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1.
Effects of Ca^2＋concentrations on accumulations of mineral elements in the components of Pteroceltis tatarinowii 总被引：2，自引：0，他引：2
The bark ofPteroceltis tatarinowii is a raw material for manufacturing Xuan Paper. The effects of Ca2+ concentrations on the accumulation of mineral elements in the bark, leaf and root ofPteroceltis tatarinowii were studied under controlled conditions. The types of Hoagland nutrient solution with three Ca2+ concentrations levels (200, 400 and 600 μg·g−1) and a control (without Ca2+ were designed to culturePteroceltis tatarinowii. After 6 months, contents of seven mineral elements including Ca, K, Mg, Mn, Zn, Cu and Na in the root, leaf and bark were
analyzed. The results indicated that Ca accumulations content in the root, leaf and bark had positively relation with Ca2+ concentrations (200, 400, 600 μg·g−1), and the order of the Ca content in the three components was root>leaf>bark. Ca content in the root treated with 600 μg·g−1 Ca2+ concentrations was 5.5 times as high as that of the control, and about 1.4 times as high as that of the root treated in 200
and 400 μg/g Ca2+ concentrations respectively. On the contrary, K and Mg contents in the root, leaf and bark were negatively related to Ca2+ concentrations, especially in the bark, and their accumulation trend followed the order of leaf>root>bark. K content in the
bark treated with 600 μg·g−1 Ca2+ concentrations was 39.3% of that of the control, and was 79.0% and 91.8% of that of the bark treated with 200μg·g−1 and 400μg·g−1 Ca2+ concentrations respectively; Mg content in the bark treated with 600μg·g−1 Ca2+ concentrations was 23.4% of that of the control, and was 27.1% and 35.4% of that of the bark treated with 200 and 400 μg·g−1 Ca2+ concentrations respectively. Compared with the control, the general tendency of Mn, Zn and Cu content decreased with increasing
of Ca2+ concentrations and their contents were in the order: root>leaf>bark. Based on the results of this study, the experiment has
been useful for providing academic bases in improving the bark quality ofPteroceltis tatarinowii on non-limestone soil.
Foundation item: This paper is supported by National Natural Science Foundation of China (No. 39970608).
Biography: Fang Shengzun (1963), male, Professor in Stiiviculture, Nanjing Forestry University, Nanjing 210027, P.R. China.
Responsible editor: Zhu Hong 相似文献
2.
The changes of Ca2＋ levels in young leaf cells of bromegrass under different controlled chilling temperatures were inves- tigated by an antimonite precipitation cytochemical method. The main results were as follows： under 25/20℃ （day/night） tempera- ture and 14 h photoperiod, electron-dense Ca2＋ antimonite precipitates, indicators of Ca2＋ localization, were mainly localized in the vacuoles, cell walls and intercellular spaces; few Ca2＋ deposits were observed in the cytosol and nuclei. After a 3℃ chilling treatment for 3 h, many Ca2＋ precipitates appeared in the cytosol and nuclei, indicating that Ca2＋ influx had occurred in the cytosol and nuclei. When the 3℃ treatment was prolonged to 8 h, more Ca2＋ deposits appeared in the nuclei and cytosol, but the amount of Ca2＋ deposits in both the cytosol and nuclei decreased markedly after a 24 h treatment and most Ca2＋ deposits were returned to the vacuoles and intercellular spaces after an 8 d treatment. When bromegrass was exposed to 7℃ for 3 h, the Ca2＋ distribution in the cells had no visible changes, compared with that of the 25/20℃ grown control plants. However, when the chilling treatment of 7℃ was prolonged to 8 h, a Ca2＋ influx occurred, where many Ca2＋ deposits were observed in the nuclei and cytosol. More Ca2＋ deposits appeared in the nuclei and cytosol after a 24 h treatment, but the amount of Ca2＋ deposits in the cytosol and nuclei was reduced markedly after an 8 d treatment. After a 14 d treatment, the remaining low level of Ca2＋ was recovered in both the cytosol and nuclei and the Ca2＋ deposits were again located in the vacuoles and the intercellular spaces. The dynamics of subcellular Ca2＋ localization in young leaf cells of bromegrass during a 12℃ chilling treatment were similar to those of the 7℃ treatment. Besides, the results showed that the frost tolerance ofbromegrass exposed to 3℃ for 8 d increased by 6℃, for 7℃ and 8 d by 4℃ and for 12℃ and 14 d by 3℃, compared with the controls. 相似文献
3.
Potassium antimonite was used to localize Ca^2 in the apical bud cells of spruce from July 1999 to May 2000.During the period of active growth (July 14), Calcium precipitates, an indication of Ca^2 localization, were mainly distributed in vacuoles, intercellular spaces and cell walls. Few Ca^2 deposits localized in the cytosol and nucleus, showing a low level of the cytosolic and nuclear Ca^2 concentration in the warm summer. In August, some Ca^2 deposits appeared in the cytosol and nuclei,indicating that Ca^2 influx occurred in the cytosol and nucleus as the day length became shorter. From September to November, high levels of the cytosolic and nuclear Ca^2 remained. During the mid-winter (December and January), the distribution of Ca^2 deposits and the ultrastructures in the cells were altered dramatically. Plasmolysis occurred in many cells due to the protoplasmic dehydration.In addition plasmalemma invagination and nuclear chromatin aggregation also occurred. A large number of Ca^2 deposits appeared in the space between the plasmalemma and the cell wall. And also some Ca^2 deposits were distributed in the plastids. However, few Ca^2 deposits were observed in the cytosol and nuclei. By spring of the next year (May), when plants were de-acclimated and resumed active growth, Ca^2 subcellular localization essentially restored to that observed in July of the last year, i.e., the cells contained low cytosolic and nuclear Ca^2 concentrations; Ca^2 deposits were mainly distributed in the vacuoles, cell walls and intercellular spaces. The relationships between the seasonal changes of intracellular Ca^2 concentration and the development of dormancy/cold acclimation, as well as plasmolysis associated with dormancy and cold hardiness were discussed. 相似文献
4.
The effects of anethol, the major component of anise oil, on the Ca2+-dependent excitability and afterhyperpolarization (AHP) in snail neurons were examined using intracellular recording. Anethol (0.5%) significantly broadened the spike, reduced the firing frequency and enhanced the AHP amplitude. In contrast, anethol (2%) significantly increased the firing frequency and decreased the AHP. Blockade of Ca2+ channels after anethol application depolarized the membrane potential and significantly reduced the firing rate. Furthermore, in the presence of anethol (0.5%) a significant decrease in the AHP was observed by Ca2+ channels blockage. Here, anethol-induced functional modification of Ca2+ and Ca2+-activated K+ channels is suggested. 相似文献
5.
Scoparone is an important constituent of Yinchenhao (Artemisia annua L.), a famous Chinese medicinal plant, and has several known bioactivities, and displayed bright prospects in prevention and therapy of jaundice and liver disorders. The aim of this study was to investigate the in vivo plasma pharmacokinetic and tissue distribution characteristics of scoparone after oral administration. The levels of scoparone in plasma, and tissues were measured by a rapid and sensitive UPLC-MS/MS method. The biosamples were prepared using methanolic precipitation and the separation of scoparone was achieved on a UPLC HSS T3 column by linear gradient elution using water (containing 0.1% formicacid) and acetonitrile (containing 0.1% formic acid) as the mobile phase at a flow rate of 0.5mL/min The total run time was only 3.9min. Our results successfully demonstrate that this method has excellent and satisfactory selectivity, sensitivity, linearity, precision, accuracy and recovery. The estimated pharmacokinetic parameters (i.e., C(max), AUC and CL), were C(max)=14.67mg/L, AUC=81.15mg*h/L, CL=1.23L/h for scoparone. The pharmacokinetic study found that scoparone was distributed and eliminated rapidly in rats. Tissue distribution showed the highest level was observed in liver, followed by the kidney and spleen; the lower level appeared in the muscle, thyroid, and adrenal. It was not detected in the brain which indicated that scoparone does not cross the blood-brain barrier after oral administration. Our developed method was suitable for the study on pharmacokinetics and tissue distribution of scoparone after oral administration. 相似文献
6.
