IMHE OpenIR  > 山地表生过程与生态调控重点实验室
贡嘎山垂直梯度带土壤微生物特征及其与磷的关系
Alternative TitleSoil Microbial Communities and Its Relationship With Phosphorus along Altitudinal Gradient of Gongga Mountain
Language中文
孙宏洋
Thesis Advisor吴艳宏
2014
Degree Grantor中国科学院研究生院
Place of Conferral北京
Degree Name博士
Degree Discipline自然地理学
Keyword磷形态 溶磷微生物 Plfa 海拔梯度 高山环境
Abstract磷是维持和提高生态系统的生产力的关键元素之一,但土壤中生物有效磷含量极低,大部分磷以固相形式存在,并且工业社会带来的氮素沉降的增加和大气中碳素的积累导致的元素化学计量平衡破坏,使得磷素成为仅次于氮素的植物第二大限制性营养元素。在土壤中,生物有效磷的耗竭会降低植物生长速率、限制土地的初级生产力和阻碍生态系统的发展演化。在陆地生态系统中,生物量磷主要来源于岩石中磷的风化释放。作为一典型的陆地生态系统,高山生态系统因为陡峭的坡度、土壤风化程度低以及浅薄的土层,使得磷的来源非常依赖与岩石磷的风化释放。然而,土壤微生物对岩石磷的风化释放能维持土壤中生物有效磷水平。因此,土壤微生物群落的溶磷功能对高山生态系统生物有效磷的供应起到至关重要的作用。此外,世界磷矿资源在迅速的耗竭,这会使世界粮食问题产生急剧的恶化。英国《泰晤士报》发表文章警告世界“全球至关重要的磷或将短缺”,并且称,按照目前的消费速度,可开采的磷矿将在今后50—100年内消耗殆尽,还暗示磷矿资源将与石油资源媲美,产生新的“资源超级大国”形成新的地缘政治图。面对因磷产生的生态系统问题和农业生产问题,许多科研工作者把希望寄托于土壤微生物磷素地化作用的研究。因此,研究生态系统中磷的地球化学规律及其与微生物的关系十分必要的。 本研究以贡嘎山东坡垂直梯度带上地带性根际土为研究对象,依靠土壤理化属性测定技术、土壤磷组分连续提取技术、微生物PLFA测试技术、溶磷微生物分离测试技术以及对溶磷微生物群的碳氮添加试验,查明了贡嘎山东坡垂直梯度带上磷组分分布特征、微生物群落结构特征以及它们之间的相关性,确定了影响微生物群落海拔分布的主要磷形态;摸清了溶磷微生物资源的分布概况;并评估了碳氮元素对微生物群落溶磷功能的影响。主要结论如下: 1、在贡嘎山微生物量磷随海拔分布符合抛物线趋势,并且在海拔3500m以下,降水和植被类型是影响微生物量磷浓度的主要因素,在海拔3500m以上,温度、降水和植被类型控制着微生物量磷分布。树脂提取态无机磷(Resin-Pi)浓度有随海拔增加而减少的趋势。在各海拔带上,相对于氢氧化钠提取态有机磷(NaOH-Po)和盐酸提取态有机磷(HCl-Po),氢氧化钠提取态无机磷(NaOH-Pi)和盐酸提取态无机磷(HCl-Pi)浓度相对稳定。与生物有效性磷组分相比(Resin-Pi和碳酸氢钠提取态无机磷NaHCO3-Pi),NaOH-Pi和HCl-Pi都与微生物量磷有更显著的线性关系。这个结果表明在微生物和土壤矿物长期的相互作用下这些不可利用磷组分可以逐渐转变为生物有效磷组分。此外,与其他变量相比,HCl-Pi和pH能构成更好的线性模型预测土壤中微生物量磷浓度 2、尽管土壤微生物总磷脂脂肪酸(Phospholipid fatty acid,PLFA)浓度沿海拔梯度没有显示出明显的规则趋势,但许多微生物特征PLFA结果表明一些土壤微生物沿海拔分布格局有生物地带性特征,这一格局最可能沿海拔带城抛物线型。冗余分析和相关分析表明在所研究的样地中一些磷形态 (如HCl-Pi和碳酸氢钠提取态有机磷NaHCO3-Po)对微生物PLFA分布的影响和土壤湿度、土壤pH一样重要。此外,我们的结果表明从土壤原生矿物中释放的磷在维持贡嘎山生态系统生物有效磷供应起着重要的作用。 3、贡嘎山海拔梯度带根际土中有丰富的溶磷微生物资源。从最低磷浓度上看,海拔4086m和海拔2032m上存在着较为优良的低磷适应细菌。 在海拔2777m的植被带中最可能找到优良的低磷适应真菌,而在海拔4223m的植被带中有较少的低适应真菌。海拔4086m和海拔2032m上存在着较为优良的溶磷细菌。4223m和2360m有较为优良的溶磷真菌。细菌滤液中可溶性无机磷浓度与pH之间有极显著的幂函数关系,而真菌培养液滤液中可溶性磷浓度似乎与pH关系不大。真菌分泌的有机酸对金属离子的络合、真菌对钙离子的富集以及真菌巨大的生物量对磷的累积可能是实验中重要的溶磷机制。 4、高山环境下不同海拔植被条件下微生物群落对碳氮添加的响应是有差异。不仅碳氮比会对微生物种群和溶磷能力产生影响,而且碳氮水平也会对微生物造成显著影响,并且来自不同土壤的微生物群落响应也存在显著差异。当氮添加量恒定为6.2mg时,三种微生物群落的溶磷能力随碳氮比的增加而增强。当碳添加量恒定为364mg时,中海拔微生物群落(ME)和低海拔微生物群落(LE)的溶磷能力随碳氮比降低而升高。然而,对于HE群落有不同的效应发生,这个群落在中碳氮比条件出现了最低溶磷值。在低和高碳氮比时,高水平的碳氮都能增强各微生物群落的溶磷效果。高海拔群落(HE)在碳氮比为6.2条件下对高碳氮水平敏感,其PO43-浓度显著提升。我们的结果暗示中碳氮比下高水平碳氮水平容易增强HE溶磷微生物群落的代谢活性来提升溶磷能力,而对于ME溶磷微生物群落而言高碳氮比下高水平碳氮水平容易增强其代谢活性来提供其溶磷能力。微生物群落结构和代谢活性的变化是解释这些试验响应的进一步原因。
Other AbstractPhosphorus (P) is an essential element which maintains and increases the primary productivity of terrestrial ecosystems. However, most of soil P is in the form of solid phase, and bioavailable P content is very low in soils. Moreover, industrial emissions increased nitrogen deposition and atmospheric carbon accumulation, and it can disturb stoichiometric balance of elements in ecosystems. In soil, bioavailable P deficiency can reduce plant growth, limit primary productivity and hinder ecosystem development. In terrestrial ecosystems, P in biomass mainly comes from rock weathering. As a typical terrestrial ecosystem, alpine ecosystems are very dependent on the P source from rock weathering due to the steep slope, young soil and thin soil layer here. However, microorganisms can maintain the bioavailable P level of soil by solubilizing rock phosphates. Therefore, phosphate solubilizing function