蛋氨酸铜和硫酸铜在凡纳对虾饲料中的应用效果比较     

郭志勋  陈毕生  徐力文  郑石轩  湛波  刘立鹤  程开敏 《南方水产》2005,1(2):56-60

通过在饲料中分别加入不同浓度(铜元素的添加浓度分别为0、7.5、15、30、45mg·kg-1饲料)的硫酸铜和蛋氨酸铜,比较了硫酸铜和蛋氨酸铜对凡纳对虾生长、血液免疫因子及虾体铜的影响。添加蛋氨酸铜的各实验组生长速度同对照组之间没有显著差异;而添加硫酸铜的各组,只有铜添加量为30mg·kg-1饲料的试验组生长速度显著高于对照组(P<0.05),其它组同对照组之间差异不显著;成活率各组间无显著差异。除了铜添加量为15mg·kg-1饲料的试验组,各试验组对虾血清的酚氧化酶(PO)活力都高于对照组,其中当铜添加量为30mg·kg-1时最强,在此时蛋氨酸铜添加组的PO活力高于硫酸铜;随着铜添加浓度的提高,超氧化物歧化酶(SOD)活力增强,在添加量达到30mg·kg-1饲料时达到最大,此时硫酸铜组和蛋氨酸铜组间无差异,都为507。对虾肌肉中铜的含量各组间无显著差异,为(4.07±1.80)mg·kg-1,个体间差异非常大;肝胰脏中铜的最高含量为210.36mg·kg-1,最低为33.78mg·kg-1(空白对照组),明显高于肌肉中的含量。结果表明,在试验条件下,同硫酸铜相比,蛋氨酸铜没有显著的促生长效果,对肌肉、肝铜含量以及SOD活性没有显著影响。  相似文献   

Comparison of Antioxidant Activity and Antioxidant Components in Lettuce,Onion and Tomato Obtained with Different Levels and Forms of Nitrogen Fertilization     

Ragab Abdelmohsen E-Mergawi  ;Khalid Naser Al-Redhaiman  ;Hussein F. Abouziena 《农业科学与技术》2014,(7):597-604

The effect of N levels and sources on the antioxidant components in vegetable is not completely understood. Therefore, greenhouse experiments were conducted to determine the changes in antioxidant capacity diphenyl-2-picrylhydrazyl （DPPH） and ferric reducing antioxidant power （FRAP）, total phenolics, ascorbic acid, total carotene and lycopene contents in edible portions of lettuce, onion and tomato due to different nitrogen levels and sources. The experiment included three N levels （20, 40 and 60 kg/ha for lettuce trial and 60, 120 and 180 kg/ha for either onion or tomato） and four nitrogen sources （calcium nitrate, ammonium sulphate, ammonium nitrate and urea）. The antioxidant capacity and phenolic contents in lettuce was enhanced under low nitrogen level, while the antioxidant capacities, phenolics, carotenoids and lycopene in tomato fruits were not significantly affected by the nitrogen dose applied. Application of calcium nitrate caused 50% increase in DPPH and 20% in FRAP of lettuce compared to other nitrogen forms. Tomato treated with calcium nitrate or ammonium sulphate had higher phenolic and ascorbic acid contents than treated plants with ammonium nitrate or urea. Antioxidant tested parameters of onion were not significantly affected by the nitrogen treatments. Nitrogen concentration in tomato fruits significantly correlated with FRAP antioxidant capacity, phenolics, ascorbic acid, carotene and lycopene contents.  相似文献   

Effect of Biogas Digested Liquid on OH4 and N2O Flux in Paddy Ecosystem     

Ankit Singla  Kazuyuki Inubushi 《中国农业科学(英文版)》2014,(3):635-640

Biogas production generates digested slurry as a byproduct. It can be used as a fertilizer especially after its conversion into digested liquid. A pot based study was conducted in order to evaluate the effect of the application of digested liquid on CH4 and N2O flux, and plant biomass in paddy. Analysis revealed that digested liquid treated soils released more CH4 compared to ammonium sulphate and the control. Ammonium sulphate treated soil emitted the highest N20 whereas digested liquid application decreased its emission significantly. Further, the cumulative emission over 101 d of the experiment was found to be higher for CHa （16.9 to 29.9 g m^-2） compared to N20 （-49.3 to 18.9 mg m^-2） for all treatments. Digested liquid application had positive impact on plant variables such as panicle number and weight of panicles. This study suggests that digested liquid application significantly decrease N20 emission and increase CH4 emission possibly due to affecting the availability of organic C in the soil to microbial activity for methanogenesis. Another possibility for enhancing CH4 emission by following biogas digested liquid could be attributed to the increase in plant biomass.  相似文献   