The purpose of this study was to investigate the modulating effects of phyllanthin and hypophyllanthin on vascular tension, using in the in vitro model of isolated rat aorta. Our results indicated that both phyllanthin and hypophyllanthin significantly relaxed the sustained contraction induced by phenylephrine (PE) in a concentration-dependent manner. In addition, endothelial removal had no significant influence on the vasorelaxation responses of the aortic rings toward these two compounds. Furthermore, both compounds inhibited the contraction of aortic muscle provoked by either PE (1 μM) or KCl (40 mM) as well as the spontaneous contraction of the Ca2+-depleted muscle. In high K+- Ca2+ free solution, phyllanthin (100 μM), but not hypophyllanthin, significantly inhibited the contractile responses upon cumulative addition of CaCl2. Both compounds (100 μM) significantly inhibited PE-induced contraction in Ca2+-free condition, but could not affect caffeine-induced contraction. Taken together, phyllanthin and hypophyllanthin could modulate the vascular tension via the endothelium-independent mechanisms. The modulating effects of both compounds were possibly involved with the blockade of Ca2+ entry into vascular smooth muscle cells and inhibition of PE-mediated Ca2+ release from sarcoplasmic reticulum. 相似文献
7.
We studied ion distribution in roots and the growth of Cyclocarya paliurus seedlings of three provenances, Huangshan in Anhui, Jiujiang in Jiangxi and Kunming in Yunnan, under conditions of 0, 1,
3 and 5 g/L NaCl stress using X-ray microanalysis. Results show that under NaCl stress of 3 and 5 g/L, the relative contents
of Na+ and Cl− in root tissues increased, while the relative contents of K+, Ca2+ and Mg2+ decreased. With an increase in salinity, the relative content of Na+ in the epidermis and cortex of the root increased, while the relative content of Cl− in the stele and cortex of the root increased markedly. Thus, ions in the root tissues were unbalanced and the ratios K+/Na+ and Ca2+/Na+ decreased, while Na+/(K++ Na++Ca2++Mg2+) increased. The decrease of the K+/Na+ ratio and the substantial increase of Cl− in root tissues contributed to a decline in seedlings survival and reduced the increments for seedling leaf area, height,
basal diameter as well biomass. Our preliminary conclusion is that the level of salt tolerance for the tested provenance seedlings
was in the order of Huangshan > Kunming > Jiujiang, and the threshold of salt tolerance for C. paliurus seedlings was about 1 g/L.
__________
Translated from Scientia Silvae Sinica, 2008, 44(6): 66–72 [틫自: 쇖튵뿆톧] 相似文献
8.
The inhibitory effect of piperine from Fructus piperis extract on the degranulation of RBL-2H3 cells
《Fitoterapia》2014
Allergy is an abnormal immune response to an allergen. Type I hypersensitivity is an immunoglobulin (Ig) E-mediated allergic disorder. Fructus piperis is derived from the ripe fruit of the pepper, which is widely used as a spice in human diets and is also administered as a medicine in many countries. Piperine has been shown to have anti-oxidant, anti-depressant, anti-tumor, and anti-inflammatory activities. However, the effect of piperine on IgE-mediated allergic responses has not been reported. Here, the rat basophilic leukemia cells by membrane chromatography (RBL-2H3/CMC) coupled to high performance liquid chromatography/mass spectrometry (HPLC/MS) to discover and identify piperine can bind to RBL-2H3 cell membranes. Piperine inhibited the expression of cytokines, and the release of both β-hexosaminidase and histamine, which could be stimulated by antigen in RBL-2H3 mast cells. We found that the levels of intracellular Ca2 + also decreased. Furthermore, RT-PCR showed that the mRNA expression levels of IL-4, IL-13, and TNF-α were significantly suppressed by piperine. The inhibitory effect of piperine on IgE-mediated degranulation and cytokine production by RBL-2H3 cells may be caused by the inhibition of IgE-mediated signaling pathways, including the phosphorylation of Lyn, p38, Erk, and Ras. In summary, piperine can inhibit antigen-induced allergic reactions that control degranulation. 相似文献
9.
