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1.
增硝营养对水稻不同生育时期生长及氮素吸收同化的影响   总被引：14，自引：0，他引：14  
The effect of nitrate （NO3^-） on rice （Oryza sativa L.） growth as well as N absorption and assimilation during different growth stages was examined using three typical rice cultivars. Dry weight, yield, N uptake, nitrate reductase activity （NRA） in leaves, and glutamine synthetase activity （GSA） in roots and leaves during their entire growth periods, as well as the kinetic parameters of ammonium （NH4^＋） uptake at the seedling stage, were measured with solution culture experiments. Results indicated that addition of NH4^＋-N and NO3^-N at a ratio of 75：25 （NH4^＋＋NO3^- treatment） when compared with that of NH4^＋-N alone （NH4^＋ treatment） increased the dry weight of ‘Nanguang＇ cultivar by 30% and ‘Yunjing 38＇ cultivar by 31%, and also increased their grain yield by 21% and 17%, respectively. For the four growth stages, the total N accumulation in plants increased by an average of 36% for ‘Nanguang＇ and 31% for ‘Yunjing 38＇, whereas the increasing effect of NO3^- in the ‘4007＇ cultivar was only found at the seedling stage, in the NH4^＋＋NO3^- treatment compared to the NH4^＋ treatment, NRA in the leaves increased by 2.09 folds, and GSA increased by 92% in the roots and 52% in the leaves of the three cultivars. NO3^- supply increased the maximum uptake rate （Vmax） in the ‘Nanguang＇ and ‘Yunjing 38＇ cultivars, reflecting that the NO3^- itself, not the increasing N concentration, increased the uptake rate of NH4^＋ by rice. There was no effect on the apparent Michaelis-Menten constant （Kin） of the three cultivars. Thus, some replacement of NH4^＋ with NO3^-could greatly improve the growth of rice plants, mainly on account of the increased uptake of NH4^＋ promoted by NO3^-, and future studies should focus on the molecular mechanism of the increased uptake of NH4^＋ by NO3^-.  相似文献   

2.
氮对水稻铵转运蛋白表达的调控   总被引：3，自引：0，他引：3  
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3.
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4.
Ammonium（NH＋4） is the main nitrogen（N） form for rice crops, while NH＋4near the root surface can be oxidized to nitrate（NO-3）by NH＋4-oxidizing bacteria. Nitrate can be accumulated within rice tissues and reused when N supply is insufficient. We compared the remobilization of NO-3stored in the tissue and vacuolar between two rice（Oryza sativa L.） cultivars, Yangdao 6（YD6, indica）with a high N use efficiency（NUE） and Wuyujing 3（WYJ3, japonica） with a low NUE and measured the uptake of NO-3, expression of nitrate reductase（NR）, NO-3transporter genes（NRTs）, and NR activity after 4 d of N starvation following 7-d cultivation in a solution containing 2.86 mmol L-1NO-3. The results showed that both tissue NO-3concentration and vacuolar NO-3activity were higher in YD6 than WYJ3 under N starvation. YD6 showed a 2- to 3-fold higher expression of OsNRT2.1 in roots on the 1st and 4th day of N starvation and had significantly higher values of NO-3uptake（maximum uptake velocity, Vmax） than the cultivar WYJ3.Furthermore, YD6 had significantly higher leaf and root maximum NR activity（NRAmax） and actual NR activity（NRAact） as well as stronger root expression of the two NR genes after the 1st day of N starvation. There were no significant differences in NRAmax and NRAact between the two rice cultivars on the 4th day of N starvation. The results suggested that YD6 had stronger NRA under N starvation, which might result in better NO-3re-utilization from the vacuole, and higher capacity for NO-3uptake and use, potentially explaining the higher NUE of YD6 compared with WYJ3.  相似文献   

