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1.
A factorial experiment based on a completely randomized design with three replicates was conducted to evaluate effects of sixteen different mixtures of organic nitrogen sources and antibiotics which were supplemented to an Murashige and Skoog (MS) medium containing 4 mg L?1 2,4-Dichlorophenoxyacetic acid (2,4-D), 0.4 mg L?1 benzyl-aminopurine (BAP), 30 g L?1 sucrose, 8 g L?1 Agar-agar on fresh weight and dry weight (assessed after three days of drying at 70°C) of calli and in vitro callogenesis from scutellum of four indigenous Iranian Indica rice (Oryza sativa L.) cultivars, including ‘Hashemi’, ‘Gerdeh’, ‘Hasani’, and ‘Gharib’. It was found that proline at 2.8 g L?1 is the most effective source of organic nitrogen in enhancing growth, whereas asparagine at 0.75 g L?1 inhibited the calli growth. Hygromycin at 50 mg L?1, with slight differences between the cultivars, could effectively stunt the growth of untransformed calli. Mixture of cefotaxime (250 mg L?1) and vancomycin (250 mg L?1) did not have any significant effects on calli growth, although this treatment was slightly phytotoxic.  相似文献   

2.
In this study, interactions of nickel sulfate and urea sprays on vegetative growth, yield and leaf mineral contents in strawberry were investigated. Rooted Pajaro strawberry plants were potted in 3 liter pots filled with soil, leaf mold and sand (1:1:1, v/v/v). Established plants were foliar sprayed with nickel sulfate at 0, 150, 300 and 450 mg L?1 and urea 0 and 2 g L?1 concentrations. Results indicated that nickel (Ni; 300 mg L?1) plus urea (2 g L?1) significantly increased the yield and runner numbers. Nickel sulfate at the rate of 300 and 150 mg L?1and urea (2 g L?1) significantly increased the crown numbers. The greatest root fresh and dry weights were obtained from untreated plants. Urea at 2 g L?1 without nickel significantly increased shoot fresh and dry weights. Nickel at 450 mg L?1 without urea significantly increased Ni concentration in leaves. Overall, nickel sulfate at 150 and 300 mg L?1 along with urea at 2 g L?1 were the best treatments.  相似文献   

3.
This study describes seed germination and micropropagation of Senegalia nigrescens, an economic, medicinal and nitrogen-fixing species of South Africa. Seeds of S. nigrescens were subjected to pre-sowing treatments including soaking in cold water for 24?h, sulphuric acid (H2SO4) or hydrochloric acid (HCl) for 4, 8 and 12?min and mechanically scarifying seeds before sowing on Petri plates with wet filter paper. Mechanically-scarified seeds were also sown aseptically on a filter paper bridge, plain agar, ½ or full strength Murashige and Skoog (MS) basal medium. Single nodal explants from MS-derived seedlings were grown on MS media supplemented with 0.0, 0.5, 1.0 and 2.0 mg?L?1 of benzylaminopurine (BAP) or kinetin (KIN) and a combination of 0.5 mg?L?1 of BAP and KIN to investigate shoot multiplication. No significant differences were observed in the number of shoots produced across all treatments. However, the treatment containing 1.0 mg?L?1 KIN produced a significantly higher shoot length (14.17?±?5.20 mm) than 0.5, 1.0 and 2.0 mg?L?1 BAP (7.67?±?3.87, 6.75?±?2.93 and 8.70?±?3.56 mm, respectively). The highest rooting rate (16.7%) was obtained on ¼ strength MS supplemented with either indole-3-acetic acid (IAA) or indole-3-butyric acid (IBA) at concentrations 1.0 and 0.5 mg?L?1, respectively. Rooted plantlets were successfully acclimatised with a 66.7% survival rate. The findings from this study would be of great benefit for the commercial propagation of S. nigrescens.  相似文献   

