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细根是植物吸收水分和养分的主要器官,细根生物量对盐土地人工绿化植被生态修复具有重要意义。以3种人工林为研究对象,分别对其细根生物量、垂直分布及各形态指标的变化特征进行分析。结果表明,响叶杨(Populus adenopoda)林、普陀樟(Cinnamomum japonicum)林和落羽杉(Taxodium distichum)林0–40 cm土层的平均细根生物量分别为1 699.75、498.50和520.06 g·m~(–2)。3种林分在0–10 cm土层中的细根生物量占整个细根生物量的50%以上,随着土层的增加细根生物量呈现指数减少(P<0.05)。在生长季节内细根生物量呈双峰变化,不同月份间存在显著差异。活细根生物量和比根长均表现为普陀樟林<落羽杉林<响叶杨林。将细根各项指标与3种环境因子进行相关分析,发现土壤含水量与活细根生物量及根长密度呈显著正相关(P<0.01)。CCA分析表明,土壤含盐量是影响活细根各项指标垂直变化的主要限制因子,而高盐可能对细根生物量及分布有不利影响。
Fine roots are the main organs that plants absorb moisture and nutrients. Fine root biomass is of great importance to the ecological restoration of artificial green vegetation in saline lands. Taking three kinds of plantations as the research object, the change characteristics of fine root biomass, vertical distribution and each morphological index were analyzed. The results showed that the average fine root biomass of Populus adenopoda, Cinnamomum japonicum and Taxodium distichum were 0 699.75, 498.50 and 520.06 g · m ~ (-2). The fine root biomass in 0-10 cm soil layer accounted for more than 50% of the total fine root biomass in three kinds of forests. The index of fine root biomass decreased with the increase of soil layers (P <0.05). The fine root biomass showed a bimodal variation during the growing season, with significant differences between months. Live fine root biomass and specific root length are manifested as Perus camphor Ringwood forest. Correlation analysis between the indexes of fine roots and three environmental factors showed that there was a significant positive correlation between soil water content and root biomass and root biomass (P <0.01). CCA analysis showed that soil salinity was the main limiting factor affecting the vertical variation of various indicators of living fine roots, while high salinity could have an adverse effect on fine root biomass and distribution.