Influence Of Environmental Changes On Stoichiometric Traits Of Nitrogen And Phosphorus For Larix Gmelinii Trees

Larix gmelinii Rupr the dominant species of boreal forest in China has the characteristics of strong a ability, such as fast growth, short growth cycle, cold tolerance and its wide distribution. I this paper, the response and adaptation to environmental changes of nitrogen (N) and phosphotos (P) stoichiometry of Larix gmelinii, which is a dominant boreal tree in northeastern Chii. was studied via a provenance experiment. Seeds from six provenances with different graphical and climatic conditions were collected and planted at a homogenous site in the them boundary of the distribution range of this species for32years. The objectives wer)(1) examine variations in the concentrations of N and P in different organs among six provenances,(2) explore monthly dynamics in the concentrations, and (3) exp:correlations between N and P concentrations in different organs. The results showed signifint differences between the concentrations of N in the needles among the provenances, narey old branch (P<0.05), fine roots (diameter1-2mm, P＜0.01), and medium roots (diameter2-5mm, P＜0.05), with the concentrations ranging from21.1±1.0to24.2±1.0mg·g-1, from5.9±0.5to7.8±0.5mg·g-1, and from4.7±0.6to6.5±0.5mg·g-1, respectively. The concentr as of P in the needles on old branch (P＜0.05) and needles on young twig (P＜0.05) weresignificantly different among the six provenances, with the concentrations ranging from4.5±0.3mg·g-1to5.8±0.3mg·g-1and from4.5±0.4to6.5±0.6mg·g-1, respectively. The N/P in the roots, branches and needles showed significant differences among the provenances,with the results ranging from2.7±0.4-3.1±0.5,2.5±0.3-3.4±0.4,3.9±0.3-5.4±0.4,4.2±0.2-5.3±0.3;2.8±0.3-3.6±0.4(0-1mm root),2.6±0.2-3.1+0.3(1-2mm root)、2.5±0.3-3.1±0.5(2-5mm root),2.0±0.2-3.1±0.4(>5mm root). The monthly variations in concentrations of N and P in the needles and roots tended to decrease first and then in tase, while those in the twigs showed a trend of increasing-decreasing-increasing. The were significant correlations between N and P concentrations in branches, needles, fine roots and medium roots as well as the N concentrations among needles, twigs, branches and roots,results suggested it is the adaptation of Larix gmelinii trees to different environments in six provenances that lead to a genetic differentiation in their stoichiometric traits of N P. N contents in every organs incresed with the increasing of MAT of different prove ces because different environmental factors changed the physiological property of L gmelinii.