弓杠岭不同海拔云杉细根生物量及形态特征

海拔变化是多环境因子的梯度效应,细根作为植物吸收水分与养分的重要器官,其性状特征在指示植物的生长和分布等方面意义重大。该研究以弓杠岭2500~3300 m海拔地的云杉(Picea asperata)细根为研究对象,采用根序分级法对云杉1~5级根序的生物量及细根形态(平均直径、比根长、根长密度、比表面积)进行测定,以明确云杉细根生物量及形态性状指标对海拔变化的响应规律以及细根功能间的权衡关系,为解释森林生态系统结构和功能特征提供依据。结果表明:(1)不同海拔云杉细根生物量皆随着根序的上升而增加,且0~10 cm土层生物量显著高于10~20 cm土层。(2)在不同海拔条件和不同土层下的1~5级细根直径都表现出随着根序的上升而增加的变化趋势,比根长、根长密度、比表面积都随着根序的上升而下降。(3)海拔条件对于比根长、根长密度、比表面积有极显著的影响;在细根性状之间,直径与比根长、根长密度、比表面积均呈现极显著负相关关系,而与生物量呈显著正相关关系。研究认为,研究区土层深度以及云杉根序对直径、比根长、根长密度、比表面积、生物量的影响并不一致,即根功能性状对于环境条件的响应方式存在着异质性。

Fine Root Biomass and Its Morphological Characteristics of Picea asperata along an Elevation Gradient of Gonggang Mountains

Altitude change is the gradient effect of multi environmental factors. The fine root is an important organ for plants to absorb water and nutrients, and its characteristics are of great significance in indicating plant growth and distribution. In this study, the fine roots of spruce (Picea asperata) in the Gonggang Mountains at 2 500-3 300 m were taken as the research object. We used the root order classification method to determine the biomass and fine root morphology (average diameter, specific root length, root length density, specific surface area) of spruce to clarify the response of fine root biomass and morphological characters of spruce to altitude changes and the tradeoff between fine root functions. The purpose of this study is to provide a basis for explaining the structure and functional characteristics of a forest ecosystem. The results showed that: (1) the fine root biomass of spruce at different elevations increased with the increase of root order, and the biomass of 0-10 cm soil layer was significantly higher than that of 10-20 cm soil layer. (2) At different elevations and different soil layers, the diameter of 1-5 fine roots increased with the increase of root order, and the specific root length, root length density, and specific surface area decreased with the increase of root order. (3) Altitude had extremely significant effects on specific root length, root length density, and specific surface area, and among fine root traits, diameter had an extremely significant negative correlation with specific root length, root length density, and specific surface area, while had a significant positive correlation with biomass. The study shows that the effects of soil depth and spruce root order on diameter, specific root length, root length density, specific surface area, and biomass are not consistent, that is, there is heterogeneity in the response of root functional traits to environmental conditions.