[Non-structural carbohydrates characteristics of different forest layers in monsoon broad-leaved evergreen forest in Pu'er, Yunnan Province, China]. / 云南普洱季风常绿阔叶林不同林层非结构性碳水化合物特征.

Based on cluster analysis of species vertical stratification, the variations in concentration, allocation and seasonal dynamics of non-structural carbohydrates were investigated in a monsoon broad-leaved evergreen forest in Pu'er, Yunnan Province. The results showed that the concentrations of soluble sugar (3.9%) and nonstructural carbohydrates (NSC, 13.3%) were the highest in the sub-canopy. In contrast, the sugar/starch (0.76) of understory was the lowest. There was no significant difference in starch content among three forest layers. For all forest stories, the soluble sugar was mainly allocated to leaves and the roots had more starch and NSC. The soluble sugar contents in leaves and trunks of sub-canopy species were higher than canopy and understory species. There were no significant differences in soluble sugar content of twigs and roots among three different forest layers. The starch content of leaves increased with decreasing height of forest layers. In contrast, the lowest starch content (10.7%) of roots was in understory. There was no significant difference in starch content of twigs and trunks among three different forest layers. The NSC content of leaves was lower in canopy (10.7%) than that in sub-canopy (12.3%) and understory (12.0%). The lowest NSC content of roots was in understory (14.2%). The lowest sugar/starch of leaves, twigs, and trunks presented in understory, while the lowest sugar/starch of roots presented in canopy (0.79). There were dramatic seasonal variations in concentrations and components of NSC. The concentration of soluble sugar and the sugar/starch were higher in the rainy season than that in the dry season. However, the concentration of starch and NSC were higher in the dry season than in the rainy season. The variations in concentration of NSC and its components among forest layers indicated that species with different heights varied in their utilization strategies of carbon, which partly explained species coexistence.

[Species-area relationship at different succession stages of monsoon evergreen broad-leaved forest in south subtropical area of Yunnan Province].

Based on the investigation data of monsoon evergreen broad-leaved forest at its different succession stages (primary, CP; 15 years of succession, CF; and 30 years of succession, CT) in Pu' er of Yunnan Province, this paper studied the species-area relationship of this forest at each succession stage. It was found that in the communities at each succession stage, the number of total species, trees, shrubs, and lianas had a significant correlation with sampling area, with the area explained over 94% of the total variation. The Z value of the total species (0.334) and trees (0.394) was the lowest at CT, whereas that of shrubs (0.437) and lianas (0.326) was the lowest at CF. No significant differences were observed in the intercepts of the species-area curve of total species, trees, shrubs, and lianas among different succession stages, but the coefficient of determination (R2) of the species-area curve of total species and lianas was the highest at CP. The richness of trees and shrubs at CF explained 99.9% of the variance of Z value, but the richness of total species, trees, shrubs, and lianas at CP and CT had no significant correlations with the Z value.