4.
Terminal drought stress (drought at reproductive growth stage) has been considered a severe environmental threat under changing climatic scenarios and undoubtedly inhibits sunflower production. A field study was conducted to explore the potential role of foliar applied boron (B) (0, 15, 30, 45 mg L?1) at late growth periods of sunflower in alleviating the adversities of terminal drought stress (75, 64, 53 mm DI) grown from inflorescence emergence to maturity stages. The plant water relations such as leaf relative water content (RWC), water potential (Ψw), osmotic potential (Ψs), and turgor pressure (Ψp) were increased significantly with B foliar sprays while exposed to terminal drought stress. Foliar B application considerably improved the nitrogen and B concentrations in leaf and seed tissues, and also chlorophyll a and b pigments under terminal drought stress conditions. Drought-induced proline accumulation prevented the damages caused by drought stress, nevertheless, B foliar spray increased its contents. Compared to well-watered conditions, terminal drought stress substantially declined the growth performance in terms of reduced leaf area index (LAI), crop growth rate (CGR), net assimilation rate (NAR), and total dry matter (TDM) production; however, foliar B supply (30 mg L?1) might be helpful for improving drought tolerance in sunflower with reduced growth losses.  相似文献   

5.
Abstract

To evaluate the hypothesis that plant-mediated oxygen supplies decrease methane (CH4) production and total global warming potential (GWP) in a tropical peatland, the authors compared the fluxes and dissolved concentrations of greenhouse gases [GHGs; CH4, carbon dioxide (CO2) and nitrous oxide (N2O)] and dissolved oxygen (DO) at multiple peatland ecosystems in Central Kalimantan, Indonesia. Study ecosystems included tropical peat swamp forest and degraded peatland areas that were burned and/or drained during the rainy season. CH4 fluxes were significantly influenced by land use and drainage, which were highest in the flooded burnt sites (5.75 ± 6.66 mg C m?2 h?1) followed by the flooded forest sites (1.37 ± 2.03 mg C m?2 h?1), the drained burnt site (0.220 ± 0.143 mg C m?2 h?1), and the drained forest site (0.0084 ± 0.0321 mg C m?2 h?1). Dissolved CH4 concentrations were also significantly affected by land use and drainage, which were highest in the flooded burnt sites (124 ± 84 μmol L?1) followed by the drained burnt site (45.2 ± 29.8 μmol L?1), the flooded forest sites (1.15 ± 1.38 μmol L?1) and the drained forest site (0.860 ± 0.819 μmol L?1). DO concentrations were influenced by land use only, which were significantly higher in the forest sites (6.9 ± 5.6 μmol L?1) compared to the burnt sites (4.0 ± 2.9 μmol L?1). These results suggest that CH4 produced in the peat might be oxidized by plant-mediated oxygen supply in the forest sites. CO2 fluxes were significantly higher in the drained forest site (340 ± 250 mg C m?2 h?1 with a water table level of ?20 to ?60 cm) than in the drained burnt site (108 ± 115 mg C m?2 h?1 with a water table level of ?15 to +10 cm). Dissolved CO2 concentrations were 0.6–3.5 mmol L?1, also highest in the drained forest site. These results suggested enhanced CO2 emission by aerobic peat decomposition and plant respiration in the drained forest site. N2O fluxes ranged from ?2.4 to ?8.7 μg N m?2 h?1 in the flooded sites and from 3.4 to 8.1 μg N m?2 h?1 in the drained sites. The negative N2O fluxes might be caused by N2O consumption by denitrification under flooded conditions. Dissolved N2O concentrations were 0.005–0.22 μmol L?1 but occurred at < 0.01 μmol L?1 in most cases. GWP was mainly determined by CO2 flux, with the highest levels in the drained forest site. Despite having almost the same CO2 flux, GWP in the flooded burnt sites was 20% higher than that in the flooded forest sites due to the large CH4 emission (not significant). N2O fluxes made little contribution to GWP.  相似文献   

6.
Abstract

Laboratory experiments were conducted to determine the influence of three types of decomposing fresh organic materials [pig manure (PM), Astagalus sinicus (AS), and Alternanthera philoxeroides (AP)] on dissolution of Fe2O3 and ZnO and also the use of a loamy calcareous soil as an alternative source of iron (Fe) and zinc (Zn). Levels of Fe and Zn concentrations in composting solutions changed with composting time. The maximum levels of solution Fe resulting from the decomposition of the three organic materials were 20, 612, and 348 mg L?1 for PM, AS, and AP, respectively, when the soil was supplied as the Fe source, and 17, 32, and 16 mg L?1 when Fe2O3 was supplied as the Fe source. Corresponding maximum levels of solution Zn were 0.9, 0.7, and 1.3 mg L?1 and 35, 171, and 103 mg L?1 when the soil and ZnO was supplied as the Zn source respectively for the same three organic materials.  相似文献   

7.
Silicon (Si) is the second most abundant element in the soil and can alleviate several abiotic stresses in many plant species. However, the mechanisms involved in alleviating ferrous iron (Fe2+) toxicity by Si are still largely unknown, and no study has investigated the role of Si on the Fe2+‐induced oxidative stress and antioxidant system in rice. Four cultivars of Asian and African rice (Oryza sativa L. and Oryza glaberrima Steud) were grown for 4 weeks under hydroponic conditions with or without Fe2+ (250 mg Fe2+ L?1) and with or without Si (250 mg SiO2 L?1). The plants that were treated with Fe2+ suffered Fe2+ toxicity, and Si helped to alleviate the toxicity symptoms. The bronzing index and the Fe concentration in the foliar tissue increased in the presence of Fe2+ but decreased significantly with the application of 250 mg SiO2 L?1. The concentration of malonyldialdehyde, that is commonly used as an indicator of oxidative stress, increased in the foliar tissue in the presence of 250 mg Fe2+ L?1 in the nutrient solution. The application of 250 mg SiO2 L?1 in the plant nutrient solution treated with Fe2+ considerably limited the increase of malonyldialdehyde. However, no significant effect of Si application on the activities of antioxidant enzymes (catalase and ascorbate peroxidase) and non‐enzymatic antioxidants (total ascorbate, reduced ascorbate, oxidized ascorbate, and the ratio of the reduced to oxidized forms) was observed in the rice plants that were grown in the presence of Fe2+. These results suggest that Si does not act directly on the antioxidant defense system of rice but reduces the plant Fe2+ concentration, which reduces the oxidative stress.  相似文献   

8.
Abstract

To assess soil-to-plant transfer of various elements more precisely, the concentrations of the elements extracted from soil samples using eight chemical solutions were compared with the results of a pot cultivation experiment of komatsuna (Brassica rapa L. var. perviridis) or buckwheat (Fagopyrum esculentum M.) using the soils. From agricultural fields in Aomori, Japan, 16 soil samples were collected. Elements in the samples were extracted using acids (1 mol L?1 HNO3, 0.1 mol L?1 HNO3, 0.01 mol L?1 HNO3), chelating agents (0.05 mol L?1 EDTA), neutral salt solutions (1 mol L?1 NH4OAc, 1 mol L?1 NH4NO3, 0.01 mol L?1 CaCl2) and pure water. The 28 elements in the extracted solutions and plant samples were determined. The extractability of many metals was higher in 1 mol L?1 HNO3, 0.1 mol L?1 HNO3 and the 0.05 mol L?1 EDTA solutions than in the other extractants. Higher extractability using the NH4OAc solution than the NH4NO3 solution was observed for some elements, in particular U. Extractability by pure water was not always lowest among these methods, probably because of dispersion of colloidal substances in the extracted solution. The pot cultivation experiment showed that the concentrations in soil and in the extracted fraction using 1 mol L?1 HNO3, 0.1 mol L?1 HNO3 or the EDTA solution did not correlate with the concentration in plant samples for most elements. Plant uptake of Zn, Y and La by komatsuna correlated well with their concentrations in extracts with neutral salt solutions or 0.01 mol L?1 HNO3. Concentrations of Al, Cu and Cd in buckwheat were also correlated with the concentrations in the extracts.  相似文献   

