中国4种典型森林中常见乔木叶片的非结构性碳水化合物研究

植物叶片的非结构性碳水化合物(non-structural carbohydrates,NSC)不仅为植物的代谢过程提供重要能量，还能一定程度上反映植物对外界环境的适应策略。以温带针阔混交林(长白山)、温带阔叶林(东灵山)、亚热带常绿阔叶林(神农架)和热带雨林(尖峰岭)4种森林类型的树种为研究对象，利用蒽酮比色法测定了163种常见乔木叶片可溶性糖、淀粉和NSC(可溶性糖+淀粉)含量，探讨了不同森林类型植物叶片NSC的差异及其地带性变化规律。结果显示：（1）从森林类型上看，植物叶片NSC含量从北到南递减，即温带针阔混交林(170.79 mg/g)>温带阔叶林(100.27 mg/g)>亚热带常绿阔叶林(91.24 mg/g)>热带雨林(80.13 mg/g)。（2）从生活型上看，无论是落叶树还是阔叶树，其叶片可溶性糖、淀粉和NSC含量均表现为：温带针阔混交林>温带阔叶林>亚热带常绿阔叶林>热带雨林；北方森林叶片可溶性糖、淀粉和NSC含量均表现为落叶树种>常绿树种，或阔叶树种>针叶树种。（3）森林植物叶片NSC含量、可溶性糖与淀粉含量比值与年均温和年均降水量均呈显著负相关。研究表明，森林植物叶片可溶性糖、淀粉和NSC含量以及可溶性糖与淀粉含量比值均具有明显的从北到南递减的地带性规律；其NSC含量以及可溶性糖与淀粉含量比值与温度和水分均呈显著负相关的变化规律可能是植物对外界环境适应的重要机制之一。该研究结果不仅为阐明中国主要森林树种碳代谢和生长适应对策提供了数据基础，而且为理解区域尺度森林植被对未来气候变化的响应机理提供新的视角。

Non-structural Carbohydrates in Leaves of Tree Species from Four Typical Forests in China

Non-structural Carbohydrates (NSC) are not only utilized as energy sources in plant metabolism,but also as the adaptive mechanisms of plant species in response to the environmental changes.Using the anthrone colorimetric method,we measured the NSC content of leaves from 163 tree species collected from four typical forests,which were temperate needle broad-leaved mixed forest,temperate broad-leaved forest,subtropical evergreen broad-leaved forest,and tropical forest,in order to investigate the spatial patterns of leaf NSC along the latitudinal gradient and to explore the relationships between leaf NSC content and climatic factors (temperature and precipitation) on a large scale.The results showed that:(1) The soluble sugar,starch,and NSC in leaves decreased from north to south.For example,the NSC content of temperate needle broad-leaved mixed forests (170.79 mg/g)>temperate broad-leaved forest (100.27 mg/g)>subtropical evergreen broad-leaved forest (91.24 mg/g)>tropical forest (80.13 mg/g).(2) The soluble sugar,starch,and NSC contents of deciduous and broad-leaved trees were similar among different forests;and the order observed was deciduous trees>evergreen trees and broad-leaved trees>coniferous trees.Moreover,the soluble sugar/starch ratio was increased with latitude increasing (R²=0.85,P<0.01).(3) The contents of soluble sugars,starch,and NSC were negatively correlated with mean annual temperature (MAT) and mean annual precipitation (MAP) in the forests (P<0.001).Specifically,soluble sugars,starch,and NSC decreased as MAT and MAP increased.Our findings provide basic data for the carbon metabolism and adaptive strategies of plant species in forests;and provide new insights into the responses and underlying mechanisms of plant species to future climate changes.