亚气生蓝藻在草原生态系统中的作用

【作者】 范亚军；

【导师】 肖洪兴；

【作者基本信息】 东北师范大学 ， 植物学， 2004， 硕士

【摘要】 本文研究了东北草原样地中亚气生蓝藻的组成与分布，并对藻结皮与相关环境因子的关系进行了探讨与分析。在2002~2003年两个生长季内采集了蓝藻标本，并设立了四块实验样地，每块样地两次重复。经初步鉴定草原区共有亚气生蓝藻31种，隶属于4科9属。在不同群落样地中亚气生蓝藻的优势种不同。扫描电镜观察藻结皮结构证明藻结皮具有一定的层次，丝状体蓝藻结成绳状或网状直接与土壤颗粒接触，位于藻结皮底层，这些丝状体蓝藻主要为沼地微鞘藻（Microcoleus paludosus Kütz .）Gom.）、具鞘微鞘藻（M. vaginatus (Vauch .) Gom）、爪哇伪枝藻（Scytonema javanicum (Kütz.) Born）、马氏鞘丝藻（Lyngbya martensiana Menegh. et Gomont ）。而原植体为球形或原植体在生长后期变为膜状的蓝藻则位于结皮上层，主要种类为普通念珠藻（Nostoc commune Vauch）、灰色念珠藻（N. muscorum Ag. ）、棕黄粘杆藻（Gloeothece fusco-lutea N?g .）。研究表明藻结皮在草原生态系统中具有一定的生态作用。藻结皮对土壤含水量有一定影响，同种群落样地中有藻结皮土壤含水量高于去藻结皮土壤含水量，主要由于蓝藻具有较厚的胶鞘或胶被，一方面能够吸收并储存水分，另一方面随着温度升高和降雨量的增多，藻类生长迅速，藻结皮不断加厚，能够起到防止地表土壤水分蒸发的作用。藻结皮对土壤含氮量也有一定的影响，同种群落类型样地中有藻结皮地表土壤含氮量高于去藻结皮地表土壤含氮量，这是因为有些蓝藻种类能够固氮并将一部分氮素释放到土壤中，而且藻类植物体自身降解也可增加土壤有机质，提高土壤肥力。不同群落类型中藻结皮的降解速率有差异，这种差异主要是由藻结皮厚度和组成藻结皮的藻类种类决定。更多还原

【Abstract】 The species and distribution of subaerial bule-green algae in northeast grassland are researched in this paper, the relation between the algal crust and the environmental factors is also discussed and analysed. During the growth season in the year 2002~2003, I selected 4 different research sites, every site was repeated. There are 31 species subaerial blue-green algae which subordinated to 3 families, 9 genus are founded, there are different superior species in different communities. It is verified that the algal crust has certain structure through using the scaning electron microscope. The filiment algae interwined rope-like bundles or nets among the soil particles, they live in the lowest layer of algal crust . These main species are M. paludosus 、M. vaginatus、S. javanicum 、L. martensiana. The spherical thallus live in the up-layer of the crust .The main species are N. commune、N. muscorum、G. fusco-lutea .Consequently express the algal crust in the grassland ecosystem has certain ecological effects . The algal crust affect the moisture content . In the same research site , the moisture content of soil is higher than that without algal crust . The main reason is that the blue-green algae have thick sheath , the sheath can absorb more water, and the higher temperature and more rain thicken the algal crust . they help to maintain moisture in the soil .The algal crust also affect the nitrogen content of the soil . In the same research site the nitrogen content of the soil with algal crust higher than that non-crust . It is because that some species of blue-green algae can fix nitrogen and release some of it in the soil. The degradation of the thallus increase the organic matter of soil and fertilize the soil . The degradation rate of algal crust in every community is different , the difference mainly due to the thickness of algal crust and species of the blue-green algae.更多还原