Renjun Xiang Liyuan Chai Xilin Zhang Gong Zhang Guifang Zhao 《Frontiers of Forestry in China》2008,3(3):321-325
Leaching of major ions from acid precipitation in a subtropical forest was examined based on an experiment in four sample
sites in Shaoshan City, Hunan Province, China, from January 2001 to June 2002. Results clearly show that when rain passed
through the canopy, pH increased and the evidence of ion uptake was presented for SO4
2−, NO3
−, Mg2+ and NH4
+ ions, especially of NH4
+ and NO3
−. The percentages of dissolved SO4
2−, Ca2+ and Mg2+ show a decreasing trend with increasing rainfall. Percentages of leaching Ca2+, K+ and Cl− ions show an increasing trend as a function of increased pH values. The forest canopy in Shaoshan City has a strong effect
on the uptake of SO4
2− and NO3
− ions under acid rain conditions. The decreasing order of ions leaching in the forest canopy is as follows: K+ > Ca2+ > Cl− > Mg2+ > SO4
2− > NO3
− > NH4
+ > Na+.
__________
Translated from Scientia Silvae Sinicae, 2007, 43(7): 1–4 [译自: 林业科学] 相似文献
10.
Our previous studies have shown that cyclovirobuxine D (CVB-D) ameliorated the cardiac function in heart failure rats. Considering the relationship between cardiac function and [Ca2 +]i, and the role of calcium cycling on regulating [Ca2 +]i, the present study was designed to evaluate the influence of CVB-D on the calcium transient of myocytes from neonatal rats and adult heart failure (HF) rats. The expression of calcium cycling proteins, including L-type calcium channel (LTCC), ryanodine receptor 2 (RYR2), sarcoplasmic reticulum calcium ATPase 2a (SERCA2a) and sodium–calcium exchanger (NCX), were investigated to explore the underlying mechanism. CVB-D increased the intensity of calcium transient, accelerated the process of calcium transient and attenuation in the neonatal and adult myocytes. Furthermore, CVB-D shortened Tpeak and Tattenuation in the adult myocytes and slowed down the heart rate of neonatal myocytes. Besides, CVB-D increased the expression of RYR2 and SERCA2a, decreased the expression of NCX, but showed no significant effect on LTCC. Thus, it was concluded that CVB-D increased the release and uptake of Ca2 + in systolic and diastolic period, respectively. CVB-D might not only facilitate the utilization of intracellular Ca2 +, but also prevent the loss of Ca2 +. 相似文献
11.
Kraft lignins modified by radical sulfonation or alkaline oxygen treatment were rich in acidic groups, such as sulfonic acid,
carboxylic acid, and phenolic hydroxyl groups, and were effective as soil-conditioning agents, especially because of their
ability to trap aluminum ions eluted from soil under acidic conditions. Formation of complexes between aluminum ions and modified
lignins was examined using potentiometric titration and 27Al nuclear magnetic resonance (NMR) spectroscopy. Changes in the titration curve of a modified lignin by the addition of aluminum
ions suggest the release of protons after the formation of complexes between them. Disappearance of 27Al-NMR signals assigned to various aluminum ions by the addition of kraft lignin treated with alkaline oxygen was also attributed
to the formation of complexes. The relative ease of proton release because of complex formation between a modified lignin
and metal ions was as follows: Fe3+ > Al3+ > Cu2+ > Pb2+ > Mn2+ > Ca2+. This indicates that aluminum complexes are quite stable, and the aluminum ion is not exchanged with cations other than Fe3+.