5.
A comparative study was conducted to determine the NH4^＋ and NO3^- concentrations in soil profiles and to examine the net nitrogen （N） mineralization and nitrification in adjacent forest, grassland, and cropland soils on the Tibetan Plateau. Cropland soil showed significantly higher inorganic N concentrations in soil profiles compared with forest and grassland soils. NO3^- -N accounted for 70%-90^ of inorganic N in cropland soil, while NH4^＋ -N was the main form of inorganic N in forest and grassland soils. The average net N mineralization rate at 0 20 cm depth was approximately twice in cropland soil （1.48 mg kg^-1 d^-1） as high as in forest （0.83 mg kg^-1 d^-1） or grassland soil （0.72 mg kg^-1 d^-1）. Cropland showed strong net nitrification, with the net rate almost equal to the total net N mineralization. Urea addition stimulated soil respiration, particularly in forest soil. Most urea-N, however, remained as NH4^＋ in forest and grassland soils, while NO3^- was the main form of inorganic N to increase in cropland soil. Higher rates of net nitrification in cropland soils suggest that land use change on the Tibetan Plateau may lead to high N losses through nitrate leaching.  相似文献   

6.
Rapid nitrogen（N） transformations and losses occur in the rice rhizosphere through root uptake and microbial activities. However,the relationships between rice roots and rhizosphere microbes for N utilization are still unclear. We analyzed different N forms（NH＋4,NO-3, and dissolved organic N）, microbial biomass N and C, dissolved organic C, CH4 and N2O emissions, and abundance of microbial functional genes in both rhizosphere and bulk soils after 37-d rice growth in a greenhouse pot experiment. Results showed that the dissolved organic C was significantly higher in the rhizosphere soil than in the non-rhizosphere bulk soil, but microbial biomass C showed no significant difference. The concentrations of NH＋4, dissolved organic N, and microbial biomass N in the rhizosphere soil were significantly lower than those of the bulk soil, whereas NO-3in the rhizosphere soil was comparable to that in the bulk soil. The CH4 and N2O fluxes from the rhizosphere soil were much higher than those from the bulk soil. Real-time polymerase chain reaction analysis showed that the abundance of seven selected genes, bacterial and archaeal 16 S rRNA genes, amoA genes of ammonia-oxidizing archaea and ammonia-oxidizing bacteria, nosZ gene, mcrA gene, and pmoA gene, was lower in the rhizosphere soil than in the bulk soil, which is contrary to the results of previous studies. The lower concentration of N in the rhizosphere soil indicated that the competition for N in the rhizosphere soil was very strong, thus having a negative effect on the numbers of microbes. We concluded that when N was limiting, the growth of rhizosphere microorganisms depended on their competitive abilities with rice roots for N.  相似文献   

7.
Ammonium fixation and adsorption experiments were conducted to study the effect of potassium on ammonium fixation into interlasyer of vermiculite and ammonium adsorption at the surface of vermiculite both in the binary (NH4^ -Ca^2 ) and ternary (NH4^ -Ca^2 ) ystems.In the ammonium fixation experiment,5 mmol NH4^ kg^-1 was added alone,or after,before of simultaneously with 5 mmol K^ kg^-1 to the vermiculite (Vermiculite:solution=1:1),and the incubation was conducted for 3 days under constant 20℃，In the adsorption experiment ,after addition of 10 mmol Ca^2 L^-1 as matrix ions ,either,NH4^ alone with a concentration series from 0.1 to 5.0 mmol NH4^ L^-1(binary exchange system of NH4^ and Ca^2 )of NH4^ together with 5 mmol K^ L^-1(ternary exchange system of NH4^ ,K^ and Ca^2 ) was added to vermiculte at a vermiculite to solution ratio of 1:10 for 24-h equlibrium.The results of the fixtion experiment showed that the presence of K^ increased NH4^ fixation for all the treatments,regardless of the addition orders.For ammonium adsorption a linear realtionship between activtiy ratios of NH4^ to Ca^2 and Mg^2 in the equilibrium solutions(ARNH4)and incereases of exchangeable NH4^ at the surface of vermiculite after 24 h equilibrium (△Ex-NH4^ )was shown for almost the whole concentration ranges tested.Compared With the binary system ,the slope of the curve of the ternary system was steeper,indicaitng a more intensive adsorption of NH4^ in the presence of K^ ,It was demonstrated that K^ did not reduce the ammonium fixation into the interlayer and ammonium adsorption at the surface of vermiculite ,which indicated that, under the experimental conditions of this study,K^ did neither occupy the sites for NH4^ -fixation in the interlayer nor the sites for NH4^ -adsorption at the surface of vermiculite.  相似文献   

