消落带湿地土壤苍耳种子库研究

Soil Seed Bank of Xanthum sibircum in Newly Created Wetlands in Water-Level Fluctuation Zone of Three Gorges Reservoir

为了解三峡水库三期蓄水后消落带新生湿地苍耳种子库,于2010年4月对澎溪河消落带湿地进行了调查.结果表明：（1）土壤表层（0~5 cm）种子密度、萌发率及萌发数量均随海拔升高而增加.（2）种子密度介于490.33~1 191.83颗/m2之间,萌发率从0.20%到18.45%,萌发数量为1~214颗/m2.（3）多重比较检验显示,无论植物群落类型还是水位梯度上种子密度、萌发率和萌发数量差异均不显著（p〉0.05）.（4）相关分析表明,萌发率、萌发数量与群落类型显著相关（p〈0.05）,种子密度与植物群落类型极相关（p〈0.01）;萌发数量与水位梯度相关性极显著（p〈0.01）,但萌发率、种子密度与其不相关（p〉0.05）.三峡水库水位周期性变动下,苍耳种子空间分布格局发生改变,种子在消落带范围内的分布趋于均质,同时由于微生境的异质性而产生一些差异.

In April 2010,an investigation was made to study the X.sibircum dynamics of soil seed bank in water-level fluctuation zone of the newly created wetlands-Three Gorges Reservoir after flooding to 173 m height.The following results have been obtained：（1）The germination rate,germination amount and the seed density in soil surface（0~5 cm）increased with altitude.（2）The density ranged from 490.11 to 1 191.83 grain/m2,while the germination rate went from 0.20% to 18.45% and germination amount was between 1 to 214 grain/m2.（3）LSD analysis showed that the seed density,the germination rate and the quantity of germination are of little difference（p0.05） neither on community types nor water-level fluctuation gradient.（4）Correlation analysis indicated that the relationships among community types,germination rate and quantity of germination were significant correlation（p0.05）,while seed density was highly significant correlation（p0.01）.The relationship between the amount of germination and water-level fluctuation gradient was highly significant correlation（p0.01）,but the germination rate and seed density weren＇t（p0.05）.The spatial distribution pattern of X.sibircum seed was changed to accommodate the cyclic change of water-level fluctuation in Three Gorges Reservoir.The distribution of seeds in the range of the littoral zone tends to become homogeneous,and because of microhabitat heterogeneity they show some differences.