Received: October 24, 2001 / Accepted: January 16, 2002
Present address: Asian Natural Environmental Science Center, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan Tel. +81-3-5841-7506;
Fax +81-3-5841-5230 e-mail: ukyoko@mail.ecc.u-tokyo.ac.jp
Part of this study was presented at the 11th International Symposium on Wood and Pulping Chemistry, Nice, June 2001
Correspondence to:K.S. Katsumata 相似文献
12.
Long-term influence of stream water chemistry in Japanese cedar plantation after clear-cutting using the forest rotation in central Japan 总被引：1，自引：0，他引：1
Because both natural and anthropogenic disturbances affect biogeochemical cycles in forest ecosystems, monitoring is needed to separate their influences. Chronosequence is very useful for such studies. In our study area, plantation through forest rotation on a watershed basis resulted in more than 40 adjacent watersheds of between 0 and 87 years of stand age, kind of chronosequence. Here, we examined the biological similarity of the watersheds and the long-term effects of clear-cutting on stream water chemistry. The stream water NO3−–stand age relationship was similar between the two observation years; stream water NO3− concentrations increased dramatically in the watersheds after clear-cutting and decreased in 7–10-year-old replanted watersheds. The slope of stream water NO3− concentrations between the different watersheds covered by same age stand was significant, at 1:1. Additionally, stream water NO3− concentrations were more strongly correlated between the different watersheds covered by same aged stand than between the observations at 4 years intervals within a watershed. These findings indicate that stream water NO3− concentration is mainly regulated by stand age, i.e., by vegetation regrowth, rather than watershed-specific characteristics. Hence, adjacent watersheds are biologically similar apart from stand age and can be regarded as a chronosequence. While there was a clear relationship between stream water NO3− concentration and stand age, there was significant correlation with stream water SO42−, Ca2+, Mg2+, Cl− or Na+ between two observations in the same watershed. This indicates that watershed-specific characteristics, rather than vegetation regrowth, control stream SO42−, Ca2+, Mg2+, Cl−, and Na+ concentrations. After 25 years of clear-cutting Ca2+, Mg2+ and Na+ concentrations significantly increased. It is likely the contribution of forest floor accumulation with stand development. Based on these results, clear-cutting influences stream chemistry, not only NO3−, but also the major cation and the influence of clear-cutting continues for several decades at this study site. 相似文献
13.
在六盘山香水河小流域的华北落叶松人工林样地,测定了2011年生长季降水转化过程中的大气降水、穿透水、干流、枯落物渗透水和主根系层(30 cm土层)土壤渗透水的pH值与多种阳离子的浓度及通量变化.结果表明:林外降水的pH值平均为7.13,转化为穿透雨和干流后降为6.73和6.00,转化为枯落物渗透水和土壤渗透水后回升为6.87和7.28.在降水转为由穿透雨和干流组成的林下降水后,绝大多数阳离子的浓度都不同程度地增大,但Zn2+浓度下降;虽然林冠截持使林下降水的数量减小,但由于雨水对林冠的离子交换及淋洗,林下降水的多数阳离子通量都比林外降水明显增大,K+、Mg2+、H+、Mn2+、Cu2+、Fe3+由林外的17.23、12.51、0.06、0.09、0.13、0.19 mmol·m-2分别上升到林下的141.87、32.93、0.10、0.68、0.24、0.56 mmol·m-2,但Na+、Ca2+、Zn2+的通量分别由林外的33.73、112.91、2.05 mmol·m-2减小为林内的30.70、75.75、1.10 mmol·m-2.在枯落物层渗透水中,绝大多数阳离子的浓度都不同程度地下降,仅Mg2+浓度微弱上升;受枯落物截持部分降水及雨水中阳离子与枯落物交换的影响,枯落物渗透水中所有阳离子的通量都比林下降水明显减小,K+、Na+、Mg2+、Ca2+、H+、Mn2+、Cu2+、Zn2+、Fe3+分别降至83.06、12.30、23.96、65.73、0.04、0.12、0.09、0.13、0.32 mmol·m-2.在主根系层土壤渗透水中,一些阳离子(K+、Mn2+、Cu2、Fe3+)的浓度下降,另一些阳离子(Na+、Mg2+、Ca2+、Zn2+)的浓度则上升,尤其Ca2+浓度显著上升;Na+、M2+、Ca2+、Mn2+、Zn2+的通量比枯落物渗透水增大,其值分别为37.49、62.83、202.41、0.22、1.05 mmol·m-2,但K+、Cu2+、Fe3+的通量比枯落物渗透水减小,其值分别为27.14、0.07、0.09 mmol·m-2.相对于林外降水的阳离子输入通量,林冠层对多数阳离子(除Na+、Ca2+、Zn2+)的通量为净淋出(增加)作用,枯落物层对多数阳离子(除K+、Mg2+、Mn2+、Fe3+)的通量为净固定(减少)作用,主根系层土壤对盐基离子(Na+、K+、Mg2+、Ca2+)和Mn2+的通量为净淋失(增大)作用,但对其他阳离子(H+、Cu2+、Zn2+、Fe3+)的通量为净固定(减少)作用. 相似文献
14.