9.
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10.
Microbial decomposition of extracted and leached dissolved organic carbon (DOC) and nitrogen (DON) was demonstrated from three pasture soils in laboratory incubation studies. DOC concentration in water extracts ranged between 29 and 148 mg C L?1 and DON concentration ranged between 2 and 63 mg N L?1. Between 17 and 61 % of the DOC in the water extracts were respired as CO2 by microbes by day 36. DON concentrations in the extracts declined more rapidly than DOC. Within the first 21 days of incubation, the concentration of DON was near zero without any significant change in the concentration of NO3 ? or NH4 +, indicating that microbes had utilized the organic pool of N preferentially. Decomposition of leached DOC (ranged between 7 and 66 mg C L?1) and DON (ranged between 6 and 11 mg N L?1) collected from large lysimeters (with perennial pasture; 50 cm diameter?×?80 cm deep) followed a similar pattern to that observed with soil extracts. Approximately 28 to 61 % of the DOC in leachates were respired as CO2 by day 49. The concentration of DON in the leachates declined to below 1 mg N L?1 within 7–14 days of the incubation, consistent with the observations made with extractable DON. Our results clearly show that DOC and DON components of the dissolved organic matter in pasture soils, whether extracted or leached, are highly decomposable and bioavailable and will influence local ecosystem functions and nutrient balances in grazed pasture systems and receiving water bodies.  相似文献   

11.
Influence of drought and salt stress on different morphological and physiological growth parameters in Capsicum annuum inoculated with our isolates was estimated during the present study. Bulkhorderia cepacia was reported to possess the maximal, whereas Citrobacter feurendii the least plant growth promoting efficacy under salt and drought stress. ACC Deaminase activity of purified B. cepacia, C. feurendii and Serratia marcescens was 12.8 ± 0.44, 12.3 ± 0.56 and 11.7 ± 0.53 μM αKB mg?1 min?1 respectively. Under drought stress, B. cepacia showed maximum tolerance as it produced 4.893 ± 0.06 mg/mg protein of exopolysaccharide followed by C. feurendii and S. marcescens that produced 4.23 ± 0.03 and 3.46 ± 0.05 mg/mg protein, respectively. Chlorophyll “a” concentration was recorded 5.7 gm L?1 in B. cepacia inoculated plant (without stress) and was sustained till 2.9 gm L?1 even under the highest tested drought period. Chlorophyll “a” concentration in the B. cepacia inoculated plant under the highest tested NaCl concentration was 3.2 gm L?1. Thus, bacterial inoculation mitigates the effects of salinity by the proliferation of root system, increasing plant biomass proving to be potential bioinoculum for alleviating abiotic stress.  相似文献   

