿河道两侧分布着一定宽度的淡水带,反映在一定程度上接受河水的补给。(4)承压水是细土平原区工农业用水的首要选择;沙漠边缘和乌鲁木齐城镇区地下水水质差,不宜利用,可采用地表水或外流域调水。(5)地下水水化学特征的形成是受溶滤作用、蒸发作用和脱硫酸作用以及阳离子交换作用等共同作用的结果。     

黄河三角洲水盐演化及补给来源 ——基于水化学与同位素分析

对河口地区地表水和浅层地下水采样调查,结合离子全组分和稳定同位素证据,分析了研究区水化学特征与各水体补给来源,探讨了长期引黄灌溉对区域水循环、地表水-地下水交换的影响。结果显示：(1)河口区地表水与浅层地下水都具有较高的矿化度,浅层地下水与地表水平均矿化度分别为27.96、23.17 g·L-1,地表水和浅层地下水中阳离子Mg²⁺、Na⁺、K⁺,阴离子Cl^-、SO^2-₄是与总溶解固体(TDS)显著相关的主要离子成分;(2)浅层地下水水化学类型为Cl-Na·K,是典型的海水混合或者卤水;地表水由于工、农业和城市污染,水化学类型向Cl·SO₄-Na·K·Ca变化,水化学类型变化复杂;(3) 地表水水体的盐分补给来源于海水混合以及城市及农业污染,而浅层地下水的输入则来自海水入侵以及降水、地表水的下渗补给;(4) 生态调水后地表水对浅层地下水的补给高值区主要分布在农田和近海湿地,补给比例48%~81%,而海岸滩涂带地下水的补给比例最低,这可能与海岸含水层渗透系数相对农田和湿地较小有关。     

重视有害蚜虫研究,确保作物安全

<正>蚜虫隶属半翅目蚜虫总科,是世界上分布最广的微小昆虫之一。世界已知4 700余种,中国分布约1 100种[1-2]。蚜虫种类多、繁殖快、世代重叠,还存在孤雌生殖与两性生殖世代交替等独特生物学现象。许多蚜虫种类是非常重要的农作物害虫,其刺吸式口器可吸食植物汁液,造成植物生长不良,其唾液也对植物有毒害作用[3-4]。受蚜虫为害的植物具有多种不同症状,如生长率降低、产生叶斑、泛黄、发     

高原人体生理适应学理论在进藏旅游中的应用

青藏铁路的贯通运行,带来了国内外进藏旅游热.然而,青藏高原毕竟是世界屋脊,高海拔带来的低氧及其引发的高原疾病依然威胁着游客的身体健康.健康高原旅行是当前游客进藏旅游的基本前提,通过综合国内外高原医学工作者对高原医学生理学的研究成果,提出阶梯进藏旅游的方法.旨在对越来越多的短期赴西藏高原旅行的人群以正确的健康指导,从而减...     

稻瘟病菌对三环唑抗药性测定方法的建立

研究了稻瘟病菌对三环唑抗药性的测定方法,确定了保绿培养基的成分,建立了抗药性测定的标准化模型。4叶I心期将稻苗在三环唑系列浓度药液中浸根处理36 h,剪取稻苗叶段插于100 μg/mL苯并咪唑+0.5％水琼脂保绿培养基上,用孢子含量为10⁵个/mL的稻瘟病菌孢子悬浮液喷雾接种,保湿培养8 d后调查结果,计算EC₅₀值。该测定方法与小苗测定相比较结果更加稳定且灵敏度高,重复性好。     

白刺花(Sophoraviciifolia)适应土壤干旱的生理学机制

用盆栽的方法人工控制土壤干旱条件,研究白刺花天然实生幼苗适应土壤干旱的生理学机制。结果表明:随土壤含水量的减少,白刺花叶水势在胁迫前期下降缓慢,随胁迫时间的延长,水势大幅度下降。白刺花通过在叶片内积累大量渗透保护性物质可溶性糖和K ,增加细胞的保水力,维持细胞生长所需膨压。白刺花游离脯氨酸含量变化与水分关系不大,可溶性蛋白质含量随土壤含水量减少而下降,可能是水分胁迫下受伤害的表现。随土壤水分含量的减少,白刺花SOD的活性明显升高,POD活性不高但随胁迫时间延长其活性较稳定,CAT活性下降但幅度不大,且CAT活性变化趋势与POD活性相反,说明三个保护酶能够相互配合协同作用,降低膜脂过氧化程度,减少水分胁迫造成的伤害,提高质膜稳定性,维持细胞膜的完整性,表现出很强的抗旱适应性。     

Heritability of Ulmus minor resistance to Dutch elm disease and its relationship to vessel size,but not to xylem vulnerability to drought

