【摘要】 本文对云南泸沽湖周边山地不同植被类型下采集的32个表土样品和36个泸沽湖湖泊表层样品进行了孢粉分析,探讨了不同植被类型内的表土孢粉散布特征,对比分析了山地表土与湖泊表层孢粉分布特征的差异。结果表明,不同山地植被类型的孢粉组合具有不同的代表性成分与变化特征,能够较好地反映相应的植被类型。湖泊表层孢粉研究表明,湖泊内不同位置的孢粉组合差异较小,说明湖泊表层孢粉反映的是区域植被的平均分布状况。对比分析泸沽湖周边山地表土与湖泊表层样品的孢粉组合,两者存在一定的差异,表现为:湖泊表层的孢粉组合中乔木花粉(主要是松属)平均含量比表土高,但波动范围要小;草本花粉平均含量要低,且波动范围也小。这可能是由于乔木植物植株较高,而且有些乔木植物花粉具有气囊,更易借助风力将花粉传播到比较远的湖泊中的原因造成的。冷杉和铁杉花粉在所有样品中含量都相对较低,分别不高于6.5%和3.6%;桦属、桤木属、常绿栎类花粉的最高值出现在有这些母体植物生长的表土样品中,在其他样品中则明显较低。在表土孢粉样品中经常可以见到冷杉的气孔器,但在湖泊表层样品中却没有见到,说明气孔器不易到达湖泊中。该研究是对中国西南表层孢粉研究的有益补充,同时为泸沽湖新生代特别是第四纪化石孢粉解释提供了可靠的参考和依据。更多还原

【Abstract】 Based on pollen analysis of 32 surface soil samples from different vegetation types in the mountains around the Lugu lake Yunnan Province,Southwest China and 36 surface lake sediments from the Lugu lake,the distribution characteristics of modern pollen rain from different vegetation types was discussed,and the differences of modern pollen assemblages between lake sediments and surface soils were compared.The results show that there are different representative components and variation characteristics in modern pollen assemblages from different vegetation types,which can reflect the corresponding vegetation types.The modern pollen rain of lake sediments suggests that the differences in pollen assemblages from different regions of the Lugu lake are relatively small,which indicates that surface pollen assemblage of lake sediments reflects an average distribution statue of the regional vegetation.Some differences exist between the pollen assemblages of surface soils and surface lake sediments.Average tree pollen percentages(mainly Pinus)in the pollen assemblages of surface lake sediments are higher than that in surface soils with relatively small fluctuant ranges,while herb pollen percentages in the pollen assemblages of surface lake sediments are lower than that in surface soils with relatively small fluctuant ranges.The possible reason is that tree plants can spread their pollen to lakes further depending on wind power because tree plants are higher than herbs.Abies and Tsugapollen percentages are relatively low among all samples,and less than 6.5%and 3.6%respectively.The maximum values of Betula,Alnus and evergreen oak pollen percentages are present in the surface soils with their parent plants growing nearby,while they are markedly lower in other samples.Abies stomata can be often found in surface soils,but it was not seen in surface lake sediments,suggesting that Abies stoma is not easy to spread to lake.This study is not only a useful supplement to the studies on modern pollen rain in the southwestern China,but also provides reliable reference and basis for the explanation of fossil pollen from the Lugu lake.更多还原