| 题名 | 古尔班通古特沙漠生物结皮中藻类物种多样性与生态学研究 |
| 作者 | 张丙昌 |
| 学位类别 | 博士 |
| 答辩日期 | 2009 |
| 授予单位 | 中国科学院．新疆生态与地理研究所 |
| 导师 | 张元明，中国科学院新疆生态与地理研究所 |
| 关键词 | 藻类 |
| 其他题名 | Species diversity and ecology of microalgaae in biological soil crusts in Gurbantunggut Desert |
| 中文摘要 | 文中以古尔班通古特沙漠生物结皮中的藻类植物为研究对象，通过野外调查、采样、实验室培养、显微观察、物种纯化、实验室测试和理论分析相结合的方法，对该沙漠生物结皮中藻类植物的区系特征、时空分布格局、演替规律以及高等植物对藻类分布的影响、生理培养进行了研究。本研究将为藻类在生物结皮中的人工应用提供理论依据，在新疆特殊的干旱环境下利用生物结皮进行防风固沙具有重要的实践意义。通过对该沙漠生物结皮中藻类区系和种类组成的研究结果发现，研究区有藻类植物120种，隶属4门25科52属，其中蓝藻87种，绿藻14种，硅藻11种，裸藻8种。研究区藻类的优势科/属均是丝状蓝藻，是生物结皮中的优势类群，寡种科/属和单种科/属占有很大比例，反映了研究区藻类区系的复杂性。典型沙垄的不同地貌部位和垂直层次对藻类的物种丰富度、种类组成和生物量均有一定的影响。藻类物种丰富度由垄顶至垄间低地逐渐升高；在垂直层次上则由表及里逐渐降低；藻类优势物种主要集中分布在0-2cm土层中，在0-0.5cm土层中第一优势种多为具鞘微鞘藻；藻类最常见的物种有铜绿蓝杆藻、小聚球藻、大型集胞藻、土生绿球藻、脆杆藻1和双尖菱板藻等，同时在不同地貌部位和垂直层次中存在一些特有种；藻类生物量在垄间低地最高，迎风坡与背风坡居中，垄顶最低，在沙垄垂直层次上由表及里急剧降低。除垄顶外，藻类生物量均有明显的季节变化，表现为春季生物量最高，夏季次之，秋季最低；同时，季节对同一地貌部位中藻类种类组成亦有一定的影响。生物结皮的不同演替阶段对土壤理化特性、种类组成和生物量均有一定的影响。生物结皮不同的演替阶段对土壤有机C、全N、速效N影响显著（P<0.05），但对全P、速效P、全K、速效K影响不显著；藻类的种类组成在不同演替阶段发生一定的变化，裸沙、藻结皮、地衣结皮和苔藓结皮的优势种分别是脆杆藻1、具鞘微鞘藻、眼点伪枝藻或集球藻，其中具鞘微鞘藻在藻结皮、地衣结皮两个演替阶段均有出现；生物结皮不同演替阶段对藻类生物量影响显著，在裸沙中藻类生物量最低，随着生物结皮的逐渐发育，藻类生物量明显升高，在地衣结皮中达到最高；土壤理化特性、藻类种类组成和生物量之间存在一定的互馈作用；丝状藻类在生物结皮的演替过程中逐渐占明显的优势（尤其是具鞘微鞘藻），另外真菌菌丝和苔藓假根分别在地衣结皮和苔藓结皮中起着重要作用。在古尔班通古特沙漠生物结皮中，藓类植物物种多样性低，其中占优势的藓类植物是齿肋赤藓，此外还有泛生墙藓无芒变种、绿色流苏藓、真藓和柔叶真藓；除以真藓为优势的藓类结皮中藻类优势物种是眼点伪枝藻和念珠藻，其它几种藓类为优势的结皮藻类优势种均是具鞘微鞘藻；在其它几种藓类结皮中，眼点伪枝藻、拟短形颤藻、念珠藻、集球藻和土生绿球藻也是最常见的物种。具鞘微鞘藻和齿肋赤藓之间存在一种互利共生的关系，适当浓度的齿肋赤藓提取物能有效地促进具鞘微鞘藻的生长，具鞘微鞘藻提取液对齿肋赤藓的萌发、生长亦有一定的促进作用。蛇麻黄和沙蒿植丛对藻类物种多样性、种类组成和群落结构均有一定的影响。如具鞘微鞘藻在两种植物覆盖的表层土壤中均为优势物种，但随着与蛇麻黄或沙蒿植丛距离的增大，其优势度逐渐增大；蓝藻和丝状藻类的优势度由植丛内至植丛外有明显的上升，而绿藻、硅藻、单细胞和球形种类的优势度则呈明显的下降趋势，这可能是由光照强度、紫外线、温度和土壤水分等多种因素综合影响所致。通过对几种典型蓝藻的生理培养表明，K+、Ca2+、Mg2+和pH对于不同物种的影响不同，同时确定了具鞘微鞘藻、眼点伪枝藻、念珠藻的最适培养条件。Biological soil crusts (BSCs), most notably lichen crusts, develop and diversify in the Gurbantunggut desert, the largest and semi-fixed desert in China. Focused on the pioneer component (microalgae) in BSCs, we conducted to flora characteristic, ecological distribution, succession, and interspecfic relationship of microalgae by using field investigation, sampling, lab incubation, micro-observation, purification and separation, lab test and statistic analysis. The results would be helpful to better understand the mechanism of BSCs and their function on desertification control, and it should contribute to further study on the growth and development of artificial BSCs. The main results were as followings: In BSCs of the Gurbantunggut Desert, 120 taxa, belonging to 52 genus, 25 families and 4 divisions, were found. Four divisions are cyanophytes, chlorophytes, diatoms and euglenoids, in which 87 species are cyanophytes, 14 species are chlorophytes, 11 species are diatoms and 8 species are euglenoids. Document families or genus were filamentous cyanobacteria, which were document communities in BSCs. Some families or genus, only containing few or single taxa, account for a large proportion in the flora of the study areas, which indicates complexity of microalgal flora. In the typical sand dunes, different sand locations and soil layers with different depth had effects on species diversity, species composition and biomass of microalgae. Species diversity of microalgae was increased from the top of sand dunes to the interdune areas of sand dunes whereas decreased from the surface to the deeper layers. Microalgal dominant species mainly focused on 0-2 cm layer. In most case, the 0-0.5 cm layer was dominated by Microcoleus vaginatus. In different sand locations, the most common species were Cyanothece aeruginosa, Synechococcus parvus, Synechocystis crassa, Microcoleus vaginatus, Chlorococcum humicola, Fragilaria sp.1, and Hantzschia amphioxys. Additionally, some species were