[目的]在不同供Ca2+水平下对马尾松幼苗生长及生理特性进行研究,以确定适宜马尾松生长的钙浓度,为马尾松人工林培育及合理施用钙肥提供参考。[方法]以半年生马尾松幼苗为试材,采用温室内砂培,研究不同供Ca2+水平(0.0、0.4、1.0、2.0、3.0、4.0 mmol·L~(-1)(CK))对马尾松生长及生理指标的影响。[结果]不同供Ca2+水平处理5个月后,在Ca2+水平为1.0、2.0 mmol·L~(-1)时,马尾松幼苗的株高增量和地径增量较高,其中,2.0 mmol·L~(-1)Ca2+水平的株高增量和地径增量最高。马尾松幼苗对Ca2+水平适应能力强弱顺序为2.01.00.43.00.04.0 mmol·L~(-1)(CK)。在不同生长期内,随着供Ca2+水平的增加,马尾松针叶中ROS(O2-产生速率、H2O2浓度)、MDA含量、抗氧化酶(SOD、POD、CAT和APX)活性、抗氧化物质(GSH、As A)含量、脯氨酸含量均先降低后增加,最小值均在1.0 mmol·L~(-1)或2.0 mmol·L~(-1)处理中;类胡萝卜素含量先增加后降低,其最高值均在2.0 mmol·L~(-1)处理中。马尾松幼苗的株高增量和地径增量与类胡萝卜素含量关系不明显,而与其他生理指标均呈显著负相关。[结论]马尾松幼苗适宜在1.0 2.0 mmol·L~(-1)Ca2+水平的环境中生长。在马尾松林地中,应对土壤有效钙含量进行测定,并结合植株的生长和生理特征进行综合评价后,科学合理施肥以提高生产力。 相似文献
15.
We evaluated i) the difference in river water chemistry between a watershed mainly consisting of pasture and a watershed mainly
consisting of forest, and ii) how the chemistry of river draining the pasture is influenced by that of the river draining
the forest. We selected one river (designated as the T-river) draining the pasture (3,587 ha), and two rivers draining a forest
(738 and 879 ha) in eastern Hokkaido, northern Japan. During higher river flow due to precipitation and thawing, the concentrations
of NO
3
−
, SO
4
2−
, K+, Fe, and Al increased, suggesting the relative importance of the shallow soil layer as their source. On the other hand, Na+, Mg2+, Ca2+, and Si decreased, suggesting the relative importance of the source in a deep soil layer. The concentrations of NO
3
−
, Cl−, SO
4
2−
, K+, Na+, Mg2+, Ca2+, and Fe were higher in the T-river than in the forest drainage waters, suggesting the contribution of the excretion components
from the milk cows. The Si concentration exhibited the opposite pattern. The concentrations of NO
3
−
, Cl−, SO
4
2−
, K+, Na+, Mg2+, Ca2+ (p<0.001), and Fe (p<0.05) in the T-river decreased after the confluence of the forest drainage waters, while Si concentration increased (p<0.001). The reason for the change in river chemistry was the confluence of the forest drainage waters. These findings suggested
the environmental role of the forest in the dilution of the polluted river.
