大兴安岭北部兴安落叶松种子在土壤中的分布及其种子库的持续性

THE DISTRIBUTION OF SEEDS IN THE SOIL AND THE SUSTAINABILITY OF THE SEED BANK OF LARIX GMELINI IN NORTHERN DAXINGANLING MOUNTAINS

种子年后原始老龄林下自然散布的兴安落叶松土壤种子极为丰富。有生活力的土壤种子数量为１９０～３２０粒／ｍ２，并且不同林型间有显著差异。７０％～８０％的种子主要居于土壤表层２～４ｃｍ范围内。落叶松老龄林种子年后第一年夏季土壤中丰富的种子即锐减，土壤中大多数种子的生活力保持１年，少数稍长，也不超过２年。显然，落叶松土壤种子库属于间断类型。人工撒播种子试验结果表明，位于土壤浅层（０～１０ｃｍ）的种子生活力保存只１年，而深层（１０～２０ｃｍ）尽管对种子生活力保持有利，也不能超过２年。土壤病害是种子致死的重要原因。

There were rich seeds of Larix gmelini dispersing naturally in the soil of old-growth larch stands after a mast year. Vital seeds in the soil amounted to 190～320 grains/m2, showing a significant difference among different forest types. Seeds existing in the upper layer of the soil within a scale of 2～4cm accounted for 70%～80% of the total amount. The vitality for most seeds that could germinate rapidly under optimal conditions would last no more than one year, seldom over two years. It was quite evident that the seed bank of Larix gmelini in the soil was of the interrupted type. Meanwhile, by a test of sowing seeds artificially, we got a result the same as above. The pathogens in the soil was the main reason causing death to seeds.