of soil microbial community may plays a vital role in bioavailable P supply for alpine ecosystems. In addition, phosphorite resources is rapidly depleted, and it can make a sharp deteriotation of the global food problems. The Times warned the world that the essential P will be exhausted, and mineable phosphate will be depleted in 50-100 years at the current rate of consumption. The Times also indicated that the P resources would be as important as petroleum, and it can produce new “Resources Superpower” and new formation of geopolitical. To solve these problems, many researchers put their hopes on microbial P geochemical studies. Therefore it is very essential to study the relationships between soil microoganisms and P geochemical cycle. In the present study, rhizosphere soils along east slope of Gongga Mountain were studied using soil physical and chemical properties measurement, sequential chemical extractions for soil P, microbial PLFA analysis techniques, phosphate-Solubilizing microbial separation and test technology and a experiment of effect of carbon and nitrogen on phosphate-Solubilizing microorganism. We found out the distribution pattern of soil P fraction, microbial community structure and their correlation. The main P fraction affecting microbial distribution along an altitudinal gradient was determined. The distribution information of phosphate-Solubilizing microorganisms was get. Moreover, response of phosphate-solubilizing microbial community from alpine ecosystems to carbon and nitrogen ratios and levels in phosphate solubilizing ability was assessed. In the present study, the main conclusions were as follows: 1. The MBP distribution with elevation at Gongga Mountain followed a parabolic trend. Below approximately 3500 m asl, rainfall and vegetation type were the main factors that affected the MBP concentrations. Conversely, above 3500 m asl, temperature, rainfall and vegetation type controlled the MBP distribution at Gongga Mountain. The Resin-Pi concentrations in the six vegetation zones decreased with increasing altitude. The NaOH-Pi and HCl-Pi concentrations were stable with increasing altitude relative to the NaOH-Po and HCl-Po concentrations. Compared with the bioavailable P fractions (Resin-Pi and NaHCO3-Pi), both NaOH-Pi and HCl-Pi have more significant linear relationships with MBP. The result suggests that the non-bioavailable P fractionations may turn into the bioavailable P with the long-term interaction between microorganism and soil minerals. In addition, HCl-Pi and pH comprised a good linear model which predicts the MBP concentration compared with other variables. 2. Although the total PLFA concentration displayed no regular trend with elevation, many biomarker PLFAs indicated that there were biogeographic trends of the microbial distribution patterns of some soil microorganisms, which were most often parabolic patterns along the elevation gradient. A redundancy analysis (RDA) and correlations revealed that some of the phosphorus fractions(HCl-Pi and NaHCO3-Po) are as important as soil moisture and pH for in
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/7933
Collection山地表生过程与生态调控重点实验室
Affiliation孙宏洋
Recommended Citation
GB/T 7714
孙宏洋. 贡嘎山垂直梯度带土壤微生物特征及其与磷的关系[D]. 北京. 中国科学院研究生院,2014.
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