8.
缺铁水稻根表铁膜对硒的转运和吸收的影响   总被引：2，自引：0，他引：2  
Under anaerobic conditions, ferric hydroxide deposits on the surface of rice roots and affects uptake and translocation of certain nutrients. In the present study, rice plants were cultured in Fe-deficient or sufficient solutions and placed in a medium containing selenium （Se） for 2 h. Then, FeSO4 was added at the various concentrations of 0, 10, 40, or 70 mg L-1 to induce varying levels of iron plaque on the root surfaces and subsequent uptake of Se was monitored. The uptake of Se was inhibited by the iron plaque, with the effect proportional to the amount of plaque induced. The activity of cysteine synthase was decreased with increasing amounts of iron plaque on the roots. This may be the important reason for iron plaque inhibition of Se translocation. At each level of iron plaque, Fe-deficient rice had more Se than Fe-sufficient rice. Furthermore, with plaque induced by 20 mg Fe L-1, plants from Fe-deficient media accumulated more Se than those from Fe-sufficient media, as the Se concentration was increased from 10 to 30 or 50 mg L^-1. We found that phytosiderophores, highly effective iron chelating agents, could desorb selenite from ferrihydrite. Root exudates of the Fe-deficient rice, especially phytosiderophores in the exudates, could enhance Se uptake by rice plants with iron plaque.  相似文献   

9.
A soil column method was used to compare the effect of drip fertigation （the application of fertilizer through drip irrigation systems, DFI） on the leaching loss and transformation of urea-N in soil with that of surface fertilization combined with flood irrigation （SFI）, and to study the leaching loss and transformation of three kinds of nitrogen fertilizers （nitrate fertilizer, ammonium fertilizer, and urea fertilizer） in two contrasting soils after the fertigation. In comparison to SFI, DFI decreased leaching loss of urea-N from the soil and increased the mineral N （NH4^＋-N ＋ NO3^--N） in the soil. The N leached from a clay loam soil ranged from 5.7% to 9.6% of the total N added as fertilizer, whereas for a sandy loam soil they ranged between 16.2% and 30.4%. Leaching losses of mineral N were higher when nitrate fertilizer was used compared to urea or ammonium fertilizer. Compared to the control （without urea addition）, on the first day when soils were fertigated with urea, there were increases in NH4^＋-N in the soils. This confirmed the rapid hydrolysis of urea in soil during fertigation. NH4^＋-N in soils reached a peak about 5 days after fertigation, and due to nitrification it began to decrease at day 10. After applying NH4^＋-N fertilizer and urea and during the incubation period, the mineral nitrogen in the soil decreased. This may be related to the occurrence of NH4^＋-N fixation or volatilization in the soil during the fertigation process.  相似文献   

10.
集约水稻系统下施肥对土壤有机氮形态及供氮的影响   总被引：6，自引：0，他引：6  
Changes of soil organic nitrogen forms and soil nitrogen supply under continuous rice cropping system were investigated in a long-term fertilization experiment in Jinhua, Zhejiang Province, China. The fertilizer treatments included combination of P-K, N-K, N-P, and N-P-K as well as the control. After six years of continuous double-rice cropping, total soil N and hydrolysable N contents remained stable in plots with N treatments, while the hydrolysable N contents were substantially reduced in those plots without N application. Compared to the unbalanced fertilization treatments, P and K increased the percentage of hydrolysable ammonium N in the total soil N with the balanced application of N, and also maintained higher rice grain yields and nitrogen uptake. Grain yield was positively correlated with total N uptake （r = 0.875^＊＊）, hydrolysable N （r = 0.608^＊＊）, hydrolysable ammonium N （r = 0.560^＊＊） and the hydrolysable unknown N （r = 0.417^＊＊）. Total N uptake was positively correlated with hydrolysable N （r = 0.608^＊＊）, hydrolysable ammonium N （r = 0.440^＊＊） and hydro, lysable unknown N （r = 0.431^＊＊）. Soil nutrient depletion and/or unbalanced fertilization to rice crop reduced N content in soil microbial biomass, and therefore increased C/N ratio, suggesting a negative effect on the total microbial biomass in the soil.  相似文献   

