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1.
大耳白兔动脉血和脑脊液酸碱电解质值及其相互关系   总被引:2,自引:0,他引:2  
30只正常大耳白兔,经股动脉穿刺插管和枕骨下经皮穿刺入枕骨下池,在严格隔绝空气情况下,分别取得动脉血和脑脊液(CSF)标本,用ABL3型血气分析仪及CN644型生化分析仪检测主要酸碱变量及电解质值。经统计学处理结果表明:CSFpHey k^+、Ca^2+、Mg^2+浓度〈动脉血,CSFPCO2及HCO3^-、Cl^-Na^_、H^+〉动脉血。另外,CSFPH与pHa,CSFPCO2与PaCO2、C  相似文献   

2.
心肌细胞内pH调节   总被引:1,自引:0,他引:1  
孙冰  张敏 《生理科学进展》1995,26(3):253-255
心肌细胞具有自身的酸碱缓冲能力,并且通过Na^+/H^+交换蛋白、Na^+/HCO^-3同向转运和乳酸的跨膜运转使H^+外向转运,通过Cl^-/HCO^-3交换使H^+内向转运等途径以维持细胞内生理PH,心肌细胞内Ca^2+浓度受PH变化的影响。  相似文献   

3.
水溶性红曲红色素的制备与表征   总被引:5,自引:0,他引:5  
以碱解法制备水溶性红曲红色素,碱解过程可使红斑素和红曲红素分子中的内酯键找开,生成闳酸盐,提高其亲水性。当反应体系NaOH与红曲色素用量比例为1:13时,碱解过程可在15min内完成。在PH5~6范围同,生成的水溶性红色素扣及光值随PH增大面临略有提高。加热和光照都将影响其稳定性,绝氧则对提高其稳定性无明显影响。在中性条件下,Ca^2+、Mg^2+导致色素溶液沉淀,Sn^2+、Al^2+、F3^3  相似文献   

4.
通过4个土壤深度100个样品14个波长(250、254、260、265、272、280、285、300、340、350、365、400、436和465 nm)土壤溶液吸光度值和土壤碳(可溶性碳DOC、全碳SOC)、土壤氮(可溶性氮DON、全氮SON)的测定,旨在探讨土壤溶液吸光度指示土壤碳氮指标的可行性及土壤深度对其可能影响。结论如下:(1)表层土壤和深层土壤吸光度值均随波长增加而指数下降,但表层土壤吸光度值较高,下降速度较快,较低波长更有利于区分表层和深层土壤溶液吸光度差异;和深层土壤相比,表层0~20 cm土壤SOC、DON和SON与不同波长吸光度有更好的相关性,但DOC与不同波长吸光度的相关性表层和深层差异较小;(2)250~300 nm的8个吸光度值具有高度相关性,它们在分析土壤溶液吸光度变化时具有等效性;基于所有数据的拟合分析发现,低波长(如254 nm)吸光度与土壤SOC、DON和SON相关性最高(R2=0.53~0.59),而更高波长(340 nm及以上)相关性明显降低。但DOC与254、340、365和400 nm吸光度相关性相差不大(R2=0.25~0.33)。这些发现说明,土壤溶液吸光度值,特别是低波长(250~300 nm)可以表征落叶松林土壤碳、氮相关指标的变化,但是需要考虑不同碳氮指标以及不同土层之间的差异。  相似文献   

5.
淋洗与植物作用耦合对盐渍化土壤的改良效应   总被引:2,自引:0,他引:2  
唐让云  曹靖  董放  董利苹  孔晓乐 《生态学报》2015,35(17):5686-5694
以甘肃秦王川引大灌区盐渍化土壤为背景,以当地5种耐盐植物为材料,采用根袋法盆栽试验动态研究了淋洗结合植物种植对盐渍化土壤改良的效应。结果表明:与种前相比,单纯的淋洗作用对土壤pH值影响不大,而淋洗结合植物种植明显降低了土壤pH值,且根际土壤pH值小于非根际土壤的,5种耐盐植物中霸王根际土壤pH值降低幅度最大,达0.6个单位。K+、Ca2+、Na+、Mg2+、Cl-和SO2-4在5种植物根际土壤中均有不同程度的富集,富集程度因物种的不同而不同,随培养时间的延长而呈波动状态。5种供试植物和对照组土壤中的6种主要的可溶性盐分离子随淋洗次数和培养时间的延长呈下降趋势。在培养120d后,单纯淋洗的土壤中K+、Ca2+、Na+、Mg2+、Cl-和SO2-4的含量相比种前平均分别降低了33.3%、26.1%、35.6%、32.5%、35.5%和36.3%,植物吸收带走的上述各离子的含量平均分别占种前的46.2%、8.1%、30.2%、7.2%和21.6%,其中霸王吸收带走的盐分离子最多,而淋洗结合种植植物的土壤中上述各离子的含量与种前相比平均分别降低了67.25%、63.73%、83.8%、67.5%、81.55%和78.46%,由此可见,淋洗结合植物种植的脱盐效果优于单纯淋洗,且土壤中主要的盐分离子Na+、Cl-和SO2-4的含量降低幅度最大,通过计算得出,在Cl-、SO2-4和Na+减少的总量中还有37.73%的Na+、38.22%的Cl-和35.14%的SO2-4的减少量是由植物根系的物理化学作用机制引起的。  相似文献   

6.
碱性盐胁迫下星星草幼苗中几种渗透调节物质的变化   总被引:27,自引:2,他引:25  
阎秀峰  孙国荣 《植物研究》1999,19(3):347-353
模拟松嫩盐碱草地碱化土壤的离子组成配制碱性盐溶液处理星星草(Puccinelliatenuiflora)幼苗,测定了碱性盐胁迫下星星草幼苗地上部分几种渗透调节物质含量的变化,随着碱性协浓度及胁迫天数的增加,Na^+可溶性盐,游离脯氨酸和可淀粉糖的含量逐渐增加,其中游离脯氨酸的变化倍数最大,K^+含量在浓度小于20gL^-1碱性胁迫下随胁迫天数增加而略为减少,在40grL^-1和60gL^-1碱性胁  相似文献   

7.
污染土壤淋洗修复技术研究进展   总被引:22,自引:0,他引:22  
土壤淋洗修复技术是一种行之有效的污染土壤治理技术,适合于快速修复受高浓度重金属和有机物污染土壤与沉积物。本文综述了土壤淋洗修复技术的特点、技术流程、土壤淋洗剂的研究与应用进展,指出异位土壤淋洗修复技术因修复效果稳定,易于实现系统控制和废弃物减量化等优点而具有更广阔的应用前景,天然螯合剂和生物表面活性剂等环境友好型淋洗剂正逐渐取代人工螯合剂和化学表面活性剂成为土壤淋洗剂研究的主流方向,而现代超分子化学的引入和发展有可能对复合污染土壤的高效淋洗修复研究产生新的影响。  相似文献   

8.
本文观察到易卒中自发性高血压接受高钙(3%)饮食6周后抑制了血压上升,胞浆游离钙浓度降低和血浆钙高,细胞内PH也产生改变,接近正常对照的WDY大鼠。本文对细胞内PH,Na^+-H^+交换,胞浆游离钙浓度与血压的关系进行了讨论。  相似文献   

9.
土壤可溶性碳氮在森林土壤碳循环和养分循环中起到重要作用,因其对气候变化高度敏感且可被微生物直接利用.本研究通过在2年生杉木人工林内设置隔离50%降雨处理(P)、增温5 ℃+隔离50%降雨处理(WP),利用张力测渗计野外原位收集土壤溶液,研究降雨和温度变化对不同深度土壤可溶性碳氮浓度的影响.结果表明: 降雨和温度变化没有改变土壤可溶性有机碳(DOC)浓度的季节变化,土壤溶液DOC浓度在10月最高.降雨和温度变化增加了不同土层土壤溶液DOC浓度,60 cm处增加量最大,与对照相比,P和WP处理土壤溶液DOC浓度的增加幅度分别为30.4%~88.7%和32.8%~137.6%,10 月的差异值最大,对照土壤溶液DOC浓度随土壤深度增加而降低,但降雨和温度变化后各土层间土壤溶液DOC浓度没有显著差异.WP处理土壤溶液NO3--N浓度大幅增加,增加幅度为221.1%~931.0%.在未来全球变化背景下,亚热带地区降雨减少将增加土壤通透性和细根向深层土壤的生长,促进土壤微生物活性和有机质分解,可能增加本地区土壤有机碳氮淋溶流失,而温度增高将加剧碳氮流失风险.  相似文献   

