细根寿命的估计是了解细根生产和死亡的关键,对了解陆地生态系统碳分配格局和养分循环具有重要意义。该研究采用微根管(minirhizotron)技术,以23年生樟子松(Pinus sylvestris var.mongolica)人工林为研究对象,对细根生长和死亡过程进行了连续两年的观测。细根寿命的估计采用Kaplan-Meier方法,计算细根的平均寿命(mean longevity)、中值寿命(median longevity)和累积存活率(cumulative survival rate),用对数秩检验(log-rank test)比较单一因素,包括细根直径、根序、出生季节和土层以及菌根侵染对细根寿命的影响。采用Cox比例风险回归分析方法,同时分析上述因素对细根存活的影响程度。结果表明,樟子松细根的生产和死亡具有明显的季节性,春末和夏季(6月和7月)为生产高峰;而死亡高峰出现在夏末至秋末,以及冬季。樟子松细根的平均和中值寿命分别为(322±10)天和(310±15)天,对数秩检验表明,仅考虑单一因子时,细根直径、根序、出生季节和土层以及菌根侵染均对细根寿命有显著影响。Cox回归分析表明,菌根侵染、细根直径和土层是影响樟子松细根寿命的重要因子。细根直径每增加1mm,细根死亡危险率就降低99%,即相当于寿命延长99%;细根出生土层每增加1cm,其寿命延长5%;而菌根侵染后,会导致细根死亡危险率增加175%;但根序和出生季节的影响不显著。这些发现证实:林木细根寿命受到内在与外在因素的共同控制,而多变量回归分析的方法有助于我们全面揭示细根寿命变异的潜在机制。 Estimation of fine root life is the key to understanding fine root production and mortality and is of great importance for understanding the carbon distribution pattern and nutrient cycling in terrestrial ecosystems. In this study, minirhizotron technique was used to study the growth and mortality of fine roots in Pinus sylvestris var. Mongolica plantations for two years. Estimation of fine root lifespan Kaplan-Meier method was used to calculate the mean longevity, median longevity and cumulative survival rate of the fine roots. Log-rank test was used to calculate the average root length, Compare single factors, including effects of fine root diameter, root order, birth season and soil layer and mycorrhizal infection on fine root life. Cox proportional hazards regression analysis was used to analyze the influence of these factors on the survival of fine roots. The results showed that the production and mortality of Pinus sylvestris var. Mongolica were obviously seasonal. The peak of production was in late spring and summer (June and July), while the peak of death occurred in late summer to late autumn and winter. The average and median lifetimes of fine roots of Pinus sylvestris var. Mongolica were (322 ± 10) days and (310 ± 15) days, respectively. Log rank test showed that the root diameter, root order, birth season and soil Both layers and mycorrhizal infection have a significant effect on the fine root life. Cox regression analysis showed that mycorrhizal infection, fine root diameter and soil layer were the important factors affecting the fine root life of Pinus sylvestris. Each additional fