基于^(15)N稳定同位素示踪技术的植物组合湿地对氨氮去除途径研究

人工湿地是生态修复受污染水体的重要手段,对氮的去除效果显著,但不同植物湿地对氮去除效果差异明显,因此不同类型植物组合后的湿地对氮去除效果及去除途径值得进一步研究。通过室内控制试验,以常见浮水植物绿狐尾藻(Myriophyllum elatinoides)和挺水植物梭鱼草(Pontederia cordata)为研究对象,利用^(15)N稳定同位素示踪技术探究绿狐尾藻、梭鱼草及绿狐尾藻+梭鱼草植物组合对氨氮(NH_(4)^(+)-N)的去除途径。结果表明,绿狐尾藻+梭鱼草植物组合处理相较于单一绿狐尾藻和梭鱼草处理对氮的脱除量分别提高1.8%和3.6%。基于^(15)N质量平衡,绿狐尾藻、梭鱼草和绿狐尾藻+梭鱼草植物组合处理氮去除途径的底泥吸附贡献分别为8.30%、7.96%和6.94%,植物吸收贡献分别为41.76%、35.34%和48.67%,微生物作用去除贡献分别为49.94%、56.71%和44.39%。微生物作用在湿地脱氮过程中占主导地位。相较于单一植物湿地,植物组合湿地对氮的去除效果得到提升,同时促进了植物对水体NH 4+-N的吸收。该研究有助于更好地理解植物组合湿地对氨氮的脱除途径。

二氧化碳倍增对植物叶片^(15)N自然丰度的影响

大气CO_(2)浓度上升通常会提高植物生产力并伴随叶片氮含量的下降。然而大气CO_(2)如何影响叶片^(15)N丰度及其相关机理还不清楚。以小麦和向日葵为实验材料,测定了两个CO_(2)浓度(410与820μmol•mol^(-1))处理下叶片的氮同位比值(δ^(15)N)和氮含量。结果表明:小麦和向日葵叶片氮含量随CO_(2)浓度升高呈下降趋势,然而δ^(15)N对CO_(2)浓度倍增的响应存在差异。在高CO_(2)浓度处理下小麦叶片δ^(15)N显著下降6.5‰,而向日葵叶片δ^(15)N小幅上升2.1‰,且叶片和地上部生物量显著增加。基于此,小麦的氮营养特征符合氮同化受限假说,而向日葵符合稀释效应假说。小麦叶片δ^(15)N随叶龄或者细胞年龄的增加而显著下降,因此在利用^(15)N来研究植物氮代谢时需要区分叶龄的影响。整合分析结果表明,CO_(2)浓度升高导致非豆科C_(3)植物的δ^(15)N显著下降达0.3‰,与小麦的研究结果相符。综上所述,限制硝态氮同化是CO_(2)影响植物氮代谢和^(15)N丰度的重要机制。

Characterization of Nitrogen Uptake Pattern in Malaysian Rice MR219 at Different Growth Stages Using ^(15)N Isotope

Nitrogen （N） use efficiency is usually less than 50%, and it remains a major problem in rice cultivation. Controlled release fertilizer （CRF） technology is one of the well-known efforts to overcome this problem. The efficiency of CRF, however, is very much dependent on the timing of nutrient release. This study was conducted to determine the precise time of N uptake by rice as a guideline to develop efficient CRF. Fertilizer N uptake by rice at different growth stages was investigated by using 15N isotopic technique. Rice was planted in pots, with 15N urea as N source at the rate of 120 kg/hm2. Potassium and phosphorus were applied at the same rate of 50 kg/hm2. Standard agronomic practices were employed throughout the growing periods. Rice plants were harvested every two weeks until maturation at the 14th week and analyzed for total N and 15N content. Nitrogen derived from fertilizer was calculated. Total N uptake in plants consistently increased until the 11th week. After that, it started to plateau and finally declined. Moreover, N utilization by rice plants peaked at 50%, which occurred during the 11th week after transplanting. N derived from fertilizer in rice plants were in the range of 18.7% to 40.0% in all plant tissues. The remaining N was derived from soil. Based on this study, N release from CRF should complete by the 11th week after planting to ensure the maximum fertilizer N uptake by rice plants. Efficient CRF should contribute to higher N derived from fertilizer which also resulted in a higher total N uptake by rice plants, increasing the potential of rice to produce higher yield while at the same time of reducina loss.

