Abstract: Broad-leaved Korean pine (Pinus koraiensis) forest, a typical zonal vegetation in northeast China, harbors high biodiversity and is an important ecological resource. This study focused on the distribution of soil exchangeable cations Ca, Mg, K and Na, effective cation exchange capacity (ECEC), and exchangeable acidity as well as its main driving factors in the humic layer of the broad-leaved Korean pine distribution zone across nine degree of latitudes in northeast China. Results showed that the humic layer soils were biologically enriched with basal elements. The concentrations of soil exchangeable cations and ECEC had no obvious latitudinal variation. The concentration of exchangeable Mg and K were related with mean annual temperature or mean annual precipitation. Soil organic matter and pH were the two driving factors with positive effects on the distributions of base cations and ECEC. Soil exchangeable acidity was negatively correlated with ECEC and pH.

Key words: endogenous hormone., root morphology, drought stress, sweet potato, chlorophyll fluorescence parameter