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采集欧美杨107Ⅰ代和Ⅱ代人工林细根样品,分析杨树不同根序细根数量特征(根长度、表面积和生物量)和形态特征(比根长、根长密度、根组织密度)对季节波动的响应及其代际差异.结果表明:杨树各根序细根数量特征(根长度、表面积和生物量)均呈明显的季节变化,且具有明显的根序差异性.低级根序细根数量特征季节差异显著,细根生物量在生长季显著增加而生长季后显著下降.高级根序细根比根长季节波动显著,而根长密度和根组织密度等形态特征波动较小.连作导致人工林杨树1~2级细根长度、生物量、比根长和根长密度在生长季显著增大.1级细根数量特征与土壤温湿度呈显著正相关,与土壤有机质和速效氮含量呈显著负相关;而2级细根数量特征仅与土壤养分显著相关.杨树人工林细根特征的季节动态及代际差异体现了杨树对细根的碳投入变化,因连作引发的土壤养分匮乏可能引发植株对根系的碳投入增加,这种碳分配格局与人工林地上部分生产力形成密切相关.
Fine root samples of poplar 107Ⅰ and Ⅱ of European and American poplars were collected to analyze the effects of different root numbers (root length, surface area and biomass) and morphological characteristics (root length, root length and root density) The results showed that the fine root number, root length, surface area and biomass of each root of poplar showed obvious seasonal variation and obvious difference in root order. The quantitative characteristics of the seasonal variation were significant, the fine root biomass increased significantly during the growing season and decreased significantly after the growing season.High-order roots had more seasonal variation than the root length and less fluctuation of the root length density and the root tissue density, The fine root length, biomass, specific root length and root length density of poplar 1 ~ 2 in the plantation increased significantly in the growing season.The quantitative characteristics of fine root in level 1 were positively correlated with the soil temperature and humidity, While the content of fine root of number 2 was only significantly correlated with soil nutrient.The seasonal dynamics and interdependency of fine root characteristics of poplar plantation reflected the variation of carbon input of poplar to fine root, The lack of soil nutrients may lead to increased plant carbon inputs into the root system, which is closely related to the formation of aboveground productivity of plantations.