10.
为探究氮沉降对亚热带杉木人工幼林土壤溶液可溶性有机物质(DOM)浓度及光谱学特征的影响,采用负压法,对0~15和15~30 cm土层土壤溶液DOM进行了2年的动态监测及光谱学特征研究.结果表明:氮沉降显著减少了各土层土壤溶液可溶性有机碳(DOC)浓度,增加了芳香化指数(AI)及腐殖化指数(HIX),但对可溶性有机氮(DON)无显著影响.土壤溶液DOM浓度存在明显的季节变动,夏秋季显著高于春冬季.傅里叶红外光谱结果表明,森林土壤溶液DOM在6个区域的相似位置存在吸收峰,其中1145~1149 cm-1的吸收峰最强.三维荧光光谱表明,DOM主要以类蛋白质物质(Ex/Em=230 nm/300 nm)和微生物降解产物(Ex/Em=275 nm/300 nm)为主,施氮使0~15 cm土层类蛋白质物质减少.氮沉降可能主要是通过降低土壤pH、抑制土壤碳矿化和刺激植物生长等途径显著抑制土壤溶液DOC浓度,而表层被抑制的DOC成分以类蛋白质物质和羧酸盐物质为主.氮沉降短期可能有利于土壤肥力的储存,但随着氮沉降量的积累,土壤中营养物质将难以得到有效利用.  相似文献   

11.
High levels of aluminium in the soil solution of forest soils cause stress to forest trees. Within the soil profile, pH and aluminium concentration in the soil solution vary considerably with soil depth. pH strongly influences the speciation of A1 in solution, and is a factor when considering toxicity of A1 to roots. Norway spruce ( Picea abies [L.] Karst.) seedlings were grown for 7 weeks in nutrient solutions at pH 3.2, 4.0 or 5.0 containing 0, 100 or 400 µ M A1. At the end of this period, seedling growth, the cation exchange capacity of the roots and the amount of exchangeable Ca and Mg in roots were determined. A1 concentrations in whole roots, root segments, and in needles were measured. Using X‐ray microanalysis, the concentrations of Al, Ca, Mg and P were determined in cortical cell walls. We wanted to test the hypotheses that (1) the amount of Al bound to cation exchange sites can be used as a marker for Al toxicity and (2) the Mg concentration of needles is controlled by the amount of Mg bound to cation exchange sites. Low pH reduced the inhibition of Al on root growth and shoot length. Both low pH and Al lowered the concentration of Ca and Mg in needles. Al concentrations in the roots decreased as the pH decreased. In the roots, Al displaced Mg and Ca from binding sites at the root cortical cell walls. A comparison of the effects of Al at the different pH values on root growth and Mg concentration in the needles, suggests that, at pH 5.0, an Al fraction in the apoplast inhibits root growth, but does not affect Mg uptake. This fraction of Al is not available for transport to the shoots. In contrast, Mg uptake is strongly affected by Al at pH 3.2, although only very low levels of Al were detected in the roots. Thus, Al accumulation in the apoplast is a positive marker for Al effects on root growth, but not Mg uptake. The Mg concentration of needles is not controlled by the amount of Mg bound to cation exchange sites.  相似文献   

12.
To focus conservation efforts into forest areas with high biodiversity, more information is needed about soil-vegetation dependencies in Finnish Lapland. We studied understory vegetation and soil variables along a transect across a felsic?Cmafic lithological sequence in central Finnish Lapland. At 119 northern boreal forest sites, coverages of understory vegetation, several mineral soil chemical elements, soil electrical conductivity, pH, and dielectric permittivity, as a measure of soil volumetric water content, were measured. We found that soil Ca concentration and Ca:Al ratio were the main variables determining vegetation composition and diversity. Ca-rich soils were characterised by high electrical conductivity, pH, and Mg concentration, and by low concentration of Al, S, Zn, and low C:N ratio. Soil Ca concentration is a diagnostic measure of plant diversity as concentration higher than 100 mg kg?1 resulted in a considerable increase in plant diversity. Sites with Ca concentration this high were rare, and probably important in maintaining high biodiversity. The median soil Ca:Al ratio was only 0.02, suggesting, according to general theory, a considerable risk for aluminium stress. We found Geranium sylvaticum and Rubus saxatilis to be good indicators for Ca-rich regimes and high plant diversity.  相似文献   

13.
Abstract. A large number of plots (306) were sampled for floristic data and variables of soil nutrient availability in a wide range of forest conditions in the Vosges mountains (NE France). Half of the data were used to model species presence/absence as a function of nutritional variables using two numerical methods: parametric logistic regression and non‐parametric Kernel estimation. Species responses were established for calcium, aluminium, Ca : Al ratio, base saturation, pH and C:N measured in the upper soil horizon. The other half were used to predict these variables with vegetation with three approaches: maximum likelihood, indicator values and ecological groups. More than 80% of the 122 studied species showed a significant response to one or more nutrition factors. Species often had optima for maxima or minima of the studied values. For each variable, species were more frequent in conditions with good nutrition and/or low toxicity: maximum values were most frequent for Ca, Ca: Al, base saturation, pH and minimum values were most frequent for Al and C:N. For all variables, optima estimated by logistic regression were well correlated with those estimated by kernel estimation: R2 > 0.9. Mean differences between measured values and predictions by vegetation were ca. 2.6 meq for Ca, 1.2 for log Ca, 3.1 meq for Al, 1.8 for log Al, 30 for Ca:Al, 2.1 for log Ca:Al, 0.21 for base saturation, 0.7 for pH and 5.7 for C:N. The quality of prediction as measured by R2 between predicted and measured values varied from 0.60 to 0.14. The quality of prediction decreases from soil base saturation to aluminium according to the next order: base saturation > log Ca : Al > log Ca > Ca > C :N > pH > log Al > Al > Ca :Al. Maximum likelihood and ecological groups methods of prediction were more efficient than the indicator values method.  相似文献   