Determination of trophic levels of marine fish in the Yellow Sea and northern East China Sea using nitrogen stable isotope (δ^(15)N) analysis of otoliths

Fish otolithδ^(15) N(δ^(15) N_(oto))is a demonstrated source of information of dietary history for marine fi sh as it is available iN_(oto)lith archives and sedimentary deposits unlike white muscle tissue(WMT).WMT and stomach content data are insufficient for trophic level(TL)data of past fi shes which is important for the changes of marine fi shery resources over long time scales.To determine the correlation betweenδ^(15) N_(oto) and fi sh WMTδ^(15) N(δ^(15) N_(wmt))and the feasibility of usingδ^(15) N_(oto) in characterizing the TLs of marine fi shes,we conducted nitrogen stable isotope analysis(SIA)in the otolith and WMT of 36 marine fi sh species sampled from the Yellow Sea and northern East China Sea in 2011-2014.Bothδ^(15) N_(oto) andδ^(15) N_(wmt) were analyzed using an elemental analyzer coupled with an isotope ratio mass spectrometer(EA-IRMS).Multiple otoliths were combined to make each otolith measurement and were analyzed as-is without a carbonate dissolution pre-processing step.δ^(15) N_(oto) andδ^(15) N_(wmt) comparisons for species in the Yellow Sea and northern East China Sea are currently lacking and would be helpful for both regional studies and for increasing the number of species for whichδ^(15) N_(oto) andδ^(15) N_(wmt) have been compared.Additionally,to determine the relative accuracy of trophic level calculated usingδ^(15) N_(oto),we compared TL calculated fromδ^(15) N_(oto) to traditional trophic level metrics calculated usingδ^(15) N_(wmt).The results showed a positive and highly signifi cant correlation(R=0.780,P<0.001)betweenδ^(15) N_(oto) andδ^(15) N_(wmt).Trophic level estimation using WMT(TL wmt)and otolith(TL oto)showed congruence in our study,which is not entirely surprising given thatδ^(15) N_(oto) was regressed againstδ^(15) N_(wmt) and the resulting regression coefficient was used to convertδ^(15) N_(oto) toδ^(15) N_(wmt) prior to calculating TL oto.This conversion was required in order to be consistent with previousδ^(15) N_(wmt)-based calculations of TL for comparison.TL oto calculations resulted in TL values that were largely within 5%-10%of TL values calculated withδ^(15) N_(wmt).Our fi ndings show thatδ^(15) N_(oto) is a feasible technique for characterizing the TLs of marine fi sh and can also assist in food web and marine ecosystem studies.

Application of ^15N Stable Isotope Labeling Technology in Sugarcane Nitrogen Research

Nitrogen is one of the essential nutrient elements for plant growth,which plays an important role in the growth and development of sugarcane. The whole growth cycle of sugarcane needs a large amount of nitrogen. Increasing the application of nitrogen can improve the yield of sugarcane,but it will also cause environmental pollution. Therefore,how to control or reduce the application of nitrogen fertilizer while continuously increasing sugarcane yield,reduce the increase of sugarcane production cost and environmental pollution caused by excessive application of nitrogen fertilizer has become an important scientific problem faced by sugarcane industry in China.^15N stable isotope labeling technology has been applied to many crops as a nitrogen research tool. In order to better understand the demand of nitrogen fertilizer in soil-cane system,this paper reviewed nitrogen allocation in plants,nitrogen loss,nitrogen recycling and endogenous nitrogen fixation of sugarcane based on^15N stable isotope labeling technology used in the nitrogen uptake and utilization,providing a theoretical basis for the improvement of sugarcane nitrogen use efficiency and the efficient nitrogen fertilizer management of sugarcane.

