Effects Of Environmental Factors And Phylogenesis On Plant Functional Traits In Tropical Cloud Forests

Tropical cloud forest is one of the most intact forest types in the tropics.Compared with the low altitude tropical forest, it is rich in plant diversity and the environmental conditions are very special. The characteristics of plant functional traits and the way to adapt to the environment may be different from the low altitude tropical forest. In this paper, we aimed to investigated plant species composition and measured plant functional traits in Bawangling, Limushan and Jianfengling of the tropical cloud forest. In addition, we need to analyze the information of DNA fragments(rbcL?matK?trnH-psbA?ITS) in different forest areas and determination of environmental factors. Finally, we will to construct the phylogenetic tree of plant species, and to explore the variation of plant functional traits on the community organization levels and system taxonomic levels. More importantly, we will also study the effects of environmental factors and phylogenetic relationships on the variation of plant functional traits in tropical cloud forest.1) Overall, results showed that the success rates of PCR amplification of rbcL,matK,trnH-psbA and ITS were 75.26%±4%,57.24%±4%, 79.28%±7%,50.31%±7%, and the rates of DNA sequencing were 63.84%±4%,50.82%±4%, 72.87%±11%,45.15% ±9% respectively Bawangling,Limushan and Jianfengling. And the four selected fragments have good universality. Applying BLAST method to statistic success rate of species level, ITS had the highest success rate of identification(47.20±6%), followed by trnH-psbA(46.16%±5%) and matK(42.88%±3%), the lowest rbcL(41.50%±3%). Phylogenetic tree constructed by neighbor joining method(NJ). When the phylogenetic relationships were built with random fragment combinations, optimal evolutionary tree with high supporting values were established using the combinations of rbcL + matK + trnH-psbA in tropical cloud forests.2) The variation of plant functional traits at different community organization levels (individual, intraspecific, interspecific and community) in Bawangling,interspecific level> intraspecific level> individual level> community level.Interspecific and intraspecific level variation more greater than individual and community level in Limushan, Jianfengling. However, The variation of plant functional traits at different taxonomic levels (family, genera and species) in Bawangling, species level > family level>genera level. In Limushan, species level>genera level> family level. In addition, species level > family level>genera level in Jianfengling.3) In study, the principal component analysis showed that soil organic matter,available phosphorus and slope were the main environmental factors in Bawangling.In Limushan, total phosphorus, total nitrogen and available nitrogen were the main environmental factors. In the soil organic matter, total nitrogen and available nitrogen is the main environmental factor in Jianfengling. Multiple stepwise regression analysis of the relationship between environmental factors and plant functional traits,it was found that the effect of phosphorus on the variation plant functional traits was the largest in Bawangling. Soil nitrogen and phosphorus had different effects on the viariation of functional traits, but the effect of nitrogen is larger in Limushan. In Jianfengling,both soil organic matter and nitrogen have important effects on the variation of plant functional traits . And then, K value method was used to calculate the phylogenetic signal of plant functional traits of woody plants in three forest areas.The results showed that Leaf mass per area(LMA) detected significant phylogenetic signal in Limushan, In addition, the phylogenetic signal is close to significant of wood density(WD),soluble sugar of leaf(SC.L) in Limushan and Leaf mass per area(LMA)in Bawangling. The phylogenetically independent contrast (PIC) was used to deal with the 4 functional traits and need to analysis of the relationship between environmental factors and plant functional traits. It was found that the soil phosphorus had a significant effect on the functional traits in Limushan.