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1.
An inference technique is developed that allows estimation of the annual and monthly dry deposition of Ca2+, Mg2+, Na+, and K+. Conceptually, this technique is based on the premise that precipitation efficiently scavenges aerosols, resulting in a strong correlation between concentrations within precipitation and the surface-level air. Empirically, it is based on the linear relationship exhibited between the measured surface-level air and precipitation concentrations at 23 stations in Ontario, Canada, for the period 1983–1985. Correlations ranged from 0.513 for K+ to 0.946 for Mg2+. Because of the stochastic nature of such an approach, the assumptions inherent to the concept of scavenging ratios, and therefore this inference technique, must be carefully considered. Under such considerations, annual and monthly dry deposition of alkaline aerosols can be estimated at many locations across North America where precipitation concentrations are routinely measured.  相似文献   

2.
The climatic conditions of the humid tropical areas of México allow the year-round production of cut flowers and potted plants of anthurium. However, the scarce basic and applied research on tropical ornamental species limits the development of technology to increase productivity and quality. In this article, we are reporting the information as to the effect of the proportions of potassium (K+), calcium (Ca+2), magnesium (Mg+2) in the nutrient solution on anthurium growth using mixture analysis and response surface methodology. The sum of all the three cations was 20 meq L?1 and each one is expressed as a fraction of this total concentration. Response surface analysis detected that spathe and leaf areas decreased in plants fed with solutions of high proportions of Mg+2. Total shoot and root fresh weight, as well as total dry weight and root volume, also demonstrated the deleterious effects of high Mg+2. In general, the best growth occurred in two areas of the explored space; a) an area of high Ca+2, with optimum proportions ranging from 0.24–0.44 for K+, 0.54–0.68 for Ca+2, and 0.01–0.08 for Mg+2, and b) another area of high K+, on which the optimum proportions ranged 0.54–0.65 for K+, 0.25–0.29 for Ca+2, and 0.10–0.21 for Mg+2. Shoot and root K+, Ca+2, and Mg+2 concentration was significantly affected by the cation balances in the external solution, however, there was not a clear tendency as to the effect of each cation in the mixture; nonetheless, the internal K+: Ca+2: Mg+2 balances were affected by the balances in the nutrient solution, as in the shoot they were located in a very specific area of the explored space, indicating that anthurium plants accumulated more Mg+2 compared to what it is in the external solution, whereas Ca+2 was lower than that of the external solution. Plants accumulated K+ at high rates regardless of the external balance. In conclusion, the optimum nutrient solutions for anthurium may contain very wide ratios of K+ as long Ca+2 and Mg+2 are maintained at low proportion in the nutrient solution.  相似文献   

3.
西藏土壤钙、镁、钾、钠的迁移和聚集特征   总被引:1,自引:0,他引:1  
采用统计分析方法,研究了西藏土壤钙、镁、钾、钠的含量变化和迁移聚积特征。结果表明,碳酸盐土的盐基氧化物总量高于硅铝土,且以CaO占优势,后者则以K2O占优势。土壤各类盐基元素含量的剖面层间变异系数(CVP)的大小趋势为CaO最大,MgO次之,Na2O与K2O均较小,显示钙是盐基迁移聚积中最活跃的元素。据土壤剖面的盐基聚积指数(BAIP),西藏主要土壤盐基的迁移聚积可分为盐基表聚型(BAIP1.0)和底聚型(BAIP1.0)两种基本模式。土壤盐基迁移聚积主要由钙(有时伴有镁)的迁移聚积引起,一般与钾、钠无关,故概括为积钙作用。积钙作用按其成因分为:①表聚型生物积钙;②化学积钙,又可分为底聚型和亚表聚型;③表聚型化学-生物积钙。  相似文献   

4.
利用电镜技术研究了不同pH(4.0和6.0)和氮形态(NH4+-N和NO3---N)对小麦根系超微结构及根中Ca2+分布的影响。结果表明,1)pH.4.0处理下细胞结构中Ca2+明显少于pH.6.0处理;2)低pH造成质壁分离;3)铵态氮源处理下细胞结构中Ca2+明显少于硝态氮源处理,尤其体现在细胞间质、细胞壁、细胞膜上;4)铵态氮源处理也会导致细胞出现质壁分离,细胞结构松散,胞质外流;低pH加重这些现象。  相似文献   