Prof. S. Ohata, and Prof. H. Takeda, Graduate School of Agriculture, Kyoto University, facilitated this study. Prof. T. Sakai,
Graduate School of Informatics, Kyoto University, offered this study some convenience. Dr. M. Sakimoto, and Dr. M. Katsuyama,
Graduate School of Agriculture, Kyoto University, offered useful advise. 相似文献
16.
The study was carried out over a period of 1999–2003 in the Dupniański Stream catchment located in Silesian Beskid Mts. Region
(Southern Poland). Analysis of the chemical composition of bulk precipitation, throughfall, stemflow, surface flow, soil water
(horizontal + vertical and vertical penetration) and outflow water samples was performed. The complex data matrix with more
than 3,000 observations of water reaction, major anions (F−, Cl−, NO3
−, SO4
2−) and cations (NH4
+, Na+, K+, Ca2+, Mg2+, Fe2+, Mn2+ and Zn2+) were treated by regression modelling. The modelling approach took into account seasonal variability according to winter
and growing season, as well as chronosequence of spruce stands. The retention of considerable levels of contaminants by the
canopy, and their removal or washout from needles by rainfall caused changes in the concentration of anions and cations reaching
the soil surface compared to the concentrations in bulk precipitation. In the youngest stand, most elements except NH4
+, SO4
2− and K+ were retained in the canopy, and even H+ ions were neutralized. In the older stands, most elements increased in net throughfall fluxes, and the acidity increased
strongly. Soil water was slightly correlated with throughfall, while outflow water showed no correlations with the above ground
water flows, and seemed to depend mostly of the bedrock. 相似文献
17.
Chemical characteristics of forest soils subjected to long-term deposition of alkaline and acid air pollutants were analysed in spruce (Picea abies (L.) Karst.) stands in eastern Germany. Three forest sites along an emission gradient of 3, 6, and 15 km downwind of a coal-fired power plant were selected, representing high, intermediate, and low fly-ash input rates. Past emissions caused an accumulation of mineral fly-ash constituents in the organic layer, resulting in an atypically high mass of organic horizons of forest soils, especially in the F and H horizons. Total mass of organic layers at the site with heavy deposition loads was as high as 128 t ha–1, compared to 58 t ha–1 at the low input site. Fly-ash deposition significantly increased the pH values in the L, F and H horizons and mineral topsoil (0–10 cm). Significantly higher concentrations of NH4Cl-extractable cations (i.e. effective cation exchange capacities) and base saturations of >66% were found in the humic horizons at sites where the pH was increased due to the direct and indirect (i.e. higher proportions of deciduous trees) effects of fly-ash emissions. Stocks of basic cations were dominated by Ca2+ and decreased significantly along the fly-ash deposition gradient from 33.6 to 5.3 kmolc ha–1. Proportions of water-soluble basic cations out of the total potentially exchangeable (i.e. NH4Cl-extractable) basic cations generally increased in the forest soil with decreasing deposition loads following the cation exchange capacity and base saturation along the fly-ash gradient. Higher proportions of monovalent cations, such as K+ and Na+, were observed in the water extracts from fly-ash-affected forest soils, while the NH4Cl-extracts were dominated by bivalent cations, such as Ca2+ and Mg2+. These results suggest a greater leaching tendency for monovalent cations in these soils. Stocks of organic C and total N in the humus layer decreased from sites with high fly-ash deposition levels to sites with low levels, from 57.4 to 46.4 t C ha–1 and from 2.43 to 1.99 t N ha–1. The C/N ratios of the organic horizons varied from 22 to 25, revealing no distinct pattern along the fly-ash gradient. Measurements of hot-water-extractable and water-soluble organic C suggested a reduced availability or a faster decomposition of soil organic matter in soils with historically high fly-ash loads. 相似文献
18.
