| 题名 | 施氮对不同有机碳水平桉树人工林土壤微生物群落结构和功能的影响 |
| 作者 | 苏丹 |
| 学位类别 | 硕士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 郑华 |
| 关键词 | 桉树 施氮 有机碳 土壤微生物 群落结构和功能 Eucalyptus nitrogen application soil organic carbon soil microbial communities and functions |
| 其他题名 | Effects of nitrogen application level on soil microbial community structure and function in Eucalyptus plantations with different soil organic carbon levels |
| 学位专业 | 生态学 |
| 中文摘要 | 碳、氮是影响土壤微生物群落结构和功能的两种重要生源要素，围绕施氮对人工林土壤微生物群落的影响已经开展了很多研究，但这些研究很少考虑土壤有机碳水平差异对研究结果的影响。本研究以我国南方桉树人工林为对象，研究施氮水平（对照：0 kg∙hm-2，常规施氮水平166.8 kg∙hm-2，施二倍氮素水平333.7kg∙hm-2）对土壤有机碳水平显著不同的两桉树林土壤微生物群落结构（磷脂脂肪酸构成）和功能（土壤酶活性，土壤微生物群落碳代谢功能）的影响。结果表明： （1）施氮显著影响了土壤微生物群落结构和功能（P<0.05）：施氮显著降低土壤微生物群落磷脂脂肪酸总量以及细菌、真菌、放线菌磷脂脂肪酸量和真菌/细菌比值（P<0.05）；施氮显著促进了土壤纤维素酶、酚氧化酶活性活性（P<0.05），而随着施氮水平的升高，土壤微生物群落碳代谢强度和代谢碳源丰富度均呈现显著的先增加后降低的变化规律(P<0.05)。 （2）不同土壤有机碳水平下，桉树林土壤微生物群落结构及功能差异显著：与低有机碳水平土壤样地相比，高土壤有机碳样地中土壤微生物磷脂脂肪酸含量以及土壤微生物土壤微生物群落碳代谢强度、代谢碳源丰富度与土壤酶活性显著较高（P<0.05）。 （3）施氮和土壤有机碳水平对土壤微生物群落结构和功能的影响存在显著的交互作用（P<0.05）：与高有机碳水平土壤样地相比，低有机碳水平土壤样地土壤微生物群落结构和功能对施氮强度更敏感，细菌、真菌磷脂脂肪酸含量在相对较低的施氮强度下显著降低，土壤酚氧化酶、土壤可溶性有机碳含量则在相抵较低的施氮强度下显著增加；但低有机碳水平土壤样地中纤维素酶、葡糖苷酶活性及土壤微生物碳代谢功能对施氮的响应不显著。表明土壤微生物群落结构、功能特征与土壤氮素水平、有机碳水平均密切相关。 （4）区分不同处理的土壤微生物磷脂脂肪酸主要是：真菌特征脂肪酸16:1ω5c、18:1ω9c、18:2ω9c及细菌特征脂肪酸16:1ω7c、 i17:0和放线菌特征脂肪酸10Me18:0；施氮主要影响的代谢碳源主要是碳水化合物类、氨基酸类和羧酸类等碳源，土壤微生物生物量是影响土壤微生物碳代谢强度和代谢碳源丰富度的重要因素。 该研究发现施氮显著影响土壤微生物群落结构和功能，而且这种影响在不同土壤有机碳水平桉树林中的表现不一致。这表明人工林土壤有机碳水平显著影响施氮对土壤微生物群落的效应，在探讨人工林土壤微生物群落对施氮的响应时，除了考虑施氮的水平以外，土壤有机碳水平也不容忽视。 |
| 英文摘要 | Soil microorganisms are involved in the turnover of nitrogen and other nutrients, which are sensitive to soil nutrient content changes. Nitrogen and carbon, two basic nutrients in soils, directly influence the structure and function of soil microbial communities. Similarly, the soil organic carbon, the main energy source of soil microorganisms, play a key role in mediating soil microbial activity. However, few studies focus on the combined effects of nitrogen level and soil organic carbon level on soil microbial communities. To illuminate the effects of nitrogen level and soil organic carbon level on soil microbial function, for the soil system and microbial community compositions (phospholipid Fatty-acid Analysis, PLFA) and functions(based on the indexes of soil extracellular enzyme activity and soil dissolved organic carbon (DOC)contents), We conducted the field experiment with 3 nitrogen addition levels (CK:0 kg∙hm-2, normal nitrogen level NN:166.8 kg∙hm-2，the double nitrogen level HN: 333.7 kg∙hm-2) and in two Eucalyptus plantation sites with different soil organic carbon levels (low organic carbon site (LC) and high organic carbon site (HC)) in Guangxi, southern China. (1) Nitrogen application had significant influence on soil microbial community structure and function(P<0.05).The total PLFAs, the PLFAs of bacteria, fungi, actinomycetes, and the ratios of fungi / bacteria decreased with the increase of nitrogen application; Cellulase and phenol oxidase activities, and soil organic DOC significantly increased with nitrogen application；Soil microbial carbon metabolism was significantly influenced by nitrogen level (P< 0.05). With the increase of nitrogen level, soil microbial carbon metabolism intensity and richness increased gradually and then decreased gradually. (2) Soil microbial carbon metabolism function was Positively response to the organic carbon levels(P<0.05). Carbon metabolism intensity and richness of soil microbial communities HC sites were significantly higher than those in LC sites (P< 0.01); Cellulase and Phenol oxidase activities, and soil organic DOC significantly increased with nitrogen application. Soil microbial PLFA, soil extracellular enzyme activity and soil DOC are significantly higher in the sites with high soil organic carbon content than those in the sites with low soil organic carbon content． (3) However the responses of soil microbial communities composition and functions to nitrogen are different in the two sites. The responses of the indexes to nitrogen are more sensitive in low soil organic carbon status sites, while the indexes are only changed with the HN level in high soil organic carbon status sites; Carbon metabolism intensity and richness of soil microbial communities in Eucalyptus Plantations with different soil organic carbon levels Presented significantly different responses to nitrogen level. In HC site with MN level, the maximum carbon metabolism intensity and richness of soil microbial communities was found, which was also observed in LC site with NN level. The interact effects of nitrogen level and organic carbon level on soil microbial metabolism is significant (P<0.01). (4)Fatty-acid 16:1ω5c, 18:1ω9c, 18:2ω9c, 16:1ω7c, i17:0 and 10Me18:0 distinguished the soil microbial communities under different nitrogen application treatments; The main carbon sources of the soil microbial metabolism, which differentiated the responses of the soil microbial metabolism function to nitrogen level, were carbohydrate, amino acid and carboxylic acids. Soil microbial biomass carbon Positively correlated with carbon metabolism intensity and richness index of soil microbial communities. Our results suggested that not only nitrogen level but also soil organic carbon level influence soil microbial community structure and function, and soil organic carbon level couldn’t be neglected in analyzing the effects of nitrogen level on soil microorganism community. |
| 公开日期 | 2015-07-07 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/15719]  |
| 专题 | 生态环境研究中心_城市与区域生态国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 苏丹. 施氮对不同有机碳水平桉树人工林土壤微生物群落结构和功能的影响[D]. 北京. 中国科学院研究生院. 2014. |
| 个性服务 |
| 查看访问统计 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
修改评论