Dutch elm disease (DED) is a vascular wilt disease that causes the occlusion and cavitation of xylem vessels. Therefore, it is hypothesized that those elms that are less vulnerable to cavitation by drought might be more resistant to DED. To test this hypothesis, the relationship between xylem vulnerability to cavitation and susceptibility to DED was examined in progenies of crosses between susceptible and resistant individuals of Ulmus minor. Hydraulic conductivity and xylem vulnerability curves were evaluated and anatomical features such as vessel size, length and grouping were measured. Next, elms were inoculated with Ophiostoma novo‐ulmi, the cause of DED, and pre‐dawn and midday water potentials, stomatal conductance and wilting percentages were assessed. Progenies of R × R crosses showed significantly lower mean wilting percentages (30–50%) than the progeny of S × S crosses (75%). Fifty percent conductivity loss was reached at c. ?1 MPa, pointing out a high vulnerability of this species to drought‐induced cavitation. Crown wilting percentage as a result of inoculation and xylem vulnerability to cavitation by water stress did not show any significant correlation. Nevertheless, significant differences in theoretical hydraulic conductivity and vessel size parameters (diameter, length and size distributions) were found among the tested progenies. Susceptible trees had significantly wider and longer vessels. Xylem structure of resistant elms seems to restrict pathogen spread rather than prevent cavitation.     

A grower-friendly method to transfer predacious mites to commercial orchards

The establishment of predacious mites in commercial orchards may be accelerated by the transfer of pruned wood in winter and summer from donor orchards to release orchards. Following winter pruning, 3-year-old and older wood is collected and transported as soon as possible in bundles to a release orchard for distribution. If the release orchard is composed of dwarf trees, then one or two bundles of 5 kg each are placed vertically at the base of the trunk of every tree in the block (0.5 to 1 ha); if the trees are of standard size, then four or five bundles used. Following summer pruning, annual shoots and suckers are distributed immediately in a release orchard composed of dwarf trees by placing 12–15 branches on the foliage of fruit-bearing branches; if the release orchard is composed of standard trees, then 50 branches are used. The pruned wood should have 20–25 leaves and not less than one predator per leaf. The release orchard should have a light infestation (two or three mites per leaf) of pest tetranychids. These phytophagous mites would serve as food and help establish the predators. The release orchard grower should develop a pest management program based on the same groups of pesticides used in the donor orchard. http://www.phytoparasitica.org posting Aug. 31, 2005.     

Contribution of Fimbrial and Afimbrial Adhesins of Xylella fastidiosa to Attachment to Surfaces and Virulence to Grape

ABSTRACT The role of fimbrial and afimbrial adhesins of Xylella fastidiosa in biofilm formation was assessed by visualization of cell aggregates of mutant strains after incubation on glass surfaces. FimA- or FimF- fimbrial mutants adhered as solitary cells at a slightly lesser frequency to glass surfaces than the parental strain; however, cell aggregates were not formed, unlike the wild-type strain. Conversely, whereas the XadA- and HxfB- nonfimbrial mutants also exhibited a much lower frequency of adherence to glass surfaces than the wild-type strain, most of the cells retained on the surfaces were in cell aggregates of different sizes, much like that of the parental strain. Neither fimbrial or afimbrial mutants formed a mature biofilm on the sides of flasks of broth cultures, unlike the dense biofilm formed by the wild-type strain. Although FimA- and FimF- mutants did not form cell aggregates on glass surfaces when incubated as individual strains, aggregates of a FimA- or FimF- mutant were observed when co-incubated with either a XadA- mutant or HxfB- mutant, respectively. These results are consistent with a model in which the fimbrial adhesins FimA and FimF are involved preferentially in cell-to-cell aggregate formation whereas the afimbrial adhesions XadA and HxfB preferentially contribute to initial cell binding to surfaces, whereupon further cell aggregation can occur. In each of five separate experiments, FimA, FimF, XadA, and HxfB mutants of X. fastidiosa all were less virulent to grape than the corresponding wild-type strain. Fimbrial and afimbrial mutants might produce a reduced biofilm within vessels of grape and, hence, be deficient in various cell-density-dependent traits required for movement through the plant and, thus, virulence.     

Note to chew on: insect damage to musical instruments

Insects have a diverse range of ecologies that leaves many pre‐adapted to exploiting manufactured products as food sources, including musical instruments. To review what is known and to make recommendations for preventing and managing insect damage to musical instruments, we conducted a systematic search and a narrative review of the area. Of 339 papers, only eight peer‐reviewed publications met the inclusion criteria, and all were on xylophagous insects causing damage to wooden instruments. To supplement this material, we report a case of damage to the key pads (composed of felt enclosed in fish buoyancy bladder skin) of a clarinet by carpet beetles (Anthrenus verbasci (Dermestidae)), the first reported case of non‐woody damage and the first instance of insect damage rendering an instrument unplayable. To avoid such damage, regular inspection of instruments is recommended, and rapid treatment of any insect infestations in the immediate environment that could extend to affecting stored instruments. Instruments themselves can be extremely expensive, and if insects are still present these should only be treated by an expert; instrument cases can be more easily dealt with by heat treatment (black plastic bag in the sun) or application of a residual insecticide. © 2020 Society of Chemical Industry