The Functional Traits Of Different Organs Of Pinus Tabulaeformis And Their Response To The Environment

There have been many studies on the relationship between leaf functional traits and environment, but most of them use the single or mean value of the traits to represent one species, ignoring the great intraspecific variations. In addition, the previous studies focused primarily on aboveground parts, and considered the underground parts or the relationship between functional traits of different organs, which restrict us to understand the life-history strategies of plants and their adaptation mechanism to the environment comprehensively. Pinus tabulaeformis is one of the main afforestation tree species in China, playing an important role in terrestrial ecosystem. Thus, research on the relationship between the leaf functional traits of P. tabulaeformis and environment factors could help us to know the relationship between intraspecific variations and environment. In this paper, we conduct an in-depth study on the distribution characteristics of roots, shoots and leaves functional traits, interrelation between them and their response to the environment, and the samples collected in Inner Mongolia, Liaoning, Beijing, Shanxi, Shaanxi, Ningxia and Qinghai Provinces, from June to September 2014. The results showed that:(1) The distribution characteristics and its controlling factors of the leaf functional traits of natural P. tabulaeformis.The leaf functional traits of P. tabulaeformis had significant intraspecific variation, and the variation coefficient is between 4.82% to 25.85%. The leaf length (LL), leaf thickness (LT), specific leaf area (SLA), stomatal density (SD), leaf nitrogen content (LNC) of the P. tabulaeformis exhibited a weak longitude distribution pattern and the LT, SD, LNC exhibited a weak latitude distribution pattern (0.05< R2<0.3). The combined effect of changing hydrothermal conditions along longitude and latitude and strong local effect might contribute to the formation of these patterns.Each leaf trait of P. tabulaeformis was affected by several factors, and the main controlling factors of different traits are different. In this study, we found that LL was mainly affected by mean annual precipitation and altitude; LT was mainly affected by mean annual temperature and volumetric soil water content; SLA was mainly affected by mean annual precipitation and soil nitrogen content; the leaf dry matter content (LDMC) was mainly affected by water factors; SD was mainly affected by altitude; LNC was mainly affected by altitude and water factors; the leaf phosphorus content (LPC) was mainly affected by soil phosphorus content.(2) The Nitrogen and Phosphorus Stoichiometry for different organs of p. tabulaeformis.Overall, the content of N and P in different organs is leaf (1.19% & 0.105%)> branches (0.75% & 0.091%)> root (0.65% & 0.025%). In addition, the N and P content of the measured leaves of Pinus tabulaeformis is significantly lower than that of national and global levels. The N content in different organs has a significant positive correlation with latitude, and a negative correlation with precipitation, and only the N and P content in root has a significant positive correlation with the temperature. There is a significant positive correlation between the N and P content in each organ except the root of third or more stage, but compared to the larger scale studies, the impact of the climatic conditions is quite significant. The content of N and P in different organs of P. tabulaeformis presents obvious coordinated variation trends, which is more obvious in new organs.