Spatial Variations In Non-structural Carbohydrates Of Larix Gmelinii, Juglans Mandshurica And Ulmus Japonica

The content and allocation of non-structural carbohydrates (NSC) in trees are considered as a measure of carbon supply for tree growth and survival, and reflects buffering capacity of trees to various stresses. Spatial variation in NSC within trees is fundamental to understanding the NSC allocation in trees, but few quantitative studies on it. In late growing season, sampled by a method of trees analytical, determination NSC concentrations of Manchurian walnut (Juglans mandshurica) and elm (Ulmus japonica) in different basal diameter of canopy branches, and NSC concentrations of larch (Larix gmelinii), walnut and elm in bark, sapwood and heartwood of primary lateral roots, and determination NSC concentrations and vertical changes of the 3 species in bark, sapwood and heartwood of trunk. Then analysis the effects of the spatial variations in NSC concentration of the above-ground part on estimate the NSC content of itself, and estimate the NSC reserves and its allocation of the above-ground part. The main results were below:(1) Organs significantly influenced the crown NSC concentrations for both species. The mean concentrations of TNC of the leaves, new twigs, old branches, and dead branches were 17.6% DM,12.6% DM,5.7% DM, and 2.9% DM, respectively. Most of the NSC concentrations in leaves and new twigs varied insignificantly with basal diameter, age, length and height of the branch. However, the NSC concentration in old branches increased significantly with decreasing basal diameter, age and length of the branch, and with increasing relative height of the branch. Among the branch traits, basal diameter was the best predictor for the NSC concentration of the old branch (the R2 between 0.87 and 0.95). Considering the effect of the spatial variability on the estimation of NSC content, we recommend the sampling protocol that applies the NSC concentration of new twigs and old branches with a diameter of ～3 cm to up-scale the crown NSC content as a simple and practical method.Between species, TNC concentrations in bark and sapwood of primary lateral roots of walnut were highest (13.39% DM and 6.28% DM, respectively), while the highest TNC concentration in heartwood was larch (4.97% DM). Increased NSC concentration with the increasing diameter in lateral roots mainly related to starch. Overall, with the diameter decreasing, the NSC concentration in lateral roots of larch and elm firstly increased and then decreased, but the NSC concentration of walnut decreased with the diameter increasing.(2) The NSC concentrations had significant difference among the 3 species. While the TNC concentration in the sapwood of larch was lower than that of walnut and elm, the TNC of the bark and heartwood were reversed. The mean TNC concentration in bark of the 3 species was 3 and 5 times of those in sapwood and heartwood, respectively. The relative vertical variations of TNC concentrations of the 3 tissues and the total trunk for the 3 species were all about 50%. The NSC concentrations of bark and the total trunk increased with height increasing, while the NSC concentrations of sapwood and heartwood declined slightly with height increasing below the crown. Analyzing the effects of different factors on estimating the NSC content of the trunk, we found that the error introduced by inter-species variation or inter-tissue variation was higher than errors caused by vertical variations.(3) The TNC content of the above-ground part to its biomass for the three species averaged about 3.5%. In the above-ground part, TNC mainly stored in trunk (accounted for 59% of the above-ground part), followed by branches (29%), and foliage accounted for the lowest proportion (12%). In canopy, TNC content in old branches accounted for 97% of the crown branch. In trunk, the TNC contents of bark, sapwood and heartwood to the trunk TNC content averaged 38%,26% and 35%, respectively.In this dissertation, we take larch, walnut and elm as the cases, systematic sampling according to the diameter classes for crown branches and primary lateral roots, and explore the spatial variations in NSC concentrations of crown and roots. Then, systematic analysis the vertical variations in bark, sapwood and heartwood for the three species, and explore the inter-species variation, inter-tissue variation and vertical variation of NSC concentrations in trunk. Contemporary, considering the spatial variability of NSC concentrations within the above-ground part, quantified the impact on estimating the reserves of spatial variation in the above-ground part, optimizing methods for determine NSC concentration by analyzing the error source of NSC storage estimation, this study provided important data and theoretical support for NSC studies of temperate trees.