5.
Na+,K+-ATPase调节肝再生增强因子促HepG2细胞增殖   总被引:1,自引:0,他引:1  
采用四甲基噻唑盐(M TT)法检验肝再生增强因子(ALR)对H epG 2细胞增殖作用;[3H]-T dR掺入测定细胞DNA合成;采用无机磷比色法测定细胞N a ,K -ATPase的酶活力。结果表明:ALR通过促进H epG 2细胞DNA合成,使细胞增殖,并存在剂量效应正相关性(P<0.01);ALR对N a ,K -ATPase酶活呈剂量时间依赖型影响;奎巴因可以通过抑制细胞N a ,K -ATPase影响ALR对H epG 2细胞增殖促进作用。因此,N a ,K -ATPase能参与调节ALR促进H epG 2细胞的增殖。  相似文献   

6.
Abstract

Plant physiologists resort to plant tissue digestion to evaluate the nutrient status of crops, and to study ionic kinetic absorption and antagonism. This paper describes the effectiveness of six extraction procedures (2 non‐digestion, 3 wet‐digestion and the conventional dry‐ashing technique), in evaluating the content of 4 major cations (Ca2+, K+, Mg2+ and Na+) in sour orange leaves (Citrus aurantium L.). Analytical results, experimental advantages and limitations have been compared and discussed among all six procedures. The statistical studies carried out recommend the wet‐digestion as the optimum procedure to evaluate the mineral status of citrus leaves, and as a method with numerous technical advantages.  相似文献   

7.
芙蓉洞洞穴水Ca2+,Mg2+浓度变化对气候事件的响应   总被引:2,自引:0,他引:2  
对重庆市芙蓉洞内的两处滴水(1#,3#)和两处池水(2#,4#)进行了定点观测和取样分析.获得了4处洞穴水的pH、电导率和Ca2+.Mg2+.K+,Na+.SO2-4,Cl-离子浓度等化学指标.结合当地的气象资料,分析研究了观测期间芙蓉洞洞穴水Ca2+,Mg2+浓度在不同季节的变化规律及其对温度和降水的响应,重点对这两种离子与2006年和2007年夏季重庆特大干旱和降水极端气候事件的响应关系进行了探讨.结果显示:Ca2+浓度呈现以年为周期每年7-12月高于1-6月的变化规律,一年中Mg2+表现出波动期与稳定期交替出现的特点,Ca2+,Mg2+浓度在2006年9月明显升高,表明其对2006年夏季特大干旱事件的响应敏感.短期干旱导致洞穴水离子浓度偏高;2007年夏季的暴雨事件后Ca2+,Md2+浓度波动较大,表明洞穴水对特大降水事件响应明显,但各个点的响应时间存在差异.  相似文献   

8.
This study assessed the relationships between external K+ supply and K+ : Na+ ratios associated with Na+ toxicity in Jatropha curcas. Plants were exposed to increasing external K+ concentrations (6.25, 12.5, 25, 37.5, and 50 mM), combined with 50 mM NaCl in a nutrient solution. Photosynthesis progressively increased as the external K+ : Na+ ratios increased up to 0.75. The increase of photosynthesis and plant dry matter correlated positively with K+ : Na+ in xylem and leaves. The transport rates of K+ and Na+ from roots to xylem and leaves were inversely correlated. These ions presented an antagonistic pattern of accumulation in all organs. Maximum rates of photosynthesis and plant growth occurred with leaf K+ : Na+ ratios that ranged from 1.0 to 2.0, indicating that this parameter in leaves might be a good indicator for a favorable K+ homeostasis under salinity conditions. The higher K+ affinity and selectivity compared with Na+ in all organs associated with higher xylem flux and transport to shoots are essential for maintaining adequate K+ : Na+ ratios at the whole‐plant level. These characteristics, combined with adequate K+ concentrations, allow J. curcas to sustain high rates of photosynthesis and growth even under toxic NaCl levels.  相似文献   

9.
洞穴水Ca^2+,Mg^2+含量及其变化量是洞穴次生化学沉积物发育程度的最直接和最基础的反演载体。通过对芙蓉洞地表水、基岩水及洞穴水进行采样对比分析认为:(1)芙蓉洞洞穴水Ca^2+,Mg^2+含量总体变化不大,Ca^2+离子含量为44~52mg/L.Mg^2+离子含量为32~45mg/L。洞穴次生化学沉积物的主要物质来源是Ca^2+离子.正处于Ca^2+离子沉淀较为完全,而Mg^2+离子还没来得及甚至没有开始沉淀阶段。(2)碳酸盐岩地区次生化学沉积物Ca^2+/Mg^2+比值在一定程度上反映了其景观发育成熟度。不同岩溶地区的岩石渗透性在很大程度上影响岩溶洞穴次生化学沉积物的发育程度及速率。(3)洞穴水Ca^2+,Mg^2+离子含量与洞穴次生化学沉积物发育特征关系不大。(4)10年来,芙蓉洞洞穴水Ca^2+离子含量变化,在很大程度上影响次生化学沉积物发育度。和Mg^2+离子关系不大。外界能量输入引起的温度升高对次生化学沉积物发育程度影响较小,而pH值的改变对它影响较明显。  相似文献   

