【摘要】 对青藏高原黄河源区不同退化程度高寒草地的土壤种子库土样用土壤分析筛进行浓缩,并以萌发法分析土壤种子库萌发种子数量和动态.结果表明,孔径0.25~2 mm的土壤分析筛分离土样中萌发种子可达萌发种子总量的85%~97%,而小于0.25 mm的土样中未发现种子.因此,用0.25 mm孔径大小的土壤筛对高寒草地土壤种子库土样进行大规模浓缩是一种方便、可靠的方法.4种不同退化程度高寒草地(A:未退化草甸;B:轻度退化草甸;C:中度退化草甸;D:重度退化草甸)的土壤种子库在实验室条件下萌发的种子数量分别为:A 1 194~3 744粒/m2,平均2 421.3粒/m2;B 5 376~1 0912粒/m2,平均7 786.7粒/m2;C 2 304~1 3216粒/m2,平均8 695.5粒/m2;D 4 768~12 352粒/m2,平均8 125.9粒/m2.除样地A外,其它3个样地的可萌发种子数量差异不大.单子叶植物种子在培养到d 10左右开始萌发,双子叶植物在5~7 d内开始萌发,前者3 wk后基本不再萌发,后者5 wk左右停止萌发.4个样地土壤种子库种子萌发主要集中在第2~3周,并表现出近似单峰型格局.图1表3参39更多还原

【Abstract】 Soil seed banks of differently degraded meadows in the headwater region of the Yellow River in the Qinghai-Tibetan Plateau were studied by soil sifters and seed germination method at room temperature.The results showed that the soil sieves with mesh between 0.25 mm and 2 mm could separate 85%⁹7% seeds in the soil seed bank.No seeds could be found using sieves with mesh lower than 0.25 mm.The Mesh between 0.25 mm and 2 mm was used for this experiment.The（amounts） of germinated seeds in the soil bank of four different meadows（A: normal meadow;B: lightly degraded meadow: C: medium degraded meadow and D: heavily degraded meadow） under the laboratory conditions were showed: A 1 194³ 744 seeds/m² and 2 421.3 seeds/m² at average;B 5 376¹0 912 seeds/m²,7 786.7 seeds/m²;C 2 304¹ 3216 seeds/m²,（8 695.5） seeds/m² and D 4 768¹2 352 seeds/m²,8 125.9 seeds/m²,respectively.Except A,the germinating numbers of the other three were not significantly different.The seeds of moncotyledon plants began to germinate after culture for about 10 days and stopped germinating about three weeks later.The seeds of dicotyledon plants germinated within 5⁷ days’ culture and stopped germinating about five weeks later.The amount of seedlings was stable when germination ceased.All the seeds in the four plots mainly germinated in the period of 2³ weeks,and their germinating patterns were all unimodal curve.Fig 1,（Tab 3）,Ref 39更多还原