11.
To understand the geochemical characteristics of iron and sulfur and the extent of iron-sulfide minerals influencing heavy metal behaviour in metal-polluted sediments of Talhu Lake, two sites, in Meiliang Bay （ML） and Wuli Lake （WL）, were selected to study the fractionation of iron, sulfur and related heavy metals. There were relatively high concentrations of Fe^2＋ and low concentrations of total S^2- in porewaters, indicating that conditions in these sediments favored iron reduction. The concentrations of acid volatile sulfides in sediments were 1.9-9.6 μmol g^-1 at ML and 1.0-11.7 μmool g^-1 at WL, both in the range of values detected in unpolluted lakes. Pyrite-S was 10.2-49.4 μmol g^-1 at ML and 10.3- 33.0 μmol g^-1 at WL, accounting for more than 69% of the reduced inorganic sulfur at both sites. The low degree of sulphidization （〈 14%） and pyritization （〈 10%） indicate that sulfate may be the limiting factor for pyrite formation. The extractability of Mn, Cu, Pb, Zn, Ni, and Cr in sediments all suggest that sulfides are not the major binding phase for these metals during early diagenesis. Sulfur may play a modest role in the geochemistry of iron and traced metals in the sediments.  相似文献   

12.
Estuarine sediments are the repository for a wide range of contaminants. Anthropogenic impacts and variations in the belowground biomass of salt marsh plants potentially select for different sediment microbial communities with different functional capabilities, including the ability to biotransform anthropogenic contaminants. There are large differences in both root morphology and the amount of fine root biomass of Spartina alterniflora and Phragmites australis; Spartina is the species commonly used to replace Phragmites in northeastern US salt marsh restoration projects. Our study compared the effect of these two macrophyte species on sediment microbial communities responsible for the biotransformation of the halogenated flame retardant tetrabromobisphenol A (TBBPA). Sediments were obtained from contaminated and uncontaminated salt marsh field sites in New Jersey. Anaerobic methanogenic sediment microcosms were established and incubated for up to 130 days. TBBPA was reductively dehalogenated resulting in the transient formation of two intermediates, identified as tribromobisphenol A and dibromobisphenol A, and the formation and accumulation of bisphenol A (BPA) as the end product. Spartina sediments from both sites were found to dehalogenate TBBPA more rapidly than the Phragmites or unvegetated sediments, resulting in greater production of BPA. Microbial community diversity as measured by in situ sediment phospholipid fatty acid (PLFA) composition prior to TBBPA exposure, was found to be higher in the uncontaminated sediments; differences in microbial PLFA diversity were not seen in contaminated sediments associated with either the different plant species or unvegetated sediment. The results of this study demonstrate that these two plant species affected sediment microbial community function with respect to dehalogenation capabilities, even though the disturbed and undisturbed sediments varied in microbial community composition.  相似文献   

