【作者】 张瑜斌；

【导师】 林鹏；

【作者基本信息】 厦门大学 ， 植物学， 2002， 博士

【摘要】 红树林（mangroves）是自然分布于热带、亚热带海岸的潮间带的木本植物群落。微生物是生态系统的组成成分、最主要的分解者，推动着生态系统的物质循环与能量流动。本文通过经典的微生物学和生态学的实验手段，利用生物统计分析方法，研究了亚热带的九龙江口红树林区0—60cm土壤层的细菌、放线菌与丝状真菌3大类异养微生物数量的垂直分布、季节动态和区系；土壤环境因子的动态及其与士壤微生物数量动态的关系；红树林区红藻鹧鸪菜（Caloglossa）上异养固氮菌的季节动态和区系，异养固氮菌的季节动态与藻体营养元素的关系；优化了微生物学中经典的分离方法在红树林区的应用；测定了红树林土壤微生物的抗菌活性。1． 首次系统研究了稀释平板法中盐度对红树林土壤微生物数量的影响，结果表明 培养基盐度与稀释水盐度对红树林土壤微生物的数量有明显影响。分离培养基 的盐度增加会降低微生物的数量，培养基不宜用海水配制，放线菌培养基盐度 不宜高于5‰，丝状真菌和细菌分离培养基盐度宜控制在低盐度范围，二者可分 别控制在10‰以内和5～15‰的范围，细菌用无菌海水作稀释水的效果优于无 菌淡水，而放线菌和丝状真菌却是用无菌淡水作稀释水要优于无菌海水，根据 细菌、放线菌和丝状真菌的数量对培养基和稀释水盐度的反映，推断红树林区 土壤细菌、放线菌和丝状真菌多数为陆栖起源。2． 首次系统地研究了两类亚热带红树林0—60cm 3个层次土壤主要化学因子的垂 直分布与季节变化，结果表明： （1）红树林土壤有机质的垂直分布模式反映了根系的分布状况，在地表根系发达 的白骨壤（Avicennia marina）林，表层土壤有机质含量高，而在地表少根而 根系多集中分布于中层的秋茄（Kandelia candel）林，中层有机质含量高， 下层土壤有机质含量一般较低。全氮与有机质含量的垂直分布不完全一致可 能与土壤有机质的分解状况有关。两个红树林土壤的有机质大体上表现出冬 季含量最高，夏季最低，春秋两季位于之间的模式，而全氮含量则刚好相反， 有机质和全氮含量的季节变化模式反映了土壤异养微生物作用的季节性变 化。秋茄林与白骨壤林土壤全磷含量均随土壤深度增加而下降，但在垂直分 布上的差异较小，两个红树林土壤全磷含量春季均要稍微偏高，可能与此时 磷的外源输入有关。两个红树林土壤C/N值和N/P值的垂直分布与季节变化 极大程度上取决于全氮的变化。土壤全钾、全钙、全镁含量的垂直分布与季 节变化具有一定的随机性，这种情况在红树林区是否具普遍性尚不能定论。 两个红树林土壤盐分与全钠含量垂直分布的吻合缘于红树林土壤盐度及钠 元素的主要来源都是海水，盐分和全钠的垂直分布与士壤质地及其植物根系 的分布状况有关，冬季少雨而淡水注入量少，浸润红树林土壤的海水盐度要 高，且冬季干燥而蒸发量大导致了土壤盐分与全钠含量冬季最高。两个红树 林土壤的pH值有随深度增加而升高的趋势，这可能是随深度增加，土壤O2 含量减少之故，pH值没有一致的季节模式，但季节变异系数较小，反映了 红树林土壤对pH变化有一定的缓冲能力。 （2）红树林土壤养分优于相应的对照光滩，红树林与其对照光滩土壤主要化学因 子间的水平差异主要是红树植物引起的。秋茄林与白骨壤林土壤化学因于间 的水平差异，主要是潮位差异引起的，其次是两个红树林间特定的植物种类 差异及微生物作用的差异。 O＿．；。、＿．；、、，＿＿。＿。。＿、，。1＿。＿。。，、＿．＿＿—．．＿。。＿，。—…一 （3）土壤主要化学因于间的相关分析表明：4个位点内C／N值与N／P值的变化极 大程度上取抉于全氮。两个红树林土壤盐分与全钠均有极显著的正相关性， 是因为红树林土壤盐分及钠主要来源是海水，而钠是海水和土壤盐分中含量 最高的阳离于。以4个位点为基准而统计的土壤主要化学因于间的相关性表 明氮与有机质有相同的来源，而磷的来源除土壤有机质外，可能还存在其他 来源，但磷的行为与氮有联系，红树林土壤缺磷可能与土壤中有较高的钾、 钠、钙、镁与盐分含量有关。土壤全钾、全钠、全钙、全镁与盐分有相同的 主要来源一海水，它们的变化极大地受海水盐度的影响。相关分析也表明PH 值的影响因素复杂，土壤系统对pH值的变化具有一定的缓冲能力。 3．首次全面研究了红树林0—60cm 3个层次的土壤细菌、放线菌和丝状真菌数量 的垂直分布和季节变化及其与土壤主要化学因子的关系，结果表明： （l）秋茄林与白骨壤林土壤及其相应的对更多还原