12.
The effect of increasing chloride content in nutrient solution on nutrient composition in root environment, interaction of nutrients in leaves and yield of greenhouse tomato cv. ‘Grace F1’ grown in rockwool were searched. In Experiment I (2004–2005) the levels of 15, 30, 60, and 90 mg Cl·L?1 but in Experiment II (2006) 30, 60, 90 and 120 mg Cl·L?1 of nutrient solution were tested. The sources of chloride were water (9.6–10.7 mg Cl·L?1) and calcium chloride (CaCl2·2H2O) but the rest of nutrients and sodium in all treatments were on the same levels. It was found that increasing content of chloride from 15 to 60 mg Cl·L?1 enhanced the total and marketable fruit yield. Within the range of 60 to 90 mg Cl·L?1 the yield was on the optimum level but the content of 120 mg Cl·L?1 declined it. Increasing chloride content in the nutrient solutions was reflected in rising of chlorine content in leaves. The concentration of chloride above 60 mg C·L?1 reduced the content of nitrogen but above 90 mg C·L?1 declined the content of calcium, sulfur and zinc in leaves. The antagonism between Cl:N, Cl:Ca: Cl:S and Cl:Zn was appeared. More variable interaction were between Cl:K and Cl:B. At the low levels of chloride, from 15 to 60 mg Cl·L?1, potassium and boron content were decreased but at the higher ones, from 90 to 120 mg·L?1, these nutrients had increasing course. It was not found out the effect of chloride contents on macro and microelement contents in nutrient solution emitted from drippers however their content upraising in root medium (rockwool). The highest increase was found out for Na 95.1 and 64.9 % (Exp. I and II - respectively), next for Ca (76.0, 70.1 %), Cu (62.5 and 71.0 %), Cl (43.6, 24.4), B (33.3, 21.0 %), N-NO3 (30.4, 49.6 %), Zn (29.5, 32.8 %), S-SO4 (25.9, 25.5 %), K (24.5, 24.1 %), Fe (19.8, 19.2 %), Mn (17.5, 21.3 %) and Mg (14.9, 11.7). Advantageous effect of chloride on tomato yield justified the need to introduce for the practice adequate chlorine nutrition, and recommend to maintain 60 to 90 mg Cl·L?1 in nutrient solution. The best yield appeared when content of chlorine in leaves (8th or 9th leaf from the top) was in the range 0.48-0.60 % of Cl in d. m.  相似文献   

13.
《Journal of plant nutrition》2013,36(6):1041-1048
Abstract

Pollution of water and soil by heavy-metal byproducts of mining and industrial operations is an environmental problem in many parts of Taiwan. Bermudagrass (Cynodon dactylon) and seashore paspalum (Paspalum vaginatum Swartz) are two of the most saline-tolerant warm-season turfgrasses. A whole-plant microculture (WPMC) system has been developed that permits intact-root growth observation through a gelrite-solidified culture medium. To screen efficiently for potential whole-plant-level salt tolerance in these turfgrasses, root morphology was studied using scanning electron microscopy. Nodal explants at the same developmental stage as the plants were sterilized, and each explant was placed in a Pyrex test tube containing 25 mL of 1/2 Murashige and Skoog (MS) media with 30 g L? 1 sucrose, 1 mg L? 1 IBA, 0.1 mg 2ip, 2.5 g L? 1gelrite, and either 0, 1, or 100 ppm of CdCl2 stress media for five months. The experimental results demonstrated significant differences among stress media in terms of root number, root length, shoot length, nodal number, and ratio of root length to shoot length of plants. Moreover, scanning electron microscopy (SEM) examination of regenerated WPMC roots under cadmium (Cd)-free, 1, and 100 ppm of CdCl2 stress media revealed obvious morphological and adaptational differences. In this investigation, microculture at the whole-plant level in vitro enables intact root growth observations through the culture medium and vessel, and offers a potential pre-screening method for putative heavy-metal-tolerant turfgrasses before commercialization and use in phytoremediation to clean up contaminated soils.  相似文献   

14.
Four okra cultivars [Abelmoschus esculentus (L.) Moench] were cultivated for two growing periods at nitrogen (N) application rates of 150, 300 and 450 mg N L?1. There was no effect of N on pod size (length and diameter) or on the number of seeds per pod and seed size (mean 1000 seed weight), all these characteristics of which related to the genotype. High N application (450 mg N L?1), increased the seed yield of the cultivar with the lowest flower induction (Boyiatiou), but only in experiment 2. In Veloudo, seed yield was highest at 300 mg N L?1, whereas in Pylaias and Clemson 450 mg N L?1 reduced seed yield. In all cultivars, seeds produced at an N rate of 450 mg N L?1 exhibited a significantly higher percent germination N, possibly by reducing the incidence of seed hardness.  相似文献   

