摘要：在全球气候变暖的发展下，不同地区的农业气候资源随之发生变化，农业生产活动受到不同程度的影响，气温升高如何影响冬小麦土壤理化性质和丛枝菌根的变化还缺乏经验和证据。本试验以江苏省主栽品种扬麦13为研究对象，采用红外加热模拟增温结合外施氮肥的方法，分析研究了夜间增温和施肥对冬小麦丛枝菌根侵染率和真菌群落多样性的影响。结果表明: 夜间增温主要降低了AM真菌的侵染率，而提高了土壤中真菌群落多样性和均匀度，这可能与夜间增温降低了土壤中pH并提高了土壤中铵态氮含量有关；在N375处理下，增温的shannon指数从2.40显著提高到了3.43。施氮量的提高显著降低了成熟期AM真菌菌根侵染率，在增温处理中，随施氮量的增加，真菌群落的丰富性显著升高。夜间增温引起的土壤理化性质的变化降低了冬小麦对外生菌根的依赖性，提高了菌根真菌群落的多样性和均匀度，这为进一步研究该区域冬小麦地下过程对全球气候变化的响应机制提供了科学依据。

关键词：增温；施氮量；小麦；土壤养分；丛枝菌根

Effects of nighttime warming and nitrogen application rate on arbuscular mycorrhizal infection and persity in ryegrass

Abstract：With the development of global warming, agroclimatic resources in different regions have changed along with different degrees of agricultural production activities. How temperature increases affect the soil physical and chemical properties and arbuscular mycorrhizae changes in winter wheat still lacks experience and evidence. In this study, Yangmai No. 13 as the main cultivar in Jiangsu Province was used as the research object. Using infrared heating combined with simulated temperature-enhanced application of nitrogen fertilizer, the arbuscular mycorrhizal infection rate and fungal community persity of winter wheat under nighttime temperature increase and fertilization were analyzed. The results showed that nighttime warming mainly reduced the infection rate of AM fungi, and increased the persity and evenness of fungal communities in the soil. This may be related to the fact that nighttime warming reduces the pH in the soil and increases the content of ammonium nitrogen in the soil. Under the N375 treatment, the warming shannon index increased significantly from 2.40 to 3.43. The increase of nitrogen application rate significantly reduced the mycorrhizal infection rate of AM fungi in mature stage. During the warming treatment, the richness of fungal community increased significantly with the increase of nitrogen application rate. Changes in soil physiochemical properties caused by nighttime warming reduced the dependence on the ectomycorrhiza of winter wheat and increased the persity and evenness of the mycorrhizal fungal community. This will provides scientific evidence for further study in the response mechanism of the subsurface process of winter wheat to global climate change in the region.

Key words: Warming；Nitrogen Rates；Wheat；Soil Nutrients；Arbuscular Mycorrhizae

目  录

摘要1

关键词1

Abstract1

Key words1

引言1

1 材料与方法2

1.1 研究方法2

1.2 测定项目及方法2

1.2.1 根样采集2

1.2.2 土样采集3

1.2.3 土壤温湿度3

1.2.4 土壤理化性质测定3

1.2.5 AM真菌侵染率3

1.2.6 AM真菌丰富度和多样性3

1.3 数据处理3

2 结果与分析3

2.1 对麦田环境的影响3

2.1.1 对植株各层温度的影响 3

2.1.2 对土壤湿度的影响4

2.2对土壤理化性质的影响5

2.3 对AM真菌侵染率的影响5

2.4 对AM真菌多样性的影响6

2.5 土壤环境与AM生长发育的相关性分析7

3 讨论7

致谢8

参考文献8

夜间增温和不同施氮量对小麦田丛枝菌根侵染率和多样性的影响

IPCC(Intergovernmental Panel on Climate Change)第五次评估报告结合陆地和海洋表面温度资料的全球平均值显示，从1880至2012年温度升高了0.85℃，据预测，到2035年全球平均表面温度将升高0.3-0.7℃[1]。随着温室效应增强，全球气候变暖，农业生产也逐渐受到越来越大的影响。气候变暖增温主要发生在冬春季，土壤的增温幅度大于大气[2]，因而与小麦尤其是冬小麦的生长发育有较大关联。冬春季高温对冬小麦根系生长起促进作用，但会导致地上部生物量和养分累积量呈降低趋势[3]。同时，由于我国长期以来耕作中对氮肥的依赖，使得土壤环境较过去产生了显著的变化，出现了土壤酸化板结、富营养化、氮肥农学效率以及氮肥利用率降低等诸多问题，打破了土壤生态系统稳定性，对土壤环境构成威胁。丛枝菌根(Arbuscular mycorrhiza，AM)是宿主植物与丛枝菌根真菌在一定环境条件下相互作用，相互影响而形成的互惠共生体。AM真菌与宿主植物的共生关系能够促进宿主植物对磷素的吸收[4-5]、对氮素的利用[6-7]，并提高宿主植物的抗旱性[8-10]、抗盐性[11-12]，加强宿主植物耐高温能力[13]，增强宿主植物的抗病性[14]等，为宿主植物带来一系列益处。前人的研究发现，在现代高肥条件下培育的小麦品种同样与丛枝菌根关系紧密[15]，而丛枝菌根真菌的群落组成和生长发育与土壤温度的高低有直接关联[16]，并受到土壤氮素含量的显著影响[17]。所以研究气候变化和氮肥施用对土壤丛枝菌根真菌群落的影响有着重要的意义。