10.
采用室内模拟降雨装置,对供试的密云县农田褐土分别进行了在3种不同地表状况(裸地、草皮覆被、秸秆覆盖),3种降雨强度(60 mm/h,90 mm/h,120 mm/h),5种坡度(10°,15°,20°,25°,30°)下的交叉实验,对不同降雨时间段下表层径流水中K、Na、Ca、Mg流失量进行测试分析,结果表明在坡度10°,15°的3种降雨强度下,各阳离子流失量在相同时间段内总体表现为秸秆覆盖<草皮覆被<裸地,在坡度20°,25°,30°时草皮覆被对各阳离子流失量的抑制效果明显;相同地表、坡度和降雨时间段,K、Na、Ca、Mg流失量均表现出60 mm/h<90 mm/h<120 mm/h,Mg规律性最强;相同雨强和降雨时段下,草皮覆被和秸秆覆盖地表下Na、Ca、Mg流失量随着坡度的增加呈递增态势;随着时间段的增加各阳离子流失量总体呈递增态势,只有在雨强90 mm/h时部分元素有所差异;相同雨强1h时段内不同阳离子流失总量之间随坡度的变化存在相关性.  相似文献   

11.
Abstract

The seasonal patterns of foliage nutrient concentrations and contents were monitored for two growing seasons in an 11‐year—old Pinus el1iottii stand. In the first growing season after needle initiation, N, P, K, Mg, and Zn concentrations decreased, but this was followed by an increase in the fall and winter months. Another drop in concentration of all elements, except P, occurred in the second growing season. Decreases in total contents indicated that this drop was a result of translocation to other tissues. In contrast to the mobile elements, the concentration and fascicle contents of Ca, Mn, and Al increased with aging of the needles.

Between‐tree variability was least for N, P, and Zn and the N, K, Mg, Mn, and Zn in the current foliage had consistently lower variation than that in the 1‐year‐old foliage. Between‐tree variation for K was lower in the winter than the spring.

For pine foliage, recommended sampling period for N, P, Mg, and Zn is mid to late summer and for the other elements it is late fall to late winter.

There are several sources of variation that influence the level of nutrients in tree foliage. The most important of these, apart from the tree nutrient status, are seasonal fluctuations, variation between trees, and age of needles . Smaller sources of variation are associated with position of the needles within the crown, diurnal changes, year to year variation, and analytical errors1,2. These variables must be studied in order to develop suitable sampling techniques and in Pinus this has been undertaken for P. banksiana 1, P. taeda 3, P. strobus 4, P. resinosa 4, P. sylvestris 5, and P. radiata 6,7. However, foliage sampling has not been studied in detail for slash pine (Pinus elliottii Englem var. elliottii) and earlier studies with other pines have been largely confined to temperate or cool climates.

This study reports the variation in elemental concentrations with season, age of foliage, and between slash pine trees growing in a subtropical climate in Florida.  相似文献   