rare, they only appeared in a single layer in some sand location. Microalgal biomass was significantly affected by locations of sand dunes and soil layers with different depth. Microalgal biomass was highest in inter-dune areas, followed by the windward and leeward of sand dunes, and lowest in the top of sand dunes. In spite of the top of sand dunes, microalgal biomass in other sand locations was obviously influenced by seasons, which represented by the highest in spring, followed by summer, and the lowest in autumn. Different successional stages of BSCs significantly affected the content of soil organic C, total and available N, but not the total and available P and K content of soil. Composition of microalgal communities differed among the four successional stages. Dominant species in bare sand, microalgal crusts, lichen crusts, and moss crusts were represented by Fragilaria sp.1, M. vaginatus and Scytonema ocellatum or Palmellococcus miniatus. M. vaginatus was the same dominant species in algal and lichen crusts. Some species were specific of the successional stage. Significant differences in microalgal biomass were observed among the four successional stages. Microalgal biomass was the lowest in bare sand, increased with BSCs development and reached the highest value in lichen crusts. Some interaction existed among soil physiochemical properties, microalgal composition and biomass. Bare sand was mainly uncompacted sand gains. Filamentous cyanobacteria, particularly M. vaginatus, were the dominant species in the early phase of crust succession. The presence of fungal mycelium and moss rhizoids prevented water and wind erosion. Bryophyte diversity in BSCs of the Gurbantunggut Desert was low, which was mainly composed of Syntrichia caninervis, Tortula muralis var. aestiva, Crossidium squamiferum, Bryum argenteum, and Bryum cellulare. In moss crusts dominated by Bryum argenteum, dominant species of microalgae were Scytonema ocellatum and Nostoc sp.. And the other moss crusts were dominated by M. vaginatus. The most common species in moss crusts were S. ocellatum, Oscillatoria subbrevis, Nostoc sp., Palmellococcus miniatus, and Chlorococcum humicola, which were sub-dominant species. There exists a symbiotic relationship between M. vaginatus and S. caninervis. Suitable concentration extracts of S. caninervis may facilitate the growth of M. vaginatus, on the other hand, the extracts of M. vaginatus can promote the germination and growth of S. caninervis. Species diversity, species composition and community structure were showed some change in the areas of Ephedra distachya and Artemisia arenaria. In the surface soil layer of shrubs, the dominant species of microalgae was M. vaginatus. However, the dominant degree of M. vaginatus increased gradually away from the shrubs. From inward shrubs to outward shrubs, the dominant degree of cyanobacteria and filamentous microalgae increased clearly, whereas that of green microalgae, diatom, unicellular and coccoid species showed a decreasing trend, possibly due to integrative effects of light intensity, ultraviolet radiation, temperature and soil moisture. Physiological cultivation of several cyanobacteria indicated that K+, Ca2+, Mg2+ and pH may have different effects for different species. The author explored and advanced the optimal conditions of cultivating M. vaginatus, S. ocellatum and Nostoc sp. |
| 语种 | 中文 |
| 学科主题 | 微生物学 |
| 公开日期 | 2010-11-12 |
| 页码 | 共120页 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.xjlas.org/handle/365004/8446]  |
| 专题 | 新疆生态与地理研究所_中国科学院新疆生态与地理研究所(2010年以前数据) |
| 推荐引用方式 GB/T 7714 | 张丙昌. 古尔班通古特沙漠生物结皮中藻类物种多样性与生态学研究[D]. 中国科学院．新疆生态与地理研究所. 2009. |
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