Response of photosynthetic nitrogen use efficiency in Betula utilis to altitudinal variation along Balang Mountain, Sichuan, China.

To better understand the response and adaptation of plants to altitudinal changes, four sites at the altitude of 2200 m, 2500 m, 3100 m and 3400 m on Balang Mountain were selected to test and calculate the eco-physiological parameters in leaves of Betula utilis, including photosynthetic nitrogen use efficiency (PNUE), CO diffusion conductance (stomatal conductance g and mesophyll conductance g) and nitrogen allocation in each component (fractions of leaf nitrogen allocated to Rubisco P, to bioenergetics P, to light-harvesting components P, and to cell wall P). Their changes with altitudinal variations and the relationships between leaf PNUE and the other parameters were analyzed. The results showed that PNUE, P, and P of the leaves were relatively higher at 2500 m and 3100 m.

[Phenotypic variations in cones and seeds of natural Cupressus chengiana populations in China].

A total of 13 phenotypic traits from 11 natural populations of Cupressus chengiana were investigated by using nested analysis, variation coefficient, phenotypic traits differentiation coefficient, and un-weighted pair-group method by arithmetic averages (UPGMA) cluster analysis. Phenotypic variations among and within populations of C. chengiana were discussed, the relationship among phenotypic traits and that between phenotypic traits and environmental factors were analyzed, and the 11 populations were divided.

[Soil microbial community structure of monoculture and mixed plantation stands of native tree species in south subtropical China].

The effects of three plantation stands, Erythrophleumf ordii (EF), Pinus massoniana (PM), and their mixed plantation (MP), on soil microbial biomass and microbial community structure in south subtropical China were studied by the method of phospholipid fatty acids (PLFAs) analysis. The results showed that the amounts of microbial total PLFAs and PLFAs of each microbial group in these three plantation stand soils were significantly higher in dry season than in rainy season. In dry season, the amounts of microbial total PLFAs, bacteria PLFAs, fungi PLFAs, and actinomycetes PLFAs were the highest in the PM soil, moderate in the MP soil, and the lowest in the EF soil.