12.
The acidic soils of temperate forests and some pastures on former forest land characteristically contain large amounts of aluminium and hydrogen ions and small amounts of calcium and magnesium ions. The relative importance of these potential toxicity factors are assessed from published data from soils collected in the United States and Europe. Activities of ions in the soil solutions and at the surfaces of root‐cell plasma membranes were computed with electrostatic models. Activities of Al3+ in soil solutions ({Al3+}) peaked at pH 4.1, and Al3+ activities at the surface of the plasma membrane ({Al3+}0) achieved a broad maximum between pH 4.1 and 4.8; thus, Al3+ intoxication is likely to be more severe in soils at pH 4.1 than in more acidic ones. Intoxication (assessed by root elongation) correlated somewhat ambiguously with ion activities, but Al3+‐ and H+‐induced depletion of Ca2+ and Mg2+, or both, from the cell surface appears to play a role in toxicity. By contrast, experiments in solution culture, where intercorrelation among {Al3+}, {H+}, and {Ca2+} could be avoided, clearly demonstrated the following extrinsic and intrinsic effects. 1 The ions Al3+ and H+ are intrinsic toxicants. 2 They are also extrinsic toxicants because of the electrostatic displacement of Ca2+ from the surface of the plasma membrane. 3 They are extrinsic ameliorants because each electrostatically displaces the other from the surface of the plasma membrane. 4 The ion Ca2+ is an extrinsic ameliorant because of the electrostatic displacement of Al3+ and H+ from the surface of the plasma membrane. 5 It is an intrinsic ameliorant of intrinsic H+ toxicity, but not intrinsic Al3+ toxicity. 6 It meets an intrinsic requirement. 7 The ion Mg2+ resembles Ca2+ in item 4 but not items 5 and 6 in short‐term cultures. In acidic soils, Al3+ may prevent H+ from becoming an intrinsic toxicant (item 3) and may induce an insufficiency of Ca2+ and Mg2+ (item 2). These findings have implications for the mechanisms by which woodland plants tolerate very acidic soils.  相似文献   

13.
通过水培试验探讨了NO3-胁迫下K 、C a2 对黄瓜幼苗膜质过氧化及活性氧清除酶系统的影响。结果表明,在相同NO3-浓度胁迫7d后,C a2 浓度越大,膜脂过氧化产物丙二醛(M DA)含量越高,而K 浓度越大,电解质相对渗透率越高,由此说明K 、C a2 对细胞膜造成伤害的机理不同。黄瓜幼苗活性氧清除酶系统对K 、C a2 的响应亦不同,在一定程度上,K 和C a2 可提高SOD、POD和CAT活性,保护植物免受自由基伤害,继而可增强植物对逆境的适应能力。  相似文献   

14.
近年来以微囊藻为优势种的太湖蓝藻水华持续暴发,已经成为严重的环境问题之一。本文通过现场采样及室内分析,研究了2009年太湖南泉水域蓝藻发生过程中藻类群落组成的变化,并同步研究了蓝藻体内及其水环境中常量元素Ca、Na、Mg、K和Al元素浓度的周年变化,分析了三者之间可能的相关性。研究显示,太湖蓝藻发生时间为6—10月,期间水温保持在20℃以上,pH值在水华发生后期可升高至9.8;水体中元素浓度依次为Na〉Ca〉Mg〉K〉Al,而水华蓝藻中元素浓度依次为Ca〉K〉Mg〉Na〉Al;藻体对水体环境中元素的富集系数大小依次为Al〉K〉Mg〉Ca〉Na。研究结果既为选择最佳物理除藻时期来有效降低湖泊中常量元素的负荷量,从而进行水华控制提供了支撑,也为今后将富含元素的水华蓝藻作为"生物矿源"加以利用提供了理论依据。  相似文献   

15.
Mineral regulation of two soybean varieties Jackson and Lee was investigated in long term water culture experiments using saline solutions. The effects of extreme K:Na ratios using chloride and sulfate as counterions were studied in the early stages of salinity.

The growth rates of both varieties were not affected by salinization. A K+ stimulated, intensive acropetal Cl translocation was observed in the salt sensitive variety Jackson. The varieties did not differ in Na+ translocation and in the suppression of Ca2+ and Mg2+ in the leaves. But the effect of the nature of salinization indicates already differences in Na uptake and translocation of the cultivars.

The avoidance of Cl, but also of Ha+, in connection with influences of the resulting ionic imbalance on metabolic pathways are probably the most causative factors for the different tolerance to salinity of the two soybean varieties.  相似文献   

16.
为了揭示多种金属离子共存的含盐废水生物处理系统污染物的去除机制和污泥特性,考察Na~+、K~+共存对A~2/O工艺污染物去除率、污泥性质和微生物群落的影响,采用高通量测序技术分析了厌氧区、缺氧区和好氧区的微生物群落结构,结合脱氮除磷效果和污泥性质的变化,探讨不同Na~+/K~+摩尔比下A~2/O工艺优势种群的演替规律,以期从微生物角度明确Na~+、K~+共存对含盐废水污染物去除率的影响。结果表明:当进水Na~+/K~+摩尔比分别为2、1和0.5时,A~2/O工艺的COD去除率分别为80%、84%和86%,TN去除率分别为73%、77%和80%,K~+浓度的提高缓解了Na~+对COD和TN去除率的抑制作用;厌氧区释磷率分别为70%、73%和74%,缺氧区吸磷率分别为53%、55%和58%,好氧区吸磷率分别为70%、72%和75%。随着进水Na~+/K~+摩尔比的降低,厌氧区、缺氧区和好氧区微生物群落的丰富度和多样性降低,微生物群落差异显著,变形菌门的相对丰度均升高约30%,拟杆菌门和绿弯菌门相对丰度逐渐降低。陶氏菌属和固氮弧菌属作为优势菌属,其相对丰度逐渐增大,有利于氮磷污染物的去除。通过增加K~+的浓度有利于提高氮、磷去除率,增强污泥的生物絮凝性和反硝化聚磷菌的活性。  相似文献   