13.
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14.
滨海湿地周期性干湿交替过程对沉积物氮素转化产生深刻影响,以崇明东滩湿地为原型对象,采集现场沉积物及海水样,通过室内模拟方法研究了沉积物反硝化酶-硝酸还原酶(Nar),亚硝酸还原酶(Nir),羟胺还原酶(Hyr)活性对干湿交替过程的响应。结果表明,半月潮驱动下干湿交替过程中,沉积物从干燥(7%)状态变湿(46%49%)使Nar、Nir活性迅速增加,较高的酶活性(NO3--N 6.449%)使Nar、Nir活性迅速增加,较高的酶活性(NO3--N 6.49.6 mg 10 g-124 h-1;NO2--N 5.59.6 mg 10 g-124 h-1;NO2--N 5.57.8 mg 10 g-124 h-1)至少维持24 h以上;变干过程中,当含水量降至10%左右时,Nar活性短暂升高后逐渐降至很低水平,Nir活性呈现低但稳定的变化特征。日潮驱动下的干湿交替过程中,Nar、Nir活性分别稳定的变化在NO3--N 14.7±2.1 mg 10 g-124 h-1和NO2--N 8.7±1.8 mg 10 g-124 h-1;沉积物短暂淹水期间Hyr表现出较高活性。持续淹水过程中,Nar、Nir活性变化在NO3--N 10.37.8 mg 10 g-124 h-1)至少维持24 h以上;变干过程中,当含水量降至10%左右时,Nar活性短暂升高后逐渐降至很低水平,Nir活性呈现低但稳定的变化特征。日潮驱动下的干湿交替过程中,Nar、Nir活性分别稳定的变化在NO3--N 14.7±2.1 mg 10 g-124 h-1和NO2--N 8.7±1.8 mg 10 g-124 h-1;沉积物短暂淹水期间Hyr表现出较高活性。持续淹水过程中,Nar、Nir活性变化在NO3--N 10.313.9 mg 10 g-124 h-1和NO2--N6.613.9 mg 10 g-124 h-1和NO2--N6.69.6 mg 10 g-124 h-1;Hyr活性随淹水时间的持续有所增加但变异性较高。滨海湿地中、低潮滩带沉积物Nar、Nir活性相似并明显高于高潮滩带沉积物的酶活性,变干过程两种酶的活性低于较高含水量时沉积物的酶活性。  相似文献   

15.
对外来种互花米草替代本土植物盐蒿后生长8、12、14年的湿地土壤以及盐蒿湿地表层土壤(0～10 cm)的活性有机碳(微生物量碳、可溶性有机碳)特征进行了研究,分析了不同湿地的土壤活性有机碳与土壤总有机碳之间的关系。结果表明:不同类型湿地的土壤活性有机碳组分含量存在显著差异,土壤活性有机碳、土壤总有机碳的变化趋势一致,表现为互花米草湿地>盐蒿湿地,且随着互花米草生长时间增长而明显增加;土壤活性有机碳与土壤总有机碳存在显著正相关关系;土壤活性有机碳与土壤总有机碳的比值则随着互花米草生长时间增长而逐渐减小,表明入侵年限长的互花米草湿地活性有机碳库周转率降低,生物可利用性减小,有利于土壤有机碳的累积。这可能是互花米草生长导致土壤总有机碳含量显著增加的主要原因。  相似文献   

16.

Background, aim, and scope

Bahía Blanca estuary is characterized by the occurrence of large intertidal areas, including both naked tidal flats and salt marshes densely vegetated with Spartina alterniflora. The estuary is strongly affected by human activities, including industrial and municipal discharges, harbor maintenance, cargo vessels and boat navigation, oil storage and processing, etc. Even numerous studies have reported the occurrence and distribution of heavy metals in sediments and biota from this estuary, although the function of the halophyte vegetation on metals distribution was at present not studied. The main objective of the present study was to understand the potential role of the salt marshes as a sink or source of metals to the estuary, considering both the obtained data on metal levels within sediments and plants from the studied areas at naked tidal as well as vegetated flats.

Materials and methods

The selected study area, named Villa del Mar, was located in the middle estuary coast. The sampling was carried out under low tide conditions, and the sampling area was divided into two parts: A (close to Villa del Mar) and B (north-westerly of Villa del Mar). In each part, two integrated samples of S. alterniflora (the first in the medium-salt marsh and the second in the higher one) were collected. Also sediments associated with the roots of S. alterniflora were taken at the same locations, in addition to another sediment sample from the naked zones of the tidal flats (without any vegetation). After corresponding treatment at the laboratory, plant and sediment samples were mineralized according to Marcovecchio and Ferrer, J Coast Res 21:826–834, 2005), in order to measure their metal concentrations by atomic absorption spectroscopy (AAS). Analytical quality (AQ) was checked against certified reference materials from NIES, Tsukuba (Japan).

Results

Most of the Spartina samples have shown highest Cd and Mn concentrations in the aerated parts of the plants, indicating an allocation process from the roots up to the leaves. Most of the samples have presented non-detectable Pb and Cr values. Cu, Fe, Ni, and Zn have presented highest concentrations in the underground parts of the plant, suggesting an accumulation process in the roots and rhizomes. In the case of sediments, samples from those sites located far away from Villa del Mar have presented greater concentrations on the sediments associated with underground parts of Spartina than those from the naked tidal flat, for almost all of the metals studied. Unlike this, the samples from the site close to Villa del Mar have shown the higher concentrations in sediments from the naked tidal flat.