Short-term competition between crop plants and soil microbes for inorganic N fertilizer     

Erich Inselsbacher  Nina Hinko-Najera Umana  Markus Gorfer  Katrin Ripka  Rebecca Hood-Novotny  Wolfgang Wanek 《Soil biology & biochemistry》2010,42(2):360-372

Agricultural systems that receive high amounts of inorganic nitrogen (N) fertilizer in the form of either ammonium (NH₄⁺), nitrate (NO₃⁻) or a combination thereof are expected to differ in soil N transformation rates and fates of NH₄⁺ and NO₃⁻. Using ¹⁵N tracer techniques this study examines how crop plants and soil microbes vary in their ability to take up and compete for fertilizer N on a short time scale (hours to days). Single plants of barley (Hordeum vulgare L. cv. Morex) were grown on two agricultural soils in microcosms which received either NH₄⁺, NO₃⁻ or NH₄NO₃. Within each fertilizer treatment traces of ¹⁵NH₄⁺ and ¹⁵NO₃⁻ were added separately. During 8 days of fertilization the fate of fertilizer ¹⁵N into plants, microbial biomass and inorganic soil N pools as well as changes in gross N transformation rates were investigated. One week after fertilization 45-80% of initially applied ¹⁵N was recovered in crop plants compared to only 1-10% in soil microbes, proving that plants were the strongest competitors for fertilizer N. In terms of N uptake soil microbes out-competed plants only during the first 4 h of N application independent of soil and fertilizer N form. Within one day microbial N uptake declined substantially, probably due to carbon limitation. In both soils, plants and soil microbes took up more NO₃⁻ than NH₄⁺ independent of initially applied N form. Surprisingly, no inhibitory effect of NH₄⁺ on the uptake and assimilation of nitrate in both, plants and microbes, was observed, probably because fast nitrification rates led to a swift depletion of the ammonium pool. Compared to plant and microbial NH₄⁺ uptake rates, gross nitrification rates were 3-75-fold higher, indicating that nitrifiers were the strongest competitors for NH₄⁺ in both soils. The rapid conversion of NH₄⁺ to NO₃⁻ and preferential use of NO₃⁻ by soil microbes suggest that in agricultural systems with high inorganic N fertilizer inputs the soil microbial community could adapt to high concentrations of NO₃⁻ and shift towards enhanced reliance on NO₃⁻ for their N supply.  相似文献   

The conformation of wheat gluten proteins. The secondary structures and thermal stabilities of α-, β-, γ- and ω-Gliadins     

Arthur S. Tatham  Peter R. Shewry 《Journal of Cereal Science》1985,3(2):103-113

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Sulphate Attack Resistance of the Concrete with Additives and Its Assessment     

YE Jian - xiong  YANG Chang - hui  ZHOU Xi  CHEN Ke 《保鲜与加工》2006,(4):118-120

The influence of three kinds of additives: silica fume,slag and fly ash on the sulphate attack resistance of concrete were studied.The experiment results show that these three kinds of additives can improve sulphate attack resistance of the concrete and the order of their efficiency from high to low is silica fume,slag and fly ash;the development of mortar expansion value is closely related to the degree of sulphate attack resistance of the concrete;integrated assessing two concrete properties: mortar expansion value and compressive strength ratio can more exactly assess the sulphate attack resistance of the concrete.  相似文献   

Influence of chloride and sulphate ions on soil enzymes   总被引：1，自引：0，他引：1  

R. Dinesh    G. Ramanathan  Harjit  Singh 《Journal of Agronomy and Crop Science》1995,175(2):129-133

Ammonium chloride (AC) and ammonium sulphate (AS) are commonly used nitrogen fertilizers. But the effect of chloride and sulphate ions from these fertilizers on soil enzyme activity has received scant attention. Hence, we conducted a pot culture study to assess the influence of chloride (as AC) and sulphate (as AS) on the activities of urease, amidase, phosphatase and dehydrogenase in soil using rice as the test crop. Chloride and sulphate levels were fixed at 132, 264 and 396 kg ha⁻¹ respectively. Controls were also performed. The enzymes were assayed at three stages of the crop growth viz., active tillering, panicle initiation and harvest.
The enzyme activities decreased with increasing chloride and sulphate levels; however, the degree of inhibition varied among the enzymes assayed and the nature and amounts of salts added. The inhibition may be due to the specific effects of chloride and sulphate ions on microbial growth and subsequent enzyme synthesis, osmotic desiccation leading to microbial cell lysis, and a salting-out effect modifying the ionic conformation of the active site of the enzyme protein.  相似文献   

