蓟运河故道消落带盐碱地土壤种子库特征

通过对蓟运河故道消落带的土壤种子进行萌发实验,确定了土壤种子库的物种组成、物种多样性指数和相似性指数,并对土壤种了库的物种特征进行了空间层次分析.结果表明:(1)蓟运河故道消落带土壤种子库共有16种植物,隶属于8科15属,其中藜科4种,菊科5种.3个区域土壤种子库物种相对多度和密度大小分布顺序为:洪淹区＞偶淹区＞常淹区.(2)不同区域种子库的Shannon—Wiener指数和Margalef丰富度指数随着水位的降低呈下降趋势,而生态优势度和Pielou均匀度指数有增大趋势.(3)种子库的空间分布特征明显,其中0--5 cm层种子数量最多,为623粒/m2；同时3个区域种子数量差异显著,洪淹区土壤种子库物种数量比偶淹区和常淹区分别多出253和353粒/,n2,而偶淹区土壤种子库物种数量与常淹区仅相差100粒/m2.

Characteristics of Soil Seed Banks in Saline Land of Hydro-fluctuation Belt Along Old Channel of Jiyun River

Seed germination experiments were conducted on the soils collected in the hydro-fluctuation beltalong the old channel of Jiyun River.The soil seed bank composition,species diversity,and their similarityand spatial distribution were discussed.Overall,16species including 4species of chenopodiaceae and 5species of asteraceae,belonging to 8families and 15genera,were identified in the soils.Species relative abundance and density distribution of the soil seed bank differed in topographic positions,in a descending order asheavily flooded area>incidentally flooded area>frequently flooded area.The Shannon-Wiener index andthe Margalef Richness Index decreased with water levels,while ecological dominance and Pielou evenness index showed an opposite trend.The seed bank also varied spatially.The 0-5cm layer was the richest in allthree areas in terms of seed number,with a quantity of 623per m².Meanwhile,the seed numbers differedsignificantly in the three areas;the seed number of heavily flooded area was 253and 353per m² more thanthat of the incidentally flooded area and frequently flooded area.