14.
Jörg Brunet 《Plant and Soil》1994,161(2):157-166
The influence of base cation concentrations on pH and aluminium sensitivity of the woodland grasses Bromus benekenii and Hordelymus europaeus was studied in flowing solution culture experiments. Plants were exposed to low pH (3.9, experiment 1) and Al concentrations of 19 and 37 M (experiment 2) at two base cation (Ca+Mg+K) levels, all within the ranges measured in natural forest soil solutions. Elevated base cation concentrations ameliorated both H and Al toxicity, as indicated by increased root and shoot growth. In the third experiment, interactions between pH (4.3 and 4.0) and Al (0 and 19 M) were investigated. It was shown that the combined toxicity effects of H and Al were not greater than the separate H or Al effects. Tissue concentrations of base cations and Al increased with increasing concentrations in the solution, but were also influenced by the base cation : Al ratio. Relating the experimental evidence with the composition of forest soil solutions suggests an important role of soil pH and Al in controlling the distribution of the two species. Growth conditions also differ at various soil depths. Concentrations of free cationic Al were higher and base cation concentrations lower at 5–10 cm than at 0–5 cm soil depth. Increasing base cation concentrations may protect roots from both H and Al injury during periods of drought when concentrations of most elements increase in the soil solution, whereas molar ratios between base cations, H and Al remain unchanged.  相似文献   

15.
Chen  Zueng-Sang  Hsieh  Chang-Fu  Jiang  Feei-Yu  Hsieh  Tsung-Hsin  Sun  I-Fang 《Plant Ecology》1997,132(2):229-241
Soil chemical properties for a subtropical rain forest in the Nanjenshan Reserve, southern Taiwan, were examined to determine soil-landscape and soil-vegetation relationships. Soil sampling sites were separated into four groups based on landscape features and exposure to the prevailing northeasterly monsoon winds. Corresponding vegetation types were delimited along the first DCA axis. The forest showed a drastic change both in structure and floristic composition along the wind-stress gradient. Redundancy analysis (RDA) showed that both topographic variables and vegetation types were needed to explain the variation in soil data. Soil properties that differed significantly among landforms were pH, available N, CEC, exchangeable Al, K, Ca and Mg. Levels of pH, exchangeable Ca and Mg increased in a downslope direction, and exchangeable Al tended to be higher in the upper slope soils. These trends pointed to the importance of slope processes in redistribution of soil minerals. The main differences in soil properties attributed to the influence of the occupying vegetation were apparently aspect dependent. The contents of available N, exchangeable K, and CEC in the 0–40 cm depth of soils under windward low-stature (mostly sclerophyllous) forest were consistently lower compared to those under the leeward forest. For a given catena, however, soil variability associated with vegetation differences seemed to be confounded by the slope processes.  相似文献   

16.
Honeylocust (Gleditsia triancanthos L.) root growth response to varying levels of Al and Ca in soil solutions was examined in two horizons each of two forest soils. With results from all four horizons combined, multiple regression analysis indicated that both Ca and Al were significant (p<0.01) factors affecting root elongation, branching and biomass production. Over a wide range of Al and Ca concentrations in soil solutions from four different soil horizons, the Ca:Al ratio was a significantly better predictor of honeylocust root response to acid soils than Al or Ca alone.  相似文献   

17.
唐鸿寿 《生态学报》1999,19(2):200-205
赤黄壤酸化后,化学性质和物理性质均发生明显变化,pH值下降,并淋溶出大量对植物生长有害的Al离子。土壤团粒结构受到破坏,土壤的保水性增加,通气性变差,粘度增加。油松种子在酸化后的赤黄壤中萌发率下降,其直接原因是土中Al离子大量增加,间接原因是土壤pH值下降(pH≥3.5)。部分油松种子萌发后,因土壤粘度增加,针叶被粘在土内,最终导致幼苗死亡。赤黄壤粘度增加是由于土壤酸化后,粒径普遍变小,尤其是小于250μm的小团粒数量增加造成的。  相似文献   