15.
The boron (B) sufficiency range for plant growth is narrow and its management is problematic under brackish irrigation water. This study was conducted to evaluate the B requirement of mungbean at different sodium adsorption ratios of irrigation waters (SARiw) [control, 8 and 16 (mmolc L?1)1/2]. The boron adsorption characteristics of a loamy soil were first determined in the laboratory by equilibrating 2.5 g soil with 0.01 M CaCl2 solution containing different B levels. Boron rates for a pot study were computed against different soil solution levels by fitting sorption data in a modified Freundlich model [x/m = K f (EBC)1/n ]. The maximum increase in shoot dry matter was 11.9% when B was applied at 1.29 mg kg?1 soil at control SARiw. Visual leaf B toxicity symptoms appeared at higher B rates and became severe at higher SARiw. By contrast to Ca, shoot concentrations of B and Na increased significantly with B application and SARiw. For optimum shoot growth, internal and external B requirements were 25 mg B kg?1 shoot dry matter and 0.39 mg B L?1 soil solution, respectively, at control SARiw. At higher SARiw, a lower concentration of B in plant shoots and soil solution had an inhibitory effect on plant growth.  相似文献   

16.
Comamonas sp. UVS was able to decolorize Reactive Blue HERD (RBHERD) dye (50 mg L?1) within 6 h under static condition. The maximum dye concentration degraded was 1,200 mg L?1 within 210 h. A numerical simulation with the model gives an optimal value of 35.71?±?0.696 mg dye g?1 cell h?1 for maximum rate (Vmax) and 112.35?±?0.34 mg L?1 for the Michaelis constant (Km). Comamonas sp. UVS has capability of decolorization of RBHERD in the presence of Mg2+, Ca2+, Cd2+, and Zn2+, whereas decolorization was completely inhibited by Cu2+. Metal ions also affected the levels of biotransformation enzymes during decolorization of RBHERD. Comamonas sp. UVS was also able to decolorize textile effluent with significant reduction in COD. The biodegradation of RBHERD dye was monitored by UV–vis spectroscopy, FTIR spectroscopy, and HPLC.  相似文献   

17.
Abstract

Nitrite (NO2 ?‐N) toxicity symptoms have been observed on lettuce (Lactuca sativa) at various locations in California. The objective was to evaluate the symptoms of ammonium (NH4 +‐N) and nitrite (NO2 ?‐N) toxicity on Sundevil iceberg lettuce and Paragon romaine lettuce and to determine lettuce growth and biomass production under different levels of NO2 ?‐N. Hydroponic studies under greenhouse conditions were conducted using nutrient solutions containing nitrate (NO3 ?‐N) and two other forms of nitrogen (NO2 ?‐N and NH4 +‐N) applied at a constant concentration (50 mg NL?1) or using different NO2 ?‐N levels (0, 5, 10, 20, 30, and 40 mg N L?1) and a constant NO3 ?‐N level (30 mg N L?1). Crown discoloration (brownish color) was observed for lettuce grown in both NO2 ?‐N and NH4 +‐N solutions approximately 3 weeks after transplanting into the hydroponic systems. Lettuce grown in NO3 ?‐N solution produced larger biomass and greater number of leaves per plant than lettuce grown in NO2 ?‐N or NH4 +‐N solutions. Increasing the concentration of NO2 ?‐N suppressed plant height, fresh and dry biomass yield, and number of leaves and increased the root vascular discoloration. Lettuce growth was reduced more than 50% at NO2 ?‐N concentrations greater than 30 mg N L?1. Even at 5 mg NO2 ?‐N L?1, growth was reduced 14 and 24% for romaine and iceberg lettuce, respectively, relative to that obtained in nitrate solution. Although concentrations between 5 and 40 mg NO2 ?‐N L ?1 reduced dry biomass similarly for both lettuce types, toxicity symptoms were more severe in iceberg lettuce than in romaine.  相似文献   

