神农架北坡表土常见花粉的R值研究

根据表土孢粉分析和植被样方调查的比较研究，获得了神农架北坡表土常见花粉的R值，常绿阔叶树花粉一般具有较低代表性，R值变化于0．70左右，绝大部分落叶阔叶树花粉也具有较低代表性，R值变化于0．68－0．88之间，但桦，桤木和槭却表现异常，针叶树有气囊花粉具有明显的超代表性，R值变化在1．35－2．44之间，松表现最为强烈，草本植物花粉的R值变化较大，代表性较差，影响R值的因素很多，植物的生态特性，花粉特征，花粉源距离，花粉产量，地形等作用尤为明显。

A Study on the Representation of Common Pollens in Soils on the Northern Slope of Shennongjia Mountains

The representation of common pollens in soils on the northern slope of Shennongjia mountains area is studied in the light of sporo pollen analysis and plantation sample investigation. Most of broadleaved tree pollens such as Quercus, Ilex, Fagus, Juglans,Castanea, Carpinus, Corylus, Ulmus, Tilia and Salix , have a under representation except Betula and Alnus which have a suitable representation. Some main conifer tree pollens such as Pinus, Abies and Picea , have a over representation except Cupressaceae and Taxodiaceae which have a under represeatation. The research shows that the representation of pollen is influenced from pollen character, external pollens, pollen output, distance from pollen sources and landform.