松嫩平原羊草草甸植物的生态及分布区型结构分析

松嫩平原羊草草甸穿越吉林省西部和黑龙江省西南部约129万hm^2的范围，是蒙古植物区系，东北植物区系，兴安植物区系，华北植物区系4个植物区系相汇集的区域，在全区所设的36个调查样地中，共有162个植物，隶属于36个科，6个株生长型，5个根生长型，6个生活型，5个水分生态类型，15个分布区型和6个经济价值类型。其中，菊科种类最多，占24．1％，豆科和禾本科分别占11．1％和10．5％；株生长型结构以分枝型种类最多，占31％，直立型和丛生型分别为22％和20％，根生长型结构以直根型的种类最多，占54％，刷状根型和根茎型分别为23％和19％；生活型结构以地面芽植物最多，占42％，地下芽植物次之，,占26％，地面－地下芽植物占9％，水分生态类型结构以中生型种类最多，占58％，中旱生型次之，占25％,分布区型结构以蒙古－东北－兴安－华北分布区型的种类最多，占26％，东北－华北分布区型次之，占17％，经济价值类型结构以中、低等质量的种类最多，所占比重高达50％，而优，良牧草种类只占22％，松嫩平原羊草草甸具有温带草本群落的植株和根系的特点，典型的温带地面芽植物气候特征，中生生境条件，复杂的分布区型结构和多样的经济价值类型。

Analysis on structures of ecological and areal types for plant species in Leymus chinensis meadow in the Songnen Plains of China

The Leymus chinensis meadow of the Songnen Plains ranges from the west of Jilin province to the southwest of Heilongjiang province. The area is about 1 290 000 ha and it is the influx of Mongolian flora, Northeastern flora, Dahuricia flora and Chinese north flora. Investigated 36 sample sites in this area, all the 162 species of plants belong to 36 families, 6 growth forms of plant, 5 growth forms of root, 6 life forms, 5 ecological types of water, 15 areal types and 6 economic value types. Among them, the species of Compositae take the most of 24.1%, and those of Leguminosae and Gramineae are 11.1% and 10.5%. The species of limb type are 31% of the growth form of plant, as well as those of endlong type and tuff type are 22% and 20%. About the growth form of root, the most species of 54% belong to taproot type, as well as 23% and 19% belong to brush root type and rhizome type. The life forms of most plants belong to hemicryptophyte which are 42% then geophyte are 26% and hemicrypto-geophyte are 9%. The species of mesophyte are the most of ecological type of water that take 58% and those of mesoxerophyte take 25%. The species of Mongolian-Northeastern-Dahuricia-Chinese north areal type are 26% of areal type and those of Northeastern-Chinese north areal type are 17%. In the economic value type structure, the species of middling and lowness quality take the most even 50%, but those of high and fine quality only take 22%. In conclusion, in the Leymus chinensis meadow of the Songnen Plains, the plants and roots take on the characters of temperate herbage community, climate is typical temperate hemicryptophyte, besides that, there have mesophitic habitat condition, complex structure of areal types and various economic value types.