【作者】 李琳；

【导师】 肖洪兴；

【作者基本信息】 东北师范大学 ， 植物学， 2014， 硕士

【摘要】 松嫩草原独特的生态功能和经济价值一直备受关注,近年来学者们对该区域内的高等植物群落进行了大量的研究,但对该区域广泛存在的低等植物蓝藻却没有给予必要的关注。本研究以松嫩草原地表广泛分布的藻结皮为研究对象,选取了羊草(Leymus chinensis)群落、星星草(Puccinellia tenuiflora)群落、虎尾草(Chloris virgata)群落、碱蒿(Artemisia anethifolia)群落、角碱蓬(Suaeda corniculata)群落地表以及天然碱斑地表生长的藻结皮。对划定样地地表分布的结皮进行了蓝藻种类组成鉴定、厚度及生物量测定。通过传统形态学方法对样地采集的原始样品及经过实验室培养后的藻结皮进行了初步制片观察,并运用现代分子生物学的方法探讨了不同植物群落下藻结皮中蓝藻的物种多样性。同时还对三种藻结皮进行了模拟氮降解过程实验。生态学的研究包括不同植物群落下藻结皮与下层土壤之间的关系,探讨了不同植物群落下藻结皮存在对下层土壤温度、土壤含水量、土壤pH、土壤电导率的影响。研究结果表明：具鞘微鞘藻(Microcoleus vaginatus)和普通念珠藻(Nostoc commune)在各样地藻结皮中均为优势种。不同植物群落下藻结皮厚度差异显著,生物量差异显著。藻结皮的存在可以在一定程度上降低土壤表层的温度,增加土壤表层含水量,降低表层土壤的pH和电导率。不同植物群落下的藻结皮在降解速率上存在差异,降解速率受藻结皮厚度和生物量影响。本研究对该区域藻结皮中蓝藻物种组成及其生态学研究是很好的补充,丰富了草原生态系统生物结皮的研究,对完善干旱、半干旱生态系统生物结皮的研究更具理论意义。更多还原

【Abstract】 The Songnen grassland always has special ecological position and important economic significance. Recently, the scientists did a lot of researches on the vascular vegetation existed in this region, but they paid less attention to the widespread cyanobacteria. The cyanobacteria also have more important ecological functions, which is one of the essential components of the algal crust in this area. We selected the elementary biological soil crusts that subordinate to northeast normal university as the experiment matter in this research. We chose5kinds of vegetation types and a natural alkali spot as the experiment plots:Leymus chinensis community, Puccinellia tenuiflora community, Chloris virgata community, Artemisia anethifolia community, Suaeda corniculata community and Alkali spots.The cyanbacteria species composition of algal crusts was identified with the traditional morphology and molecular methods, the thickness and biomass of the algal crusts in difference vegetation types were also determined, and at the same time the weight degradation and the nitrogen contents were surveyed. The ecological functions of the algal crusts was researched as follows:the relationship between algal crusts and underground soil, including the temperature, water content, pH value, electrical conductivity.The results showed that the Microcoleus vaginatus and Nostoc commune are the dominant species in algae crusts in every experiment plots. The differences of thickness and biomass are statistically significant. The soil temperature, pH value and electrical conductivity in algae crusts plot is lower than that without algae crusts. The soil water content with algae crusts plot is more than that without algae crusts plot, but the differences of them were not statistically significant. The difference of degradation of weight and nitrogen in three kinds of algal crusts were affected by many factors, such as thickness and biomass.This study is a good supplement in the cyanobectiria species composition and ecology to this area and the grassland ecosystem. It also will make a big contribution to the biological soil crusts in arid or semiarid ecosystem.更多还原