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1.
Ten clonal units of Carex pseudocuraica growing in four different microhabitats (perennial flooded ditch water,perennial flooded ditch sediment,seasonal flooded ditch sediment and perennial flooded soil) of the Sanjiang Plain,Northeast China,were collected randomly for phenotypic plasticity analysis.Iron content,chemical and physical properties of substrates and the total Fe of nine plant modules were measured as well.The results show that the performance of the C.pseudocuraica is affected by the microhabitat,with the greatest performance score in perennial flooded ditch water,and the lowest in perennial flooded soil.The biomass allocation indexes indicate that much more mass is allocated to stems and roots to expand colonization area.The distribution of the total Fe in plant modules appears as pyramids from the tip to the root,while marked differences are observed in the distribution proportion of stems,tillering nodes and roots that are allometrically growing.Iron transfer from substrates to the plant is mainly controlled by the substrate type.The differences of iron distribution and transfer in the plant in different microhabitats are attributed to the iron contents of the substrates as well as the phenotypic plasticity of the plant.  相似文献   

2.
The patterns of C:N:P stoichiometry across ecosystems are important in understanding biogeochemical processes. The stoichiometry of nutrients at the leaf and root level have been reported previously, but relationships of other plant organs, such as stems and the reproductive organs, remain unclear. We collected 228 samples of leaves, roots, stems and reproductive organs from 11 common plant species at 25 sites on the Tibetan Plateau to explore the relationships of C:N:P stoichiometry both within and across plant organs. The average C concentrations in the roots, leaves, stems and reproductive organs were 427.32, 410.51, 421.11 and 416.72 mg g~(-1), respectively. The shoot tissues(leaves, stems and reproductive organs) had significantly higher N and P concentrations than the roots. The N and P concentrations had a significant positive correlation within the same organ. The nutrient concentrations(N and P) and nutrient ratios(C:N, C:P and N:P) were significantly correlated across all pairwise organ combinations. Our data suggest that alpine perennial herbs share similar evolutionary histories and have constrained patterns of covariation for C concentrations, with differential patterns for N and P stoichiometry across organs. Our data also indicate that covarying sets of nutrient traits are consistent across environments and biogeographical regions and demonstrate convergent evolution in plant nutritional characteristics in extreme alpine environments.  相似文献   

3.
Investigation of phosphorus (P) sorption-desorption characteristics of drainage ditch sediments is important for better understanding on sediment P transport behaviors in ditches. Surface ditch sediment samples were collected from headwater sub-catchment of forestland, sloping cropland, paddy field, and residential area in a representative catchment in the central Sichuan Basin. These sediment samples were used for determination of P sorption-desorption characteristics by a batch equilibrium technique. Results showed that the maximum P sorption capacities (Qm) in the sediments ranged from 159.7 to 263.7 mg/kg, while higher Qm were observed in the ditch sediments from the paddy fields. The Qm was significantly and positively correlated with oxalate-extractable Fe and Al oxides (r=0.97 and 0.98, p < 0.01), clay fraction (r = 0.78, p < 0.05) and organic matter (r = 0.95, p < 0.01). Sediment pH, clay and organic matter influenced the P sorption through amorphous Fe and Al oxides. CaCO3 content was negatively correlated with the Qm (r = -0.83, p < 0.05), implying that saturated CaCO3 (> 50 g/kg) would not increase P sorption capacity in the ditch sediments. The ditch sediments featured a linear desorption curve, suggesting that P release risk would be enhanced with the increase of the P adsorption. The P desorption rate was positively correlated with Olsen P (r = 0.94, p < 0.01), but negatively related to the fine particle-size fractions (r = -0.92, p < 0.01), the sum of the amorphous Fe and Al oxides (r = -0.67, p < 0.05) and the P sorption capacity (r = -0.59, p < 0.05). The ditch sediments from residential area had a higher P release risk than that from the other ditches of forestland, sloping cropland and paddy field. The P sorption index (PSI) derived from single-point measurement was significantly correlated with the P sorption capacity (r = 0.99, p < 0.01), and could be used for estimating Qm as 1.64 times PSI plus 24.0 (Qm = 1.64 PSI + 24.0) for similar sediments with highly calcareous soils and sediments. Ditch cleaning and sediment removal for the ditch in residential area were recommended in this area to reduce the P release risk.  相似文献   