^(15)N Isotope Used for Study of Groundwater Nitrogen Pollution in Shijiazhuang City, China

Shijiazhuang City is the capital of Hebei province, China. Groundwater is the major water supply source for living and industry need of the city. Due to a rapid increase of population and development of industry and agriculture, a series of groundwater environmental problems are created. In the paper, the situation of groundwater pollution in Shijiazhuang city is reported. Based on the groundwater chemical data and ^(15)N measurement results both on groundwater and soils, the reason of groundwater nitra...

Absorption spectra and isotope shifts of the(2, 0),(3, 1), and(8, 5) bands of the A^2Π_u-X^2Σ_g^+ system of ^(15)N_2^+ in near infrared

The high-resolution absorption spectra of the （2,0）,（3,1）,and （8,5） bands of the A^2Π^u-X^2∑g^＋ system of ^15N2^＋ have been recorded by using velocity modulation spectroscopy technique in the near infrared region.The rotational constants of the X^2∑g^＋ and A^2Πu states of ^15N2^＋ were derived from the spectroscopic data.The isotope shifts of these bands of the A^2Πu-X^2∑g^＋ system of ^14N2^＋ and ^15N2^＋ were also analyzed and discussed.

Investigation of Nitrite Production Pathway in Integrated Partial Denitrification/Anammox Process via Isotope Labelling Technique and the Relevant Microbial Communities

In this study,the nitrogen removal performance of partial denitrificaiton/anammox(PDA)process was investigated by using an UASB reactor.High total nitrogen(TN)removal efficiency(91.97%)was achieved at an influent nitrogen loading rate of 0.64 kg/(m3·d).Anammox bacteria did execute the function of converting nitrate to nitrite in PDA system according to ^(15)N isotope labeling experiments and the contribution was approximately 36.3%.Candidatus_Brocadia,Candidatus_Kuenenia and Thauera were functional strains for anammox and denitrification process,respectively.Thauera and Candidatus_Brocadia were more important for TN removal at high loading rates(0.64 kg/(m3·d)).This result can provide a theoretical and technical foundation for the application of the PDA process.

Trace element geochemistry and stable isotopic(δ^(13)C andδ^(15)N)records of the Paleocene coals,Salt Range,Punjab,Pakistan

The Paleocene coals of the Salt Range in the Punjab Province of Pakistan have great economic potential;however,their trace element and stable isotopic characteristics have not been studied in detail except for a few sporadic samples.In this study,a total of 59 coal samples of which 14 are obtained from open cast mines have been investigated for elemental composition andδ^(13)C-δ^(15)N isotopic signatures.Average contents of trace elements such as Co,Cr,Cu,Pb,Sr,Th,U,V,and Zn are 7.4,41.7,11.2,12.5,90.2,4.0,1.9,128,and 31.1 mg/kg,respectively.These values,when compared with the World Coal Clarke values,were relatively higher in low-rank coals in comparison with Clarke values for brown coals.Likewise,As(20.4 mg/kg),Co(6.6 mg/kg),Cr(22.4 mg/kg),Cu(^(13).3 mg/kg),Pb(19.2 mg/kg),Sr(^(15)4.7 mg/kg),Th(2.5 mg/kg),V(47.8 mg/kg),and Zn(75.1 mg/kg)were significantly higher in the sub-bituminous to bituminous coals of the Salt Range.Mineralogical analysis,based on X-ray diffraction and energy dispersive X-ray spectroscopy,revealed that the studied samples contain illite,kaolinite calcite,gypsum,pyrite,and quartz.Elemental affinity with organic and inorganic phases of coals calculated by an indirect statistical approach indicated a positive association of ash content with Ag,Al,Co,Cr,Cs,Cu,Mn,P,Rb,Pb,Th,U,and V,suggesting the presence of inorganic components in studied coals.However,As,Fe,Sr,and Zn exhibit negative correlations that imply their association with the organic fraction.Theδ^(13)C andδ^(15)N isotopic range and average−24.94‰to−25.86‰(−25.41‰)and−2.77‰to 3.22‰(0.96‰),respectively,reflecting 3C type modern terrestrial vegetation were common in the palaeomires of studied coal seams.In addition,the trivial variations of 0.92‰and 0.45‰among^(13)C and^(15)N values can be attributed to water level fluctuations and plant assemblies.

