4年O3熏气对小麦根际土壤氮素微生物转化的影响

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 四年O3熏气对小麦根际土壤氮素微生物转化的影响 DOI: 10.5846/stxb201301040015 作者: 作者单位: 南京信息工程大学环境科学与工程学院,南京信息工程大学环境科学与工程学院,南京信息工程大学环境科学与工程学院,南京信息工程大学环境科学与工程学院,南京信息工程大学环境科学与工程学院 作者简介: 通讯作者: 中图分类号: 基金项目: 教育部高等学校博士学科点专项科研基金资助项目（20123228110003）；国家自然科学基金资助项目（41075114） Induced changes in soil microbial transformation of nitrogen in maize rhizosphere by 4-year exposure to O3 Author: Affiliation: Nanjing University of Information Science Technology,Jiangsu Key Laboratory of Atmospheric environmental monitoring and Pollution control high-tech research,Nanjing University of Information Science Technology,Jiangsu Key Laboratory of Atmospheric environmental monitoring and Pollution control high-tech research,Nanjing University of Information Science Technology,Jiangsu Key Laboratory of Atmospheric environmental monitoring and Pollution control high-tech research,Nanjing University of Information Science Technology,Jiangsu Key Laboratory of Atmospheric environmental monitoring and Pollution control high-tech research,Nanjing University of Information Science Technology,Jiangsu Key Laboratory of Atmospheric environmental monitoring and Pollution control high-tech research Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:采用开顶箱（open top chambers，OTC） 法设置3个臭氧浓度梯度，连续4a对小麦生长季土壤进行臭氧增加试验。测定小麦拔节、孕穗、抽穗、灌浆和成熟期的根际土壤微生物量氮、氨氧化细菌、反硝化细菌数量以及硝化和反硝化强度。结果显示微生物量氮、氨氧化细菌数量和硝化强度随小麦生育进程的推进，呈先升高后降低的趋势，4a变化趋势相同。O3胁迫下，小麦根际微生物量氮、氨氧化细菌数量、硝化强度亦降低，与对照比较，均达显著水平（P < 0.05）；随O3作用年限增加，抑制效应越强，第4年 O3对其的抑制率显著高于第1年的抑制率。反硝化细菌数量在前期没有显著变化，成熟期则增加两个数量级，O3显著促进成熟期反硝化细菌数量增加。4a试验有相同的变化趋势。在较短时间里O3对土壤反硝化强度没有显著影响，而作用3个生长季后，反硝化强度显著升高。结果说明，O3浓度升高降低了麦田土壤微生物量氮、氨氧化细菌数量和硝化强度，并有一定的积累效应。O3剂量和作用时间的累积量达到一定阈值，显著增加土壤反硝化细菌数量和反硝化强度，增加麦田土壤N2O排放的风险。土壤氮素微生物转化受小麦生长发育状况和O3剂量、作用时间的共同影响，不同形态的氮素对O3的敏感阈值不同，响应的时间和变化的范围有差异。 Abstract:For determining changes in soil microbial transformation of nitrogen in a crop rhizosphere under ozone(O3)stress, using ozone treatments in OTCs (open top chambers), the effects of increase atmospheric surface level O3 contents on soil microbial transformation of nitrogen in winter wheat (Triticum aestivum)rhizosphere was investigated, during the growing/development (G/D) periods including reviving, jointing, booting, heading, filing and maturing stages. Four independent experiments were performed in four years, each for one year,using six OTCs. The chambers were equivalent, but two were fed with air while the other four with ozone at different concentration, in that two chambers with 100 nL/L and the other two with 150 nL/L. Winter wheat were grown to all life stage in OTCs. From reviving to mature stages, the plants were treated for 8 h (8:00-16:00) in every sunny day with different dose of O3, respectively. Soil microbial biomass N, amount of ammonium-oxidizing bacteria and denitrifying bacteria, soil nitrifying and denitrifying capacity were measured. Each treatment was assayed in triplicate. The data were initially compared by analysis of variance and differences between means were detected using the Duncans Multiple Range Tests. Values of P < 0.05 indicated significance. Quite similar results were obtained during the four years' experiments, suggesting that as a G/D stage is progressing, soil microbial biomass N, amount of ammonium-oxidizing bacteria and soil nitrifying capacity increased firstly but consequently declined. Under increased O3 stress, either soil microbial biomass N, or amount of ammonium-oxidizing bacteria or nitrifying capacity were found dropped. Their differences compare to control were significant (P < 0.05). With the increased of O3 dosage, the inhibition effects were found increasing. Inhibition rate of soil microbial biomass nitrogen, amount of ammonium-oxidizing bacteria and nitrifying capacity on wheat growth stages in the fourth years were significantly higher than those of the first year. The number of denitrifying bacteria was found to be no significant change in the earlier stages, but increased two orders of magnitude in the maturing stage. In maturity stage, the quantity of denitrifying bacteria was significantly improved by O3.Four years test showed the same change trend. No obvious influence of O3 on soil denitrifying capacity was found under short time ozone fumigation, but significantly increased during the later three growing seasons. Taking together,the elevated O3 concentration in atmospheric surface layer, impinges on the features of soil microbial transformation of nitrogen. O3 stresses can reduce soil microbial biomass N, amount of ammonium-oxidizing bacteria and nitrifying capacity. Enhance O3 irradiation and prolong fumigation time the Inhibition efficiency was up-regulated. When the cumulant of O3 dose and fumigation time reached a certain threshold, the number of denitrifying bacteria and denitrifying capacity rose up, meanwhile soil N2O emission risk was heighten. The effects on nitrogen microbial transformation were found to relate to (G/D) periods of winter wheat, dose of O3 and the exposure time. The different forms of nitrogen have different O3-sensitive, indicating that the threshold of subjected to O3, the responses time to O3 stress and the variation scope are different. 参考文献 相似文献 引证文献