摘要
树体中的非结构性碳水化合物(NSC)浓度、含量及其分配反映了树木整体的碳供应状况,是决定树木生长和存活的关键因子,也是构建树木碳平衡模型的关键参数。温带树种的NSC尚缺乏系统研究。该文测定了特性各异的3种温带树种在生长盛期的NSC及其组分的浓度和含量以及分配格局的种间种内变异。结果表明,NSC及其组分的浓度在树种和组织之间差异显著,可溶性糖、淀粉和总NSC浓度分别在0.65–8.45、1.96–5.95和3.00–13.90 g.100 g–1DM之间波动。NSC及其组分含量的大小依次为:兴安落叶松(Larix gmelinii)>蒙古栎(Quercus mongolica)>红松(Pinus koraiensis),其中叶和根中的浓度较高。树干中的NSC及其组分浓度的纵向变化不显著,但其心材与边材之间的浓度差异却随树种和NSC组分而异,表现为心边材的可溶性糖浓度差异不显著,但其淀粉和总NSC浓度差异显著。不同直径根系的NSC及其组分浓度在2种针叶树种中差异不显著,但在蒙古栎中差异显著。蒙古栎将可溶性糖主要投资到地上生长,而2种针叶树将更多的可溶性糖投资到根系生长。淀粉的主要储存库为树干,其在树体内的分布格局与可溶性糖正相反,因而使总NSC在树根和树枝中的分配趋于较平衡状态。在树干中,除了2种针叶树的可溶性糖库以边材为主外,心材是淀粉和总NSC的主要储存库。在树根中,粗根是NSC及其组分的优势储存库。该研究中3种温带树种的NSC及其组分的浓度和含量的种间和种内变化,反映了这些树种的生长对策和体内碳源汇强度的差异。
Aims The content and allocation of nonstructural carbohydrates（NSC） in trees reflect whole-tree carbon balance regimes,and are crucial to determine growth / survivorship trade-off of trees and model tree carbon balance between uptake and investments in structure or loss.Our objective was to examine the concentration and allocation patterns of NSC for three temperate tree species,i.e.,Korean pine（Pinus koraiensis）,Dahurian larch（Larix gmelinii） and Mongolian oak（Quercus mongolica）.Methods During the mid-growing season（July of 2010）,all biomass tissues,including foliage,branch,stem and root,were randomly sampled from three dominant trees for each species.The stem samples were taken from mid-canopy and breast height,and divided into sapwood and heartwood,while the root samples were divided into fine（diameter 2 mm）,medium（2–5 mm） and coarse roots（5 mm）.All samples were dried,ground,and analyzed for NSC concentrations（including soluble sugar and starch） with a modified phenol-sulfuric acid method.Important findings The concentrations of NSC and its component differed significantly among species and tissues.Concentration ranges were 0.65–8.45,1.96–5.95 and 3.00–13.90 g.100 g –1 DM for soluble sugar,starch,and NSC,respectively.On average,the contents of NSC and its components followed the order of： larch oak pine.Concentrations in the foliage and roots were higher than those in other tissues.Within the stems,the longitudinal variations in the concentrations of NSC and its components were insignificant,whereas the differences between sapwood and heartwood varied with species and NSC components.There was no significant difference in soluble sugar concentration between sapwood and heartwood,but significant differences in starch and total NSC concentration.The concentrations of NSC and its components varied insignificantly with root diameters for larch and pine,but significantly for oak.Oak invested more soluble sugar to aboveground growth,whereas the two conifers did more to roots.Nevertheless,starch was mainly reserved in stems,and the intra-tree allocation pattern of starch exhibited an opposite trend to soluble sugar,leading the total NSC to be relatively balanced between roots and branches.In the stems,heartwood was the major reserve of NSC and starch,while sapwood was the major reserve of soluble sugar for the two conifers.In the roots,coarse root was the dominant reserves of NSC and its components.We concluded that the inter-and intra-specific variations in the NSC and its components in this study reflect differences in growth strategies and within-tree carbon source / sink strength for the three temperate tree species.
出处
《植物生态学报》
CAS
CSCD
北大核心
2011年第12期1245-1255,共11页
Chinese Journal of Plant Ecology
基金
"十二五"科技支撑项目(2011BAD37B01)
林业公益性行业科研专项(200804001)
国家自然科学基金(30625010)
国家林业局重点项目(2006-77)共同资助
关键词
碳分配
兴安落叶松
红松
蒙古栎
可溶性糖
淀粉
carbon allocation
Larix gmelinii
Pinus koraiensis
Quercus mongolica
soluble sugar
starch