Discussion

Marsh plants are known to absorb and accumulate metals from contaminated sediment, and this is one reason that allows wetlands to be used for wastewater treatment. It was observed that those sets of samples from the same salt marsh levels (e.g., A.1 and B.1, or A.3 and B.3) have shown similar heavy metal distribution trends, although even their corresponding concentrations could be different. Thus, the concentrations of Cu, Zn, Ni, and Fe in the medium-salt marshes were higher in the underground tissues (roots plus rhizomes), with the exception of Mn, which was seen to be higher in the aboveground parts. The same tendency occurs at high-salt marshes for these heavy metals, with the exception of Ni. This fact was sustained regarding the fact that the levels mentioned (medium-salt marsh and high-salt marshes) must have the same exposition to heavy metal sources, similar physical-chemical conditions regulating metal distribution within the compartments on the salt marshes or, simultaneously, both mentioned processes. Moreover, metals in this macrophyte can remain after the leaves have died and turned into detritus. The metals present in the detritus can be passed on to consumers (Quan et al., Mar Environ Res 64:21–37, 2007)). Keeping in mind that Bahía Blanca estuary’s salt marshes are inundated twice each day by tidal water for 3–4 h, macrophytes may act as a conduit for the movement of metals from the sediment to the estuarine body and near-coastal system.

Conclusions and recommendations

Considering the comments on the previous paragraphs, salt marshes from Bahía Blanca estuary are sources or sinks for metals? It can be sustained that both are the case, even if it is often stated that wetlands serve as sinks for pollutants, reducing contamination of surrounding ecosystems (Weis and Weis, Environ Int 30:685–700, 2004)). In the present study case, the sediments (which tend to be anoxic and reduced) act as sinks, while the salt marshes can become a source of metal contaminants. This is very important for this system because the macrophytes have been shown to retain the majority of metals in the underground tissues, and particularly in their associated sediments. This fact agreed well with previous reports, such as that from Leendertse et al., Environ Pollut 94:19–29, 1996) who found that about 50% of the absorbed metals were retained in salt marshes and 50% was exported. Thus, keeping in mind the large spreading of S. alterniflora salt marshes within Bahía Blanca estuary, it must be carefully considered as a re-distributor of metals within the system.  相似文献   

17.
Sediment pollution by metals is of high interest considering that it can affect marine life. The estuaries' quality may be reflected by the environmental intertidal zone condition. Subsurface sediments collected at the nude tidal flats from three sampling stations in the Bahía Blanca Estuary were analyzed for total metals concentrations (Hg, Cd, Pb, and Cr), distribution, and geochemical partitioning. Most of the elements (Hg, Cd, and Cr) have shown highest concentration values in the industrial-influenced area. Maximum value of Pb was obtained where the main freshwater input discharges. Intertidal sediments have presented higher values of Cr than the subtidal ones. Cd and Pb contents near the industrial area were strongly higher in the subtidal zones. The distribution of Cd and Pb demonstrated the occurrence of a diffusion pattern from the land toward the sea, showing a dependence on both the metal itself and/or the source. Not all studied metals have shown the highest content in the fine fraction. The chemical partitioning in the fine fractions offered evidence that the tidal flats were an important source as well as sink of metals to the adjacent coastal area. The studies of intertidal sediments provide an integrative knowledge on the potential effects of different trace metals in the environment and they must be used in the contamination studies within coastal areas.  相似文献   