【Abstract】 Mangrove forests are woody plant communities in the intertidal regimes of tropical and subtropical coasts. Microorganisms are compositions and main decomposers of ecosystem, which promote material cycle and energy flow in ecosystem. In this thesis, it was detailed studied with some classical microbiological and ecological experimental means’ and biological statistical methods that vertical distribution and seasonal changes of microbial counts and microflora of bacteria, actinomycetes and fungi in three soil layers from 0 to 60 cm in mangroves of Jiulongjiang Estuary, Fujian of China; It was also investigated that relation between soil environmental factors and counts of soil microorganisms, seasonal changes and microflora of heterotrophic nitrogen-fixing bacteria on Caloglossa body in mangroves, relation between seasonal dynamics of heterotrophic nitrogen-fixing bacteria and nutrient elements of Caloglossa sample, and antimicrobial activity of soil microorganisms in mangroves. In addition, dilution plate method was improved when it was applied in mangrove area.1. Effect of salinity on microbial counts of mangrove soil was first systematical investigated by dilution plate method, and the results indicated that the effect of salinity of media and dilution water on microbial counts of mangrove soil was significant. The seawater was not suitable for the preparing media because the increase of salinity of media would decrease the microbial counts of mangrove soil. The salinity of media should be at low concentrations, which should be within 5%o, 10%o and 5-15%o for actinomycetes, fungi and bacteria respectively. The effect of seawater was better than that of freshwater for bacterial isolation when both were respectively served as sterile dilution water. However, as was contrary to actinomycetes and fungi. It was concluded that most bacteria, actinomycetes and fungi of soil in mangrove area were terrestrial origin according to their effect of salinity of media and dilution water on isolation counts.2. Vertical distribution and seasonal changes of main chemical factors in three soil layers from 0 to 60 cm were first systematical investigated in two subtropical mangrove forests. The results showed as following:(1) The pattern of vertical distribution of organic matter in mangrove soil reflected the roots distribution. Surface roots were abundant in Avicennia marina forest, so organic matter of soil in top layer (0-20cm) was the most there. However, the organic matter of soil in Kandelia candel forest was the most in middle layer (20-40cm)because roots were abundant in middle layer while there were fewer roots on surface soil. Content of organic matter in bottom layer (40-60cm) was generally lower in two mangrove forests. Vertical distribution of total nitrogen and organic matter was not completely identical, which was related with decomposition of soil organic matter. Content of soil organic matter in two mangrove forests was generally the highest in winter and the lowest in summer, and that in spring and autumn were between winter and summer, but as was contrary to total nitrogen. Seasonal patter of organic matter and total nitrogen reflected seasonal changes of the activity of heterotrophic soil microorganisms. The concentration of total phosphorus in mangrove soil decreased with increase of soil depth, but the variation on vertical distribution was little. The concentration of total phosphorus in mangrove soil was somewhat higher in spring, which was probably related with input of phosphorus from outer environment. Vertical distribution and seasonal changes of C/N value and N/P value depended on change of total nitrogen to a great extent. Vertical distribution and seasonal changes of total potassium, calcium and magnesium presented some indefinite characteristics with certain random, which can not be looked as widespread still in mangrove area because of the lack of available data at present. Vertical identity between salinity and total sodium in mangrove soil owed to their same main source-seawate更多还原