经营模式对毛竹林土壤细菌、真菌群落结构和丰度的影响

发布时间：2018-03-25 00:02

本文选题：毛竹林　切入点：粗放经营　出处：《浙江农林大学》2017年硕士论文

【摘要】：毛竹是中国亚热带地区重要的人工林,目前我国的毛竹林采用两种经营模式:粗放和集约经营。毛竹林粗放经营对土壤养分循环和微生物的群落结构产生重要影响。本研究以土壤细菌和真菌为对象,在毛竹主产区分别选择两处不同栽培年限的粗放和集约经营毛竹林样地,分别采集0-20cm和20-40cm土壤,通过荧光定量PCR技术分析了土壤细菌和真菌的丰度;PCR-DGGE技术和T-RFLP技术分析了土壤细菌和真菌的群落结构变化和多样性指数。旨在揭示毛竹林长期粗放或集约经营过程中土壤细菌和真菌的群落结构和丰度随经营时间增加的变化规律。取得的主要研究结果如下:(1)粗放经营毛竹林发展过程中,安吉土壤细菌丰度随着毛竹种植时间不断下降,而安吉土壤真菌以及长兴土壤细菌和真菌在毛竹纯林5年时丰度均显著增加,之后随种植地点的不同出现不同的变化规律。土壤细菌和真菌的群落结构均发生明显变化,且细菌结构对毛竹种植时间的响应更敏感,表层土壤细菌群落表现出抵抗干扰、恢复到初始结构的趋势。对DGGE结果的冗余分析的第一、二轴对样地变化的解释率大多低于65%,不同地点、不同土层驱动土壤微生物结构随时间变化的主要因子缺乏一致性,说明除本研究分析的5个土壤指标外还有其他性质驱动微生物结构的变化,是多因子共同作用导致细菌和真菌的变化。对T-RFLP结果的冗余分析说明,影响土壤细菌和真菌的群落结构的因素依次是地区、土层和毛竹种植时间,说明毛竹林土壤细菌表现为明显的地域差异。(2)集约经营毛竹林发展过程中,土壤养分表现为富集现象。遂昌和长兴两地细菌和真菌的丰度表现出不同的变化规律,遂昌土壤细菌随时间增加丰度变化不大,仅亚表层土壤在25年时显著上升;而真菌则在前15年时随时间增加而下降,15年后又上升。长兴土壤细菌呈现出稳定的周期性变化,而真菌则在集约经营5年时发生变化,5年之后丰度保持稳定。说明土壤细菌和真菌的丰度变化规律有明显的地域性差异,随时间的增加细菌的数量更趋向于稳定,而真菌的数量在长时间的集约经营后上升。PCR-DGGE结果表明,集约经营后的发展过程中细菌的多样性变化发生在经营中后期,而真菌的群落结构变化发生在经营前期。真菌受到环境因子的影响大于细菌,且细菌表现出抵抗干扰、恢复群落结构的能力。对T-RFLP结果的冗余分析表明,影响同一地区细菌、真菌结构的理化性质较为统一,其中pH在细菌和真菌的群落变化过程中起到了关键作用;地域差异对细菌和真菌群落的影响大于不同土层之间的影响,而不同土层的影响大于不同经营时间的影响。
[Abstract]:Phyllostachys pubescens is an important plantation in subtropical China. At present, there are two kinds of management models of Phyllostachys pubescens forest in China: extensive and intensive management. Extensive management of Phyllostachys pubescens forest has an important effect on soil nutrient cycling and microbial community structure. In the main production area of Phyllostachys pubescens, two extensive and intensive plots with different cultivation years were selected to collect 0-20cm and 20-40cm soil, respectively. The abundance of soil bacteria and fungi was analyzed by fluorescence quantitative PCR and T-RFLP. The community structure change and diversity index of soil bacteria and fungi were analyzed in order to reveal the long-term extensive or intensive management of Phyllostachys pubescens forest. The community structure and abundance of soil bacteria and fungi increased with the management time. The main results were as follows: 1) during the extensive management of Phyllostachys pubescens forest, The bacterial abundance of Anji soil decreased with the planting time of Phyllostachys pubescens, while the soil fungi and fungi in Anji soil and Changxing soil increased significantly in 5 years of pure bamboo forest. The community structure of soil bacteria and fungi changed obviously, and the bacterial structure was more sensitive to the planting time of Phyllostachys pubescens, and the bacterial community in surface soil showed resistance to interference. In the redundancy analysis of DGGE results, the rate of interpretation of the variation of soil samples was mostly lower than 65. In different sites, the main factors driving soil microbial structure in different soil layers were not consistent with each other over time. In addition to the five soil indicators analyzed in this study, there are other properties that drive the change of microbial structure, which is caused by the interaction of many factors. The redundancy analysis of T-RFLP results shows that, The factors influencing the community structure of soil bacteria and fungi were region, soil layer and planting time of Phyllostachys pubescens, which indicated that soil bacteria in Phyllostachys pubescens forest showed obvious regional difference. 2) during the development process of intensive management of Phyllostachys pubescens forest. The abundance of bacteria and fungi in Suichang and Changxing showed different changes. The abundance of bacteria in Suichang soil changed little with time, but the subsurface soil increased significantly in 25 years. However, fungi decreased with time in the first 15 years, and then increased 15 years later. The bacteria in Changxing soil showed stable periodic changes. But fungi changed during intensive management for 5 years and kept stable after 5 years, which indicated that the variation of soil bacteria and fungi abundance had obvious regional difference, and the number of bacteria tended to be stable with the increase of time. The number of fungi increased after intensive management for a long time. The results of PCR-DGGE showed that the diversity of bacteria in the development process of intensive management occurred in the middle and late stage of operation. The changes of fungal community structure occurred in the early stage of operation. The fungi were affected by environmental factors more than bacteria, and bacteria showed the ability to resist interference and restore the community structure. The redundancy analysis of T-RFLP results showed that the bacteria affected the same area. The physical and chemical properties of fungal structure were uniform, and pH played a key role in the change of bacterial and fungal communities, and the influence of geographical differences on bacterial and fungal communities was greater than that on different soil layers. The influence of different soil layer is greater than that of different management time.
【学位授予单位】：浙江农林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S795.7;S714.3

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