Stable isotopes in aquatic food web of an artificial lagoon in the Hangzhou Bay,China

Stable isotope values, δ13C and δ15N, were determined for four primary producers and 19 dominant consumers in a small artificial lagoon located in Hangzhou Bay. Based on these results the major pathways for energy flow and trophic structure of the artificial lagoon ecosystem were characterized. The mean δ13C values for the 19 consumers ranged from -22.99‰ to -14.24‰. Apart from so-iny mullet Liza haematocheila, the other 18 consumers had intermediate δ13C values between those of epibenthic microalgae and particulate organic matter (POM). The results of a multiple source linear mixing model (IsoSource model) indicated that 50% or more of the organic carbon in the tissues of most consumers was derived from epibenthic microalgae. This indicated that these primary producers were the main food source fueling the lagoon food web. The mean δ15N values for the 19 consumers varied between 4.93‰ and 12.97‰ and indicated four trophic levels in the lagoon. Four macroinvertebrates and zooplankton represented the primary consumers, whilst the other 14 consumers occupied the secondary and tertiary consumer levels. The 19 consumers were divided into three trophic guilds (detritivores/suspension feeders, omnivores and carnivores).

用^(15)N富积标记和稀释法研究旱作水稻/花生间作系统中氮素固定和转移

采用花生叶片15N富积标记法和15N同位素稀释法两种标记方法研究了水稻 花生间作条件下花生的生物固氮以及花生向水稻的氮素转移。盆栽结果表明,两种方法都证明在水稻花生间作的共生期内发生了氮素转移,花生固氮量的2%～3.5%转移到水稻体内。同位素稀释试验还表明,间作对花生固氮有促进作用,能提高其固氮效率(BNF)。本文还对两种同位素标记方法的优缺点进行了讨论。

^(15)N示踪技术在湿地氮素生物地球化学过程研究中的应用进展

稳定性同位素技术是现代生态学研究中的一门应用技术,它几乎在生态学研究的各个领域都有着广泛的应用。其中15N技术由于具有示踪和区分氮素物质的源与去向等优越性而在生态系统氮循环研究中发挥了极为重要的作用。文章主要从湿地氮素的输入过程、转化过程以及归趋过程三方面综述了该技术在当前国内外湿地氮素生物地球化学过程研究中的应用进展,特别指出当前基于该技术的湿地氮素生物地球化学过程研究尚缺乏一定的系统性、深入性和广泛性。最后,文章就该技术在湿地氮素生物地球化学过程研究中的应用前景进行了展望研究。

^(15)N同位素稀释法研究固氮菌接种对甘蔗生物固氮的影响

利用15N同位素稀释法,研究接种固氮菌klebsiella L03对甘蔗品种B8和ROC22的生物固氮的影响。结果表明:B8的固氮百分率最高为31.28%Ndfa,从苗期开始就显著高于ROC22,分蘖期和伸长初期的固氮量和固氮百分率与ROC22相比差异达到极显著水平。B8和ROC22的根、茎、叶都可发生固氮,以伸长初期(60d)叶片中的固氮能力最强。接种L03能显著提高B8和ROC22各器官的含氮量,其中对ROC22叶片和B8茎的含氮量提高作用最明显。不同甘蔗品种、相同品种的不同器官甚至相同器官的不同生长时期固氮作用有很大差异。

^(15)N自然丰度法在生态系统氮素循环研究中的应用

稳定性同位素技术是现代生态学研究中的一门新兴技术，在生态学研究的诸多领域都展示了广阔的应用前景。其中，稳定性同位素１５Ｎ自然丰度法近年来在生态系统氮素循环研究中发挥了和正在发挥着极为重要的作用。首先简述了自然生态系统氮素循环诸过程中的１５Ｎ同位素分馏机制。然后，在此基础上，综述了１５Ｎ自然丰度法的基本原理与方法，列举了近年来此法在生物固氮及氮素转化过程研究中的一些应用实例，并预测了该方法在国内氮素循环研究中的应用前景。