4.
Accumulation of metals in both sediments and Phragmites australis organs was studied. Samples were collected from seven stations located in Anzali wetland, Iran. The samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that concentration of the studied metals (except As and Cd) were higher in sediments than in P. australis organs. Metal accumulation was found to be significantly (P <0.05) higher in roots than in above-ground organs of P. australis. The bioaccumulation factor (BAF) and the transfer factor (TF) also verified the highest rate of metal accumulation in roots and their reduced mobility from roots to the above-ground organs. Pearson correlation coefficient showed significant relationships between metal concentrations in sediments and those in plant organs. It should be pointed out that sediment and plant samples exhibited higher metal concentrations in eastern and central parts than in western and southern parts of the wetland. The mean concentrations of all studied elements (except for Fe, V and Al) were higher in these sediment samples than in the Earth’s crust and shale. High accumulation of metals in P. australis organs (roots and shoots) is indicative of their high bioavailability in sediments of the wetland. The correlation between metal concentrations in sediments and in P. australis indicates that plant organs are good bioindicators of metal pollution in sediments of Anzali wetland.  相似文献   

5.
Our study on the horizontal and vertical distribution, change pattern, and migration form origin of iron and manganese and the factors affecting them in surface sediment in the western Mid-Pacific and in columnar sediment of station L 2032 is introduced. The author inferred the lysocline and compensation depth of the ocean by using the content changes of Fe and Mn; differentiated rapidly sedimentation types by using the difference of Fe and Mn contents, estimated tentatively their contents in different sediments by using the dyeability of Fe and Mn. The author notes that the economically valuable Fe−Mn nodules can be formed during Fe−Mn deposition in the ocean and that in studies on Fe and Mn deposition, the affecting factors should be analyzed comprehensively.  相似文献   

6.
Accumulation of metals in both sediments and Phragmites australis organs was studied. Samples were collected from seven stations located in Anzali wetland, Iran. The samples were analyzed by inductively coupled plasma mass spectrometry(ICP-MS). The results showed that concentration of the studied metals(except As and Cd) were higher in sediments than in P.australis organs. Metal accumulation was found to be signifi cantly(P 0.05) higher in roots than in above-ground organs of P.australis. The bioaccumulation factor(BAF) and the transfer factor(TF) also verifi ed the highest rate of metal accumulation in roots and their reduced mobility from roots to the above-ground organs. Pearson correlation coeffi cient showed signifi cant relationships between metal concentrations in sediments and those in plant organs. It should be pointed out that sediment and plant samples exhibited higher metal concentrations in eastern and central parts than in western and southern parts of the wetland. The mean concentrations of all studied elements(except for Fe, V and Al) were higher in these sediment samples than in the Earth's crust and shale. High accumulation of metals in P. australis organs(roots and shoots) is indicative of their high bioavailability in sediments of the wetland. The correlation between metal concentrations in sediments and in P. australis indicates that plant organs are good bioindicators of metal pollution in sediments of Anzali wetland.  相似文献   

7.
Phenotypic plasticity and/or pollinator-mediated selection may be responsible for the changes in floral traits of plants when they are forced to live in new conditions. Although the two events could be independent, we hypothesized that phenotypic plasticity in floral traits might help to coordinate plant-pollinator interactions and enhance plant reproductive success in changing habitats. To test this hypothesis, we investigated floral traits and pollination on three natural populations of a lousewort (Pedicularis siphonantha) ranging at different elevations, as well as two downward transplanted populations in Shangeri-La County and Deqin County, northwest Yunnan, China. The results indicated that floral traits, i.e. phenology, longevity, display size, corolla tube length and pollen production differed significantly among populations. Moreover, or the two transplanted populations, floral traits diverged from their original populations, but converged to their host populations. Although the phenotypic plasticity in floral traits might be a rapid response to abiotic factor such as warmer environment, the changes in floral traits were found to be well adapted to pollination environment of the host population. Compared with plants of their original habitats in higher elevation, the transplanted individuals advanced flowering time, shortened flower longevity, reduced floral display size and pollen production, received higher visiting frequency and yielded more seeds. These findings suggested that phenotypic plasticity of floral traits might help plants adjust their resource allocation strategy between preand post-pollination stages in response to harsh or temperate conditions, which might correspondingly meet a pollinator-poor or hyphen rich environment. This would be beneficial for the widely-distributed species to adapt to various environmental changes.  相似文献   