In Seong Choi Seung Gon Wi Se Ra Jung Darshan H. Patel Hyeun-Jong Bae 《Journal of Wood Science》2009,55(5):329-334
β-Glucosidase (β-1,4-D-glucoside glucohydrolase: EC.3.2.1.21) catalyzes the hydrolysis of β-glucosidic bonds between saccharides
and aryl or alkyl groups. A gene encoding β-glucosidase from Bacillus licheniformis KCTC 1918, an anaerobic spore-forming soil bacterium, was cloned and characterized. The structural gene for the β-glucosidase
consists of 1410 bp encoding 469 amino acid residues, and has a molecular weight of 53.4 kDa as estimated by sodium dodecyl
sulfate polyacrylamide gel electrophoresis with 12% separating gel. The enzyme activity was determined against pNPG as a substrate. The enzyme was optimally active at pH 6.0 (citrate-phosphate buffer) and 47°C. β-Glucosidase retained
100% of its original activity for 24 h. The activity of the enzyme was stimulated by glycerol and urea and was decreased by
Ca2+, Cu2+, Hg2+, Mg2+, and Mn2+. In particular, Cu2+ had the strongest negative effect on β-glucosidase activity. The purified β-glucosidase was active against pNPG and cellobiose. When the β-glucosidase was tested for cellulose hydrolysis, the supplement of β-glucosidase with cellulose
increased the glucose yield from pine wood powder by 139.8%. 相似文献
19.
１９９８年４月至１９９９年３月对广州市白云山马尾松林和常绿阔叶林、广州市龙眼洞马尾松林两试验点进行了酸雨的监测,并测定和分析了林内穿透雨物理量及化学量,旨在探讨酸雨对不同森林冠层养分淋溶规律的影响。结果表明：（１）广州市酸雨占次数的７９．７％或占降雨量的９５．１％。（２）酸雨通过林冠层后,ｐＨ值明显增加。（３）在马尾松林和常绿阔叶林中,某些单次降雨出现ＳＯ４＾２－、ＮＯ３＾－、ＮＨ４＾＋Ａｌ＾３＋、Ｎａ＾＋的负淋溶现象,说明森林对这些离子（特别是ＮＯ３＾－、Ａａ＾３＋）具有吸收作用;阔叶林全年的ＮＯ３＾－和Ａｌ＾３＋净淋溶为负值,说明阔叶林比马尾松林对这两种离子具有更强的吸收能力。（４）雨水酸度增加（即ｐＨ值减小）,明显提高阳离子Ｃａ＾２＋、Ｍｇ＾２＋、Ｋ＾＋和Ｎａ＾＋冠层淋溶面分率。（５）ＮＨ４＾＋、ＳＯ４＾ 相似文献
20.
Conversion of native forest ecosystem to cropland has considerably degraded the soil nutrient levels in the Bale Mountains, south-eastern highlands of Ethiopia. This study investigated the effects of land use change through conversion of native forest to cropland and/or grazing land on soil pH (H2O), base cations (Ca2+, Mg2+, K+, Na+), CEC and percentage base saturation (PBS) in three adjacent land-use types: cropland, grazing land and native forest. A total of 108 soil samples (3 replications × 3 land-use types × 4 profiles × 3 soil depth layers, 0–0.2, 0.2–0.4 and 0.4–1.0 m) were collected for laboratory analyses. Results showed that soil pH, Na+ and K+, CEC, and PBS varied significantly with respect to land use and soil depth while Ca2+and Mg2+ varied with soil depth (ρ < 0.05). Conversion of native forest ecosystem to cropland during a 15-year period significantly increased soil pH and PBS while reducing Na+ and K+. The CEC in the cropland was reduced by 37.7% (2.6% per annum) compared to the native forest, which could be attributed to the decline in organic matter concentrations. If such rapid declines in soil nutrient concentrations continue unabated, the soils will reach at the point of no return within a few decades. Although the effect of grazing on most of the properties was found to be minimal, adapting the number of stock to the carrying capacity of the land and thereby enhancing the natural regeneration, combined with proper cropland management practices could help restoring soil nutrients for sustainable agricultural production and ecosystem functions. 相似文献