18.
The use of vermicompost as a soil amendment is suggested as a method to reduce nitrogen (N) losses in crop production; however, it is unclear whether and how vermicompost can affect water quality after a significant irrigation or rainfall event. Bare-root strawberry plugs were grown in 1-gallon plastic pots. The treatments consisted of two media: (1) a peat:perlite soil-less mix and (2) a fine sand soil. Each media was amended with three levels of dairy manure vermicompost: 0, 10, and 25% by weight, and a biweekly synthetic fertilizer treatment of 150 mg N-P-K L?1 evaluated in a full factorial randomized block design. Drainage water from each plant was collected each week for 18 weeks and analyzed for NO3? concentration. In the first 2 weeks, high (1000–5000 mg L?1) amounts of NO3? leaching occurred in all vermicompost-amended media relative to non vermicompost-amended media, but this leaching significantly (p < 0.01) decreased over time across all vermicompost treatments. Strawberry growth response to 10% vermicompost was similar to synthetic fertilizer only treatments. Plants grown with vermicompost at 25% with synthetic fertilizer had the highest above-ground vegetative biomass (15.3 g) relative to plants with synthetic fertilizer only (5.3 g). These data suggest vermicompost addition rates of 10 and 25% by weight promote high vegetative biomass in greenhouse strawberry but may facilitate high initial nitrate leaching, which can negatively affect water quality and environmental health.  相似文献   

19.
The hydrobiological parameters of the waters in the vicinity of ash slurry and cooling water outfall from Ennore Thermal Power Station located on the shore of Bay of Bengal, Madras were determined. In the outfall site, an increase in mean temperature (35 °C), salinity (3.5%), nitrite ? N (25 μg L?1), ammonia ? N (185 μg L?1), phosphate ? P (1 mg L?1), silicate ? SiO2 (1.65 mg L?1), chlorophyll a (21.1 mg m?3), respiration (76% of gross production), suspended solids (3.84 g L?1), BOD (3.65 mg O2) and decrease in pH (8.1), dissolved oxygen (DO) (5.5 mg L?1), nitrate ? N (15 jig L?1), gross production (16.6 Mg C m?3 hr?1) were recorded. Phaeopigment and respiration were inversely related with chlorophyll a and net productivity, respectively. Microbial biomass varied spatially, but was generally low (114.5 jig L?1), at the outfall site. The hydrobiological characteristics of water with high turbidity indicate that the ash slurry and coolant water play a crucial role in a localized area resulting in environmental disturbance. The effect was profoundly influenced by an initial dilution, dispersion, wave mixing and current direction. The ecological relationships between these parameters and their implications in coastal pollution are discussed.  相似文献   

20.
The aim was to evaluate eight methods of boron (B) extraction in different soils from Córdoba and Sucre, Colombia. 37 samples were collected at a depth of 0–20 cm and carried to Soil and Water Laboratory of University of Córdoba for its chemical characterization. The available boron was extracted with the following methods: modified hot water, calcium chloride (CaCl2) 0.05, hydrochloric acid (HCl) 0.05, barium chloride (BaCl2) 0.006, manitol 0.05 + CaCl2 0.01, Ca(H2PO4)2H2O 0.008 in mol L?1, mehlich-1 and ammonium acetate (NH4OAc) (1.0 mol L?1, pH = 7.0). The major quantity of boron was extracted with mehlich-1, HCl 0.05 mol L?1 and hot water, extracting 0.36, 0.29 and 0.26 mg kg?1, respectively. The extracting solution that correlated with the hot water method was HCl 0.05 mol L?1 (r = 0.81); followed by Ca(H2PO4)2H2O 0.008 mol L?1 (r = 0.62) and mehlich-1 (r = 0.54). According to characteristic and heterogeneity of soils, we recommend HCl method to extract available boron.  相似文献   

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