关键词: 黄土高原, 森林植被, 调节作用

Abstract: As one of the main tree species in northeast and western China, spruce is of great significance in forest carbon sequestration, water conservation and ecological safety barrier. The dynamics of non-structural carbon (NSC) provides an important reference for studying forest carbon storage and carbon supply. We recorded the phenology of 10-year-old saplings of seven spruce species in a common garden, and measured the NSC concentration and net photosynthetic rate of current and one-year-old needles. The results showed that the sequencing of germinating stage was Picea asperata < P. wilsonii< P. meyeri < P. likiangensisvar. linzhiensis<P. crassifolia<P. likiangensis var. rubescens<P. koraiensis, the sequencing of extension period was P. meyeri < P. crassifolia < P. asperata < P. wilsonii < P. koraiensis < P. likiangensis var. ubescens< P. likiangensisvar. linzhiensis, but the bud-break period had no variation among species. The phenological differences were manifested by phenotypic acclimation to environmental changes, for instance, effective cumulative temperature (R=0.996^*), soil moisture content (R=-0.807^*), and adaptation to the original habitat. The seasonal dynamics of NSC concentration was similaramong species. The variation of starch concentration of current and one-year-old needles was unimodal and that of soluble sugars increased first and then tended to be stable. Moreover, the NSC concentration of current-year needles was lower than one-year-old needles, with the starch concentration ranging from 20 to 50 mg·g^-1 and 70 to 150 mg·g^-1, and the soluble sugars ranging from 80 to 150 mg·g^-1 and 200 to 350 mg·g^-1, respectively. Furthermore, the net photosynthetic rate always increased after the starch concentration decreased in both types of needles, suggesting the coordination between the net photosynthetic rate and the concentrations of starch and soluble sugar. Our results provide reference for comprehensive understanding NSC seasonal dynamics of different Picea species.