Response Of Biomass And Physiological Characteristics For Abies Nephrolepies Sapling Along The Altitudinal Gradient Of Chang Bai Mountain,Northeastern China

The aim of this study was to explore the physiological and ecological adaptation mechanism of dark coniferous species under different environment,and to provide data supporting for the research on the physiology of the dark coniferous species.We analyzed the photosynthesis,spectral index and biomass allocation of Abies nephrolepies saplings at different elevations,which help us to understand the effects of elevations on plants.The correlation between leaf spectral index and leaf pigment was also analyzed.The results are as follows:1)The Light saturation point(LST),light-saturated photosynthsis(Pmax)of A.nephrolepies saplings at 1400m were higher than in the other three elevations;while the dark respiratory rate(Rd),light compensation point(LCP)of A.nephrolepies saplings were lower than in the other three elevations.In addition,SUE,WUE of A.nephrolepies saplings were higher than in the other three elevations.2)The correlation between leaf chlorophyll content and leaf spectral index(mSR705,ChINDI and NDVI)was significant at altitudes of 900m,1200m and 1400m.The correlation between spectral index NDVI and leaf chlorophyll was not significant at altitudes of 1500m.At the same time,the correlation between A.nephrolepies saplings leaf spectral index CAI and leaf carotenoid content was significant.In addition,A significant correlation was found between the SIPI,PSRI and the ratio of carotenoids to chlorophyll(Car./Chl.).3)The chlorophyll reflex index(mSR705 and ChlNDI)of the leaves of A.nephrolepies saplings were increased and then decreased from 900m to 1500m,the altitude of 1400m is mostly.Photochemical reflectance index(PRI)indicated higher PAR use effciency at 1400m than other elevations.Carotenoid index(CAI)indicated the carotenoid concentrations among 900m-1400m were not significantly difference.Carotenoid index(CAI)indicated lower PAR use effciency at 1500m than lower-elevations.4)The aboveground and belowground biomass and total biomass of the A.nephrolepies saplings were highest at 1400m and had no correlation with elevation.The aboveground and belowground biomass of the A.nephrolepies saplings were increased with the increase of total biomass.The proportion of fine root and foliage biomass was increased significantly with the elevation gradient.But,the proportion of coarse root and trunk biomass was significantly reduced.