18.
In this review, I summarized the results obtained from experimental studies on the ecophysiological responses of Japanese forest tree species to O3, simulated acid rain and soil acidification. Based on the studies conducted in Japan, exposure to ambient levels of O3 below 100 nl·l−1 (ppb) for several months is sufficient to inhibit dry matter production and net photosynthesis of sensitive Japanese forest tree species such as Siebold's beech and Japanese zelkova. On the other hand, exposure to simulated acid rain with a pH of 4.0 or above for several months cannot induce any adverse effects on dry matter production and physiological functions of Japanese forest tree species. However, when the pH of simulated rain or fog is lowered below 4.0, negative effects appear on dry matter production and physiological functions such as transpiration in several sensitive Japanese forest tree species such as Japanese fir and Nikko fir. Based on limited information, it may be concluded that (1) Al dissolved into soil solution is the most important limiting factor for dry matter production, physiological functions and nutrient status of Japanese forest tree species grown in acidic soil, (2) the (Ca+Mg+K)/Al molar ratio in soil solution is a useful indicator to evaluate and predict the effects of soil acidification due to acid deposition on whole-plant dry matter production of Japanese forest tree species at the present time and in the future, and (3) Japanese coniferous tree species such as Japanese cedar and red pine are relatively sensitive to a reduction in (Ca+Mg+K)/Al molar ratio in soil solution compared with European forest tree species such as Norway spruce.  相似文献   

19.
Wood ash was applied to a forest ecosystem with the aim to recycle nutrients taken from the forest and to mitigate the negative effects of intensive harvesting. After two years, the application of 8,000 kg ha−1 of wood ash increased soil exchangeable Ca and Mg. Similarly, an increase in Ca and Mg in the Norway spruce fine roots was recorded, leading to significant linear correlations between soil and root Ca and soil and root Mg. In contrast to these macronutrients, the micronutrients Fe and Zn and the toxic element Al decreased in the soil exchangeable fraction with the addition of wood ash, but not in the fine roots. Only Mn decreased in soil and in fine roots leading to a significant linear correlation between soil and root Mn. In soil, as well as in fine roots, strong positive correlations were found between the elements Ca and Mg and between Fe and Al. This indicates that the uptake of Mg resembles that of Ca and that of Al that of Fe. With the wood ash application, the pH increased from 3.2 to 4.8, the base saturation from 30% to 86%, the molar basic cations/Al ratio (BC/Al) of the soil solution from 1.5 to 5.5, and the molar Ca/Al ratio of the fine roots from 1.3 to 3.7. Overall, all below-ground indicators of soil acidification responded positively to the wood ash application within two years. Nitrate concentrations increased only slightly in the soil solution at a soil depth of 75–80 cm, and no signs of increased heavy metal concentrations in the soils or in the fine roots were apparent. This suggests that the recycling of wood ash could be an integral part of sustainable forest management because it closes the nutrient cycle and reverses soil acidification.  相似文献   

20.
Calba  Henri  Firdaus  Cazevieille  Patrick  Thée  Charles  Poss  Roland  Jaillard  Beno^it 《Plant and Soil》2004,260(1-2):33-46
The goals of this work were to understand the dynamics of H+, Al and Ca in the rhizosphere of maize cultivated in tropical acid soils, and to evaluate the contribution of the dissolution kinetics of the Al-hydroxides to Al dynamics. The study of the dissolution kinetics was based on a comparison between experimental and simulated data, using a model of the chemical processes in the rhizosphere. Two Oxisols, pH 5.1 and 4.6, and one Ultisol, pH 5.2, were studied. An Al-tolerant maize variety (Zea mays L.) was grown for 14 days on a 3-mm thick soil layer. The composition of the soil and the soil solution, together with the concentration of Al in the roots, were determined throughout the experiment. The results showed that root growth (i) decreased the soil solution pH, up to one pH unit, (ii) increased Al concentration in the soil solution, (iii) increased exchangeable Al, and (iv) decreased exchangeable Ca. Soil solution pH, exchangeable Al, and exchangeable Ca were closely linked. Exchangeable Al increased 1.5 – 3.0 times, due to the dissolution of easily mobilised Al components. In addition, Al accumulation in roots depended mainly on Al in the soil solution. Modelling the interactions between H+, Al, and Ca proved that the main factor determining Al in the soil solution was the kinetic reactivity of the easily mobilised Al components. These components, probably poorly crystallised Al-hydroxides, are key players in the functioning of the rhizosphere in tropical acid soils.  相似文献   

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