Heterogeneity in Soil Seed Banks in a Mediterranean Coastal Sand Dune

地中海沿岸沙丘土壤种子库的异质性(英文)

Characteristics of total soil seed banks and permanent soil seed banks in three microhabitats in a Mediterranean coastal sand dune were investigated by using natural germination method combined with physically scanning separation method. The composition and structure of soil seed banks were analyzed between the microhabitats by using functional group method. The distribution patterns of soil seed bank were also analyzed between the microhabitats. We also analyzed the relationship between seed size and seed persistence in soil. The results show greatly spatial heterogeneity existed in soil seed bank of the Mediterranean coastal sand dune, even in the same microhabitats seed distribution was uneven. Sometimes a great difference occurred between them. Microhabitats significantly affected the distribution patterns of total soil seed banks and seed banks of the functional groups. The open area generally had the greater densities of seeds, but the seed densities under shrub and in trail were lower than that in the open area. Legumes seeds accounted for 76.0% total persistent seed banks. Annual and perennial grasses produced transient seed banks as no seeds were retrieved from the sieved soils. Seed persistence of legumes, umbeliferaes, perennial forbs, compositaes, annual forbs, crucifer decreased gradually. They were 50.1%, 45.6%, 40.6%, 6.3%, 5.6% and 0.6% respectively in the soil. There was a positive relationship between seed size and seed persistence. Bigger seeds had higher persistence, and vice versa.

应用自然萌发法和物理筛选法相结合的方法 ,调查了地中海沿岸沙丘三种微生境土壤总种子库和永久种子库特征 ,用功能群的方法分析了微生境之间的土壤总种子库和永久土壤种子库的组成和结构差异 ,也分析了主要物种土壤种子库的微生境分布格局 ,分析了种子大小和土壤种子库中的种子永久性关系。发现地中海沿岸沙丘土壤种子库具有明显的空间异质性 ,即使在相同的微生境内 ,土壤种子库的分布也不是均匀的 ,甚至具有很大的差异 ;微生境对总的土壤种子库和各功能群的土壤种子库的分布格局具有显著的影响 ,开阔地区域具有最大的种子密度 ,而灌丛下和路径具有较小的种子密度 ;在永久土壤种子库中 ,豆科类植物种子在休眠种子中占有最大的比例 ,约为 76 % ,而一年生和多年生禾草未发现休眠种子 ,豆类、伞形科类、多年生阔草、菊科类、一年生阔叶草和十字花科类等种子在土壤中的永久性比例依次下降 ,分别为 5 0 %、4 6 %、4 1%、6 %、6 %和 1% ,微生境影响各功能群种子在土壤中的永久性。微生境显著影响大部分主要物种的土壤种子库分布 ;种子大小与其在土壤中的永久性为正相关 ,即大种子具有较高的永久性 。