本项目拟在华北地区管涔山、小五台山和内蒙古南部克什克腾世界地质公园选择多个研究样区，以白扦为研究对象，沿水热条件变化水平梯度和垂直梯度带，研究其年轮形成中木质部生长与非结构性碳水化合物的相互影响关系。项目将以植物组织切片、非结构性碳水化合物含量和组分分析、环境要素原位观测等技术方法，检测随着木质部生长变化过程，非结构性碳水化合物在白扦不同器官和组织中的分配格局及其动态变化。本项研究旨在回答以下主要科学问题：（1）“源”器官中的非结构性碳水化合物含量是否与木质部生长过程相关，以及木质部生长不同阶段中，哪个阶段是非结构性碳水化合物转化为结构性生长的主要阶段？（2）非结构性碳水化合物含量对环境要素变化和生长过程变化响应的各自特征是什么？（3）与碳平衡机制相关的生长受限是否发生？在何种条件下、哪个生长阶段发生？

This study aims at revealing the interactive relationship between the intra-annual xylem growth and the non-structural carbohydrate contents within tree tissues of Picea meyeri in its tree-ring formation process. The study will choose the Guancen Mountains, the Xiaowutai Mountains and the Hexigten World Geopark as sampling sites, to form two transects of hydro-thermal gradients, one laid out from Central-North China to South Inner Mongolia as a south-north horizontal transect and the other from the piedmonts to the summits of those mountains as vertical ones. By means of the tissue section, the chemical analysis on the non-structural carbohydrate content including soluble sugar and starch, as well as the measurement of environmental parameters in situ, the research will detect the allocation of the non-structural carbohydrate among different tree stem tissues and organs, along with the xylem development. Based on the expected findings from those experiments and analyses, the study may be able to answer the following scientific questions: (1) Does the non-structural carbohydrate content in the “source” organs related to the xylem development, and which period during the xylem development requests the carbohydrate mostly? (2) How, and in what features, does the non-structural carbohydrate content response to the dynamic changes in environmental factors and the tree tissue growth process? And (3) under which conditions and in which growth periods does the growth limitation for Picea meyeri occur as a result of imbalanced carbohydrate allocation?