以川中丘陵区柏木低效林林窗改造初期种植的银木和香椿细根为研究对象,以未改造的柏木纯林为对照,采用LI-8100土壤碳通量测量系统测定银木、香椿和柏木1～5级细根的原位呼吸速率,并探讨细根形态结构和养分元素浓度与细根呼吸的相关关系,以揭示细根结构与功能异质性.结果表明:银木、香椿和柏木细根的直径、根长、组织碳浓度均随着根序级别的增加而增加,而它们细根的比根长、组织氮浓度和比根呼吸速率均随着根序的增加而降低,树种、根序级及其交互作用对3个树种细根形态、养分浓度和比根呼吸均有显著或极显著影响.回归分析显示,3个树种比根呼吸速率均随细根直径、比根长、N浓度变化呈现出系统性的变化,三者分别能解释64.7％、87.6％和、67.6％的比根呼吸变异.可见,细根在形态和功能上存在明显的异质性,且细根的形态特征、组织化学含量和生理功能之间存在着紧密的联系,为理解植物根系结构与功能变异提供了依据.%Taking the fine roots of Cinnamomum septentrionale and Toona sinensis which were planted during early preliminary stage of low-efficiency Cupressus funebris forests transformation in the hilly region of central Sichuan as research objects,while using the unmodified pure C.funebris forest as control,we determined in situ respiration rates by applying a LI-8100 soil carbon flux measurement system of the 1st-5th order roots and discussed the relationship among the morphological structure and the nutrient concentration of fine roots and respiration to reveal the structural and functional heterogeneity of fine roots.The results showed that the diameter of fine roots,root length and tissue carbon concentration of C.septentrionale,T.sinensis and C.funebris increased with the roots order increased,while specific root length (SRL),tissue nitrogen concentration and specific root respiration rate (SRR) reduced.And species,root order and their interactions showed that the morphology,nutrient concentrations and SRR of these three species fine roots were highly significant effect (P＜0.01).Regression analysis indicated that three species SRR of these three species fine roots altered as diameter,SRL and tissue nitrogen concentration changed,which explained the variation with 64.7 ％,87.6 ％ and 67.6 ％ of SRR,respectively.These results suggested that there was a close link among morphological characteristics of fine roots,the chemical contents and physiological functions,which provided an important basis to understand the structural and functional variation of plant roots.
展开▼