18.
Oil spills may detrimentally damage sensitive coastal habitats, such as coastal wetlands. Successful restoration of oiled habitats primarily depends on the tolerance of vegetation transplants to oil. In this study, tolerance limits of the dominant coastal brackish marsh plant Spartina patens to South Louisiana crude (SLC) oil and its phytoremediation effectiveness on petroleum hydrocarbons in wetland sediments were investigated in the greenhouse environment. Spartina patens was transplanted into brackish marsh sediments contaminated with SLC oil at concentrations of 0, 40, 80, 160, 320, 640 and 800 mg SLC oil g?1 dry sediment. High oil concentrations adversely affected plant stem density, aboveground biomass and belowground biomass even one year after transplantation. At the 320 mg g?1 oil dosage, plant belowground biomass was significantly lower than the control although aboveground variables were not significantly different from the control. All plant parameters mentioned above at the 640 mg g?1 oil dosage were less than 50% of the control. Spartina patens did not survive the 800 mg g?1 oil dosage. The tolerance limit of S. patens to SLC was estimated about 320 mg oil g?1 dry sediment. In addition, S. patens transplants enhanced oil degradation in the sediment; concentrations of residual total petroleum hydrocarbons (TPH) in the sediments vegetated by S. patens were significantly lower than those of un-vegetated sediments for both the surface and subsurface sediment at the 40 and 160 mg g?1 SLC oil dosages. Decreases in the concentrations of polycyclic aromatic hydrocarbons (PAHs) further demonstrated the capacity of S. patens to phytoremediate residual oil; residual total targeted PAHs in the phytoremediation treatment were less than 20% of the un-vegetated treatment at the 40 mg g?1 oil dosage. These results demonstrated the potential of phytoremediation with S. patens to simultaneously restore and remediate petroleum-contaminated coastal marsh habitats.  相似文献   

19.
对山东东营市河口区新户乡所在的渤海海岸带和江苏连云港市徐圩盐场所在的黄海海岸带土壤质地、pH值、含盐量、有机质含量等理化性质指标以及地下水位和矿化度进行调查、测定与对比分析,并根据土壤理化性质和地下水的测定结果以及植物的耐盐性和对水湿状况适应性能,在连云港徐圩盐场的不同地段,选择不同的树种进行造林实验。结果表明,山东东营地区选择的冬枣树种对该地的气候、土壤、地下水比较适应,造林取得了良好经济效益和生态效益;连云港徐圩盐场各地段所选择的冬枣、紫穗槐、杨树、苦楝、栾树、青檀、杜仲、国槐、刺槐、旱柳、合欢、银杏等树种对当地局地环境也较为适应,总体造林效果基本达到设计要求,但在局部地段的苗木选择、植树方法等方面值得进一步探讨。  相似文献   

20.
Objective  Microbial communities are a central component of trophic dynamics and biogeochemical processes on coastal systems, since most of the processes in sediments are mediated by microorganisms and carried out by enzymes. Microorganisms play a key role in decomposition processes in salt marsh sediments, although the significance of microbial dynamics is largely unexplored. A culture-dependent (Ecoplate) and a culture-independent (extracellular enzyme activity [EEA]) approaches were evaluated in their ability to distinguish the catabolic potential among sediments from Tagus estuary salt marshes with different proximities to anthropogenic sources. Methods  Ecoplate was used to analyse the salt marsh community-level physiological profiles (CLPPs). Results were expressed as the net area under the curve for each of the 31 response wells over a 3-day incubation period in two sediment horizons. The catabolic profiles for salt marsh samples were analysed by Principal Component Analysis (PCA) and hierarchic clustering methods. EEA was analysed by fluorescein diacetate (FDA) hydrolysis in two sediment horizons. The FDA is catalysed by extracellular enzymes, i.e. esterases, lipases and partially by proteases. Results were expressed as μg g−1d wt h−1. Results and Discussion  In this study the CLPP and EEA data were not generally correlated. In Corroios salt marsh only in surface sediments higher net areas corresponded to higher extracellular enzymatic activity, and in Alcochete deep sediments lower net areas corresponded to lower enzymatic activity. Although EEA profiles more directly reflect the inherent activity of resident community in each salt marsh sample, the CLPP profiles provide better assessments of diversity. ESS-Submission Editor: Prof. Dr. Peter Schroeder, Institute of Soil Ecology, Department of Rhizosphere Biology, GSF — National Research Center for Environment & Health, Ingolstaedter Landstrasse 1, 85758 Neuherberg, Germany (peter.schroeder@gsf.de)  相似文献   

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