曲周试区玉米秸秆不同还田方式对土壤氮素影响的探讨   总被引：4，自引：3，他引：4       下载免费PDF全文

马永良  宇振荣  江永红  罗维  田淑敏 《土壤》2003,35(1):62-65

在中国农业大学曲周试验站的潮土上进行2种不同模式的玉米秸秆还田试验,为期1年。结果发现玉米秸秆还田后前期由于能减少可溶性N的淋失,后期又释放出N,从而提高了N的利用率。土壤NO3--N含量随作物生长季节变化明显,而NH4 -N具有稳定性;土壤微生物N变化同秸秆分解状况相一致。多数时间内整翻处理的微生物N高于粉碎处理。  相似文献   

人类活动对珠江三角洲酸性硫酸盐土壤发育的影响     

LIN Chu-Xia 《土壤圈》1996,6(1):1-10

In the Pearl River Delta with more than 1000 years of intensive land reclamation history,the development of acid sulphate soils has been generally limited in terms of their acid potential (pyrite content)and spatial extent.This is attributed to the rapid delta progradation,partially resulted from increasing sediment yield caused by deforestation within the catchment and the empolderment in the estuarine embayment.The empolderment practice accompanied by the clearance of mangroves stopped the upward growth of the pyritic layer on the one hand and limited the vertical accretion of non-pyritic freshwater sediments over the pyritic layer on the one hand and limited the vertical accretion of non-pyritic freshwater sediments over the pyritic estuarine sediments on the other.In such a case,the pyritic layer in the area is frequently thin and of shallow occurrence.Under forced leaching-recharge conditions for the paddy rice cultivation ,the leaching of acid sulphate materials prevails over its production and this leads to a net loss in pyrite oxidation products.Land excavation for fishpond farming accelerates pyrite oxidation due to the direct exposure of the pyrtic sediments to air on the pond bunds.Severe acidification can intensity the environmental degradation of estuarine ecosystems.  相似文献   

Pathways and dynamics of NO₃ and NH₄ applied in a mountain Picea abies forest and in a nearby meadow in central Switzerland     

Isabelle Providoli  Rolf Siegwolf  Patrick Schleppi 《Soil biology & biochemistry》2006,38(7):1645-1657

To evaluate the pathways and dynamics of inorganic nitrogen (N) deposition in previously N-limited ecosystems, field additions of ¹⁵N tracers were conducted in two mountain ecosystems, a forest dominated by Norway spruce (Picea abies) and a nearby meadow, at the Alptal research site in central Switzerland. This site is moderately impacted by N from agricultural and combustion sources, with a bulk atmospheric deposition of 12 kg N ha⁻¹ y⁻¹ equally divided between NH₄⁺ and NO₃⁻. Pulses of ¹⁵NH₄⁺ and ¹⁵NO₃⁻ were applied separately as tracers on plots of 2.25 m². Several ecosystem pools were sampled at short to longer-term intervals (from a few hours to 1 year), above and belowground biomass (excluding trees), litter layer, soil LF horizon (approx. 5-0 cm), A horizon (approx. 0-5 cm) and gleyic B horizon (5-20 cm). Furthermore, extractable inorganic N, and microbial N pools were analysed in the LF and A horizons. Tracer recovery patterns were quite similar in both ecosystems, with most of the tracer retained in the soil pool. At the short-term (up to 1 week), up to 16% of both tracers remained extractable or entered the microbial biomass. However, up to 30% of the added ¹⁵NO₃⁻ was immobilised just after 1 h, and probably chemically bound to soil organic matter. 16% of the NH₄⁺ tracer was also immobilised within hours, but it is not clear how much was bound to soil organic matter or fixed between layers of illite-type clay. While the extractable and microbial pools lost ¹⁵N over time, a long-term increase in ¹⁵N was measured in the roots. Otherwise, differences in recovery a few hours after labelling and 1 year later were surprisingly small. Overall, more NO₃⁻ tracer than NH₄⁺ tracer was recovered in the soil. This was due to a strong aboveground uptake of the deposited NH₄⁺ by the ground vegetation, especially by mosses.  相似文献