17.
The relation between activity of soluble acid invertase and sucrose content in leaves of young bushbeans (salt sensitive) and sugarbeets (salt tolerant) and ion‐specific effects of salinity environment were investigated. For comparison the response of isolated invertase from both plant species to ion combination and ion concentration was investigated. The plants were grown in water culture under controlled conditions.

In busbean leaves invertase activity decreased while sucrose increased. K+ with Cl as counterion was most effective “in vivo”;. However, there was little change in invertase activity or sucrose content in sugarbeet leaves. Independent of the origin of the enzyme, invertase activity was not affected by either ion concentration or ion combination “in vitro”;. Acid invertase might be a key enzyme in the utilization of carbohydrates. The ionic effect on acid invertase activity and carbohydrate content in intact plant tissue could be a possible indicator of salt tolerance of crops.  相似文献   


18.
Abstract

Nitrapyrin in the presence of a plant decreased N2O evolution after a five to six day period of incubation. These findings show that the inhibiting effect of nitrapyrin on the denitrification process is indirect. Evidence is also presented that suggest N2O evolution is greater in the presence of a plant and thus cropped soils, than from bare soils.  相似文献   

19.
生物炭与沸石混施对不同污染土壤镉形态转化的影响   总被引:10,自引:2,他引:10  
采用室内培养模拟了低(1.0 mg/kg)、高(10 mg/kg)镉污染的土壤,通过向镉污染土壤中添加0.4%,2%,10%的1∶1的生物炭和沸石的混合物,探究了生物炭及沸石混施对不同程度镉污染土壤的pH和镉形态变化的影响。结果表明:2种不同程度镉污染土壤的pH均较CK有所提高,且随钝化剂用量的增加而增大。随着培养时间的延长,低污染土壤pH呈现降低趋势,而高污染土壤pH先升高后降低最后趋于稳定。培养后期,低污染和高污染土壤在混合物添加量分别为2%和10%时有效态镉降低比例最大,降低比例分别为56.78%和27.33%。各处理土壤随生物炭和沸石混合物添加量的增加交换态镉降低比例逐渐增大,培养后期,低污染土壤的交换态镉较CK分别降低8.35%,13.81%,20.65%,高污染土壤的交换态镉较CK分别降低10.02%,22.34%,33.01%。各处理的钝化剂能够明显的降低交换态镉的含量,增加碳酸盐结合态、铁锰氧化物结合态、有机结合态和残渣态镉的含量,低污染土壤的有机结合态明显高于高污染土壤。由此可见,生物炭与沸石混施能够降低土壤重金属的生物有效性,为农田土壤修复奠定了理论基础。  相似文献   

20.
Abstract

The concentrations of K+, Na+, and proline and the ratio of K+ to Na+ (K+ / Na+) were analyzed in NaCl-unadapted and NaCl-adapted tobacco (Nicotiana tabacum) cells in suspension culture. At 3 to 5 d after inoculation, the NaCl-unadapted cells cultured in 100 mmol L?1 NaCl saline culture medium (Na100 medium) accumulated 28.7 mmol L?1 proline with a low ratio of K+ to Na+ (= 2.8) and the NaCl-adapted cells cultured in the Na100 medium contained 6.28 mmol L?1 proline with a high K+ / Na+ ratio (≧ 7.5). The contents of amino acids for the NaCl-adapted cells in the Na100 medium were similar to those for the NaCl-unadapted cells in a modified LS medium (standard medium). At 14 d after inoculation, the NaCl-unadapted cells in the Na100 medium contained 4.77 mmol L?1 proline and restored the K+ / Na+ ratio from 2.8 to 6.2. These results indicate the presence of a negative correlation between the K+ / Na+ ratio and proline accumulation and suggest that a balance between the K+ / Na+ ratio and proline accumulation may be the factor involved in determining the salt tolerance of plant cells.  相似文献   

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