8.
To increase the cell concentration and the accumulation of astaxanthin in the cultivation of Haematococcus pluvialis, effects of different iron eleetrovalencies (Fe2+-EDTA and Fe3+-EDTA) and species (Fe-EDTA, Fe(OH)32x and FeC6H5O7) addition on cell growth and accumulation of astaxanthin were studied. Results show that different iron electrovalencies have various effects on cell growth and astaxanthin accumulation of H. pluvialis. Compared with Fe3+-EDTA, Fe2+-EDTA stimulate more effectively the formation of astaxanthin. The maximum astaxanthin content (30.70 mg/g biomass cell)was obtained under conditions of 18 μmol/L Fe2+-EDTA, despite the lower cell density (2.3x105 cell/ml)in such condition. Fe3+-EDTA is more effective than Fe2+-EDTA in improving the cell growth. Especially,the maximal steady-state cell density, 2.9x105 cell/ml was obtained at 18 μmol/L Fe3+-EDTA addition. On the other hand, all the various species of iron (EDTA-Fe, Fe(OH)32x, FeC6H5O7) are capable to improve the growth of the algae and astaxanthin production. Among the three iron species, FeC6H5O7 performed the best. Under the condition of a higher concentration (36 μmol/L) of FEC6H5O7, the cell density and astaxanthin production is 2 and 7 times higher than those of iron-limited group, respectively. The present study demonstrates that the effects of the stimulation with different iron species increased in the order of FeC6H5O7, Fe(OH)32x/x and EDTA-Fe.  相似文献   

9.
A novel method for on-site determination of trace iron was developed using membrane preconcentration and spectrophotometric detection. Fe(Ⅱ)-ferrozine complex was reacted with cetyltrimethylammonium bromide (CTAB) to form a Fe(Ⅱ)-ferrozine-CTAB paired compound, which was collected on a membrane by filtration under vacuum. The membrane was immersed in 2 mL of ethanol-nitric acid and the absorbance of the solution measured for quantitative analysis. Various factors affecting the iron collection and determination were investigated. With different sample preconcentration volumes, the range of determination was broadened to 0.5-120 g/L. The detection limit of this method reached 0.19 g/L and the recoveries were between 97.2 and 109% when the concentration enrichment was about 45. The relative standard deviation (n = 7) was 1.9% for samples containing 10 g/L Fe. Twelve seawater samples were analyzed on-site using the proposed method, and two were also analyzed in inductively coupled plasma mass spectrometry. No significant difference was shown between the two methods by the Student’s t-test. The method has also been used on-site for iron enrichment experiments with phytoplankton and concluded to be simple, accurate and inexpensive.  相似文献   

10.
南任铁矿床位于莱州-安丘铁成矿带西北部,对其矿床成因认识存在较多争议。矿区内地层广布,构造、岩浆岩不发育。铁矿体呈透镜状产于滹沱纪粉子山群小宋组的底部层位,无穿插或交代围岩现象;围岩蚀变以蛇纹石化、绿泥石化为主,愈近矿体矿化蚀变愈强。矿石矿物以磁铁矿为主,少量黄铁矿、黄铜矿;脉石矿物主要为蛇纹石、绿泥石。矿石的结构构造主要为浸染状构造,半自形—他形粒状结构。岩矿石稀土元素含量表明磁铁矿主要为火山深成岩浆结晶分异形成,部分与火山沉积作用有关;磁铁矿化学成分特征也反映了这一点,综合认为其成因可能属海相火山岩型之火山岩浆-热液和火山沉积复合类型。在此基础上,总结了莱州-安丘铁成矿带上不同成因铁矿床的分布规律,为今后该地区铁矿勘查指明了方向。  相似文献   

11.
安丘市夹河套铁矿属沉积变质型磁铁矿床。铁矿产于古元古代粉子山群中，受小宋组二段底部含铁岩系的控制。通过对成矿地质背景及矿床地质特征的分析，指出现已圈定的2个铁矿体在其深部仍未圈闭，且夹河套西南、东北区段及潍河东岸等地具有较大范围的磁异常，从而为进一步选择靶区，扩大资源远景提供了依据。  相似文献   

12.
The distribution characteristics of methyl mercury in Rana chensinensis and water, sediment and soil in gold-mining areas of the upper reaches of the Songhua River, China were studied by field sampling and laboratory testing. The results show that the methyl mercury contents in water, sediment and soil in gold-mining areas are much higher than those in the control site, indicating that gold-mining activities intensify the methyl mercury pollution in the study area. Methyl mercury contents are in a descending order of sediment > soil > water in the environment, and in a descending order of brain > viscera > muscle > skin in Rana chensinensis. There are significant correlation between methyl mercury contents in Rana chensinensis and those in water and sediment. In particular, the methyl mercury content in the skin of Rana chensinensis is positively correlated with those in water and sediment in spring. Therefore, skin is one of main intake pathways for methyl mercury due to its high permeability.  相似文献   