Estimation of Biological Nitrogen Fixation Capacity by Sugarcane Using 15N

[ Objective] The study aimed to reveal the biological nitrogen fixation capacity by sugarcane from Brazil under the ecological conditions of Guangxi, and to provide reference for study on the biological nitrogen fixation capacity by sugarcane and related generalization and application. [ Method] The ^15N isotopic fertilizer was solely applied on plants of three sugarcane cultivars planted in greenhouse with no other fertilizer forms applied, meanwhile virus-free stem seedling was regarded as control, to measure their biological nitrogen fixation capacity using ^15N isotope. [ Result ] The nitrogen fixation rate of B8 from Brazil reached 26.91%, while Guitang 11 and RIC16 presented no or poor nitrogen fixation capacity. [ Conclusion] The sugarcane eultivar B8 from Brazil showed some nitrogen fixation capacity under the ecological conditions of Guangxi.

L-^(15)N亮氨酸和质谱测定大鼠肝蛋白质合成

目的:建立稳定同位素L 15N亮氨酸测定大鼠肝蛋白质合成率的方法。 方法:分别测定静脉注射相同剂量L 15N亮氨酸不同时相的大鼠肝15N丰度及不同剂量L 15N亮氨酸同一时相的大鼠肝15N丰度。 结果:大鼠肝游离氨基酸池中15N同位素丰度在注射后30min内呈线性上升并达高峰,维持4h后缓慢下降,肝蛋白质中的15N丰度30min至12h基本维持不变;随着注射剂量的增加,大鼠肝蛋白质分数合成率亦增加,当L 15N亮氨酸剂量>1. 0mmol/kg,分数合成率并不随施加L 15N亮氨酸剂量的加大而增加。 结论:在进行大鼠肝蛋白质合成率测定时,一次性静脉注射的测量最佳时限为30min,剂量为1. 0mmol/kg。

15N同位素在华北冬小麦夏玉米氮营养来源研究中的应用

小麦-玉米一年两作是华北平原最主要的种植方式之一,对保障国家粮食安全至关重要。阐明该种植体系作物氮营养来源定量组成对区域养分资源管理、施肥制度优化、作物营养状况调控都具有十分重要的意义。15N作为氮元素的一种稳定同位素,其示踪技术在农田氮肥去向,作物氮营养来源等农业生产领域得到广泛应用。本文主要概述了15N同位素技术在研究当季施入化肥氮、前茬残留化肥氮、播前土壤固有硝态氮对华北冬小麦-夏玉米氮营养贡献中的具体应用方法、实例及相关研究结果,并对叶面肥氮、还田秸秆氮、大气沉降氮等其他氮营养来源的研究进行了展望,以期为该种植体系养分资源管理以及施肥制度优化提供理论参考。

稳定性同位素^(15)N在我国农业研究中的应用

对近年来稳定性同位素15N在农业研究中的应用及所取得的成就进行了综述 ,并展望了稳定性同位素15N在农业科学研究方面应用的发展前景。

应用^(15)N研究不同氮肥在麦田土壤中的去向及脲酶抑制剂的效果

研究以盆栽试验为主,并结合大田试验,利用^(15)N示踪法对我国南方两种土壤上尿素、硝酸铵不同氮肥的去向及脲酶抑制剂对氮肥去向的影响进行了细致研究。特别阐明了氨的挥发和氮素的淋溶损失动态状况。在黄棕壤上,尿素中氨的挥发损失率大于硝酸铵,分别为11.7%和8.1%,前者比后者大43.7%;而氮的淋溶损失率则相反,分别为0.70%和0.79%,硝酸铵淋溶损失率比尿素高11.4%。在红黄土上氨的挥发损失率比在黄棕壤上小,仅为5.3%。首次指出了这两种氮肥的挥发损失远大于淋漏损失的结果。查明了增施脲酶抑制剂对提高氮肥利用、减少氨的挥发损失的明显作用。

芳香族羟肟过渡金属配合物及其^(15)N同位素取代红外光谱位移和结构的研究

芳香族羟肟类化合物能与过渡金属离子螯合,已成功地应用于金属分析和湿法冶金。显然,此类配合物结构和键性质的研究对于了解反应机理和配位体的分子设计具有指导意义,已经开展了多方面的研究。作者曾报道了2-羟基-4(5)-取代二苯甲酮肟顺式(Syn)和反式(Anti)异构体的v_(OH)