科尔沁沙地围封沙质草甸土壤种子库特征的研究

Characteristics of the soil seed bank at the fenced sandy meadow in Horqin Sandy Land

科尔沁沙地沙质草甸围封 5年后土壤种子库中植物种类有 38种 ,其中一、二年生草本植物 2 4种 ,多年生草本植物 9种 ,灌木 5种。土壤种子库密度为 (1385 5± 16 5 1)粒·m-2 ,其中 ,一、二年生草本植物所占的比例最大为 96 5 8% ,前 5种一、二年生草本植物黄蒿、灰绿藜、猪毛菜、狗尾草和画眉草占总数的 87 2 0 % ,而多年生草本植物和灌木类种子库密度分别占0 94 %和 2 4 8%。若以单子叶和双子叶植物统计 ,单子叶植物种子数占 13 13% ,双子叶植物的种子数占 86 87% ,其中豆科植物仅占 2 83%。土壤种子库中所有植物种的密度与其相对应的地面植物种的密度呈显著非完全相关性 ,其关系可用三次曲线来表示。从种子库组成分析 ,已围封 5年的沙质草甸植被仍处在黄蒿 -杂类草混合植被阶段。

The soil seed bank of the sandy meadow after 5 years enclosure of was studied. The results showed that the number of plant species was 38, among which, that of annuals and biennials,that of perennials and that of brushes was 24,9 and 5,respectively. The overall density of the soil seed bank was 13855±1651 grains·m -2 ,among which, that of annuals and biennials was 96.58% of all the grains,87.20% was the annuol and biennial seeds of Artemisia scoparia,Chenopodium glaucum,Salsola collina,Setaria viridis and Eragrostis pilosa. Only 0.94% and 2.48% of the grains were those of perennials and brushes respectively. If divided into monocotyledoneae and dicotyledoneae, the number of seeds of the former accounted for 13.13% of that of total seeds while that of the later constituted 86.87%. The Leguminecae species comprised 2.83%. Regression indicated that the relationship between density of the soil seed bank and that of associated vegetation could be described by a cubic curve. The fenced sandy meadow vegetation would be in the stage of mixture of A. scoparia. et and forbs.