13.
张马屯铁矿为一夕卡岩型磁铁矿床，水文地质条件极其复杂，单一的防治水方法难以达到采矿生产的要求。在长期探索矿山防治水的基础上，采用同水平疏干法对张马屯铁矿地下水脉管式径流进行试验，取得了完全疏干的效果，为深井大水矿山探索出一条综合治理的途径。  相似文献   

14.
This study reports the geochemical characteristics of zinc (Zn), copper (Cu), lead (Pb), nickel (Ni), mercury (Hg), iron (Fe), and manganese (Mn) in the riparian sediment pore water of the Songhua River, Northeast China. In total, 36 pore water samples and 18 surface water samples from three typical sections were collected and analyzed in June 2009. Cluster analysis of heavy metals was performed to analyze the pollution sources of the metals. Results showed that Hg concentrations in the pore water were greater than those in the surface water, indicating a potential ability of Hg release from riparian sediment system to river water. However, concentrations of Fe and Mn in the surface water were greater than those in the pore water, demonstrating that the microenvironments of riparian and riverbed sediment systems were quite different. Variations of Zn, Cu, Pb and Ni between the surface and the pore water were different in each section. Most metals had similar horizontal and profile distribution characteristics in the three sections except for Zn and Ni. Hg, Fe and Mn concentrations in the pore water increased gradually with the increase in horizontal distance from water body, in contrast to this, Cu decreased, and Pb presented a fluctuating trend. With the increase in depth, Pb and Fe, Cu and Mn showed the same trends, and Hg showed a variable trend. The above distribution characteristics could mainly be attributed to the properties and the interactions of metals, pH and oxidation-reduction conditions, and the complex pollution sources and hydrologic regime in history. The probable sources of metals include the historical and ongoing discharge of industrial wastewater, mining activities, sewage irrigation for agricultural production, and atmospheric deposition from coal-fired plants.  相似文献   

15.
The multi-level ditch system developed in the Sanjiang Plain, Northeast China has sped up water drainage process hence transferred more pollutants from farmlands into the rivers of this region. Understanding the seasonal dynamics of nitrogen (N) and phosphorus (P) transportation in the ditch system and the role of different ditch size is thus crucial for water pollution control of the rivers in the Sanjiang Plain. In this study, an investigation was conducted in the Nongjiang watershed of the Sanjiang Plain to study the nutrient variation and the correlation between water and sediments in the ditch system in terms of ditch level. Water and sediments samples were collected in each ditch level in growing season at regular intervals (once per month), and TN, NO3 −N, NH4 +-N, TP, and PO4 3−-P were analyzed. The results show that nutrient contents in water were higher in June and July, especially in July, the contents of TN and TP were 3.21 mg/L and 0.84 mg/L in field ditch, 4.04 mg/L and 1.06 mg/L in lateral ditch, 2.46 mg/L and 0.70 mg/L in branch ditch, 1.92 mg/L and 0.63 mg/L in main ditch, respectively. In August and September, the nutrient contents in the water were relatively lower. The peak value of nutrient in ditch water had been moving from the field ditch to the main ditch over time, showing a remarkable impact of ditch system on river water environment. The nutrient transfer in ditch sediments could only be found in rainfall season. Nutrient contents in ditch sediment had effect on that in ditch water, but nutrients in ditch water and sediments had different origination. Ditch management in terms of the key factors is hence very important for protecting river water environment.  相似文献   

16.
There is limited information available on CO2 concentration and flux over marsh. The objective of this work was to characterize CO2 concentration and flux within and above marsh plant (Carex lasiocarpa Ehrh. and C. pseudocuraica F. Schm) canopy at heights 0.5, 1.0 and 1.5 m. CO2 concentration was measured sequentially every 3 hours by using an infrared gas analyzer. Soil and air temperature, wind speed, net radiation and soil heat flux were also measured simultaneously. Extremely daily minimum and maximum CO2 concentration ranged from 250 to 754 μmd/mol for the 4-year work. The typical minimum and maximum values ranged from 314 to 464 μmol/mol at the height of marsh plant (about 0.5 m) during the fruiting period and mature date. The seasonal changes in CO2 concentration show that the minimum CO2 concentration occurred in the fruiting period and mature date, and both of their minimum values were 314 μmol/mol. This illustrates that CO2 consumed by photosynthesis was stable during the period. The flux of CO2 can be thought as a turbulent diffusion phenomenon. By micrometeorological methods, the diurnal CO2 fluxes were measured in the flowering period, fruiting period, early mature date, late mature date and yellow-ripe stage. Their values were −0.18, 38.15,24.13,10.9 and 4.91 μmol/mol respectively.  相似文献   

17.
Fe, Chlorophyll (Chl) and total nitrogen (TN) content in tissues were measured in Fe-deficient cultures ofUlva. pertusa over a period of 60 days. Photosynthetic carbon fixation rates were studied at the start of and 30 days after Fe-deficiency culture, when the effects of Fe-deficiency on the ultrastructure were also analyzed. The iron content in tissue decreased exponentially during Fe-deficiency (from 726.7 to 31.6 μg/gdw) and simultaneously Chl and TN content declined to 4.35% and 59.9% of their original levels respectively. Maximum carbon fixation rate (50–250 μmol/m2 s) under Fe-deficiency decreased significantly compared with the control (p<0.01) and was 13.6 to 0.365 μg C/cm2 h. Photosynthesis in Fe-deficient cells became light-saturated at lower irradiance than that in control. Ultrastructural observations of Fe-deficient cells showed reductions in chloroplast number, some degeneration of lamellar organization, an increase in vacuolar area, a decrease in mitochondrial matrix density, and variation in accumulation body number and morphology. During Fe-deficiency, the algae growth rate continued to decline and after 6 weeks of iron deficiency, no further growth was detectable. These suggested that the lower growth rate ofUlva. pertusa under Fe-deficiency could be due mainly to nitrogen utilization and inhibition of photosynthesis. This project No. 39725023 supported by NSFC for Talented Youths and the Project under the Major State Basic Research of China (Grant No. G1999012011).  相似文献   

18.
To increase the cell concentration and the accumulation of astaxanthin in the cultivation of Haematococcus pluvialis, effects of different iron electrovalencies (Fe2+-EDTA and Fe3+-EDTA) and species (Fe-EDTA, Fe(OH)x32x and FeC6H5O7) addition on cell growth and accumulation of astaxanthin were studied. Results show that different iron electrovalencies have various effects on cell growth and astaxanthin accumulation of H. pluvialis. Compared with Fe3+-EDTA, Fe2+-EDTA stimulate more effectively the formation of astaxanthin. The maximum astaxanthin content (30.70 mg/g biomass cell) was obtained under conditions of 18 μmol/L Fe2+-EDTA, despite the lower cell density (2.3×105 cell/ml) in such condition. Fe3+-EDTA is more effective than Fe2+-EDTA in improving the cell growth. Especially, the maximal steady-state cell density, 2.9×105 cell/ml was obtained at 18 μmol/L Fe3+-EDTA addition. On the other hand, all the various species of iron (EDTA-Fe, Fe(OH)x32x, FeC6H5O7) are capable to improve the growth of the algae and astaxanthin production. Among the three iron species, FeC6H5O7 performed the best. Under the condition of a higher concentration (36 μmol/L) of FeC6H5O7, the cell density and astaxanthin production is 2 and 7 times higher than those of iron-limited group, respectively. The present study demonstrates that the effects of the stimulation with different iron species increased in the order of FeC6H5O7, Fe(OH)x32x and EDTA-Fe. Supported by Xiamen Scientific and Technologic Projects (No. 3052Z20031086), Xiamen University Alumni Association Foundation in Singapore, and the First National College Students Innovative Experimental Project  相似文献   

19.
1　IntroductionForthepast 1 5years,muchattentionofoceanographershasbeenfocusedontheroleofironinlimiting phytoplankton productivityinthehigh nutrient ,low chlorophyll(HNLC)regions.OnboardshipironenrichmentincubationshavebeencarriedoutinthethreewellknownHNLCregions :notablyequatorialPacificOcean ,subarcticPacificO ceanandSouthernOcean (seereferencesinTable 1 ) .Theinsituironenrichmentexper imentshavebeenaccomplishedintheequatorialPacific (IronEx1in 1 993 (Wells 1 994)andIronEx2in 1 996(…  相似文献   

20.
山东昌邑东部地区铁矿分布在莱州-安丘磁异常铁成矿带内,该区发育着古元古代粉子山群小宋组及荆山群野头组祥山段含铁岩系,磁铁黑云变粒岩、磁铁石英岩、磁铁大理岩、磁铁蛇纹石化大理岩等含铁岩层发育在这2套含铁岩系中。目前,已发现有毛家寨、南任、常家屯及东辛庄-莲花山等矿床。铁矿体呈层状、似层状及透镜状,矿体产状与围岩基本一致,矿体长多为200~700m,厚多为2~15m,延深多为60~300m。矿石品位多为27%~33%,属酸性矿石。该矿床属于受含铁沉积建造及变质作用控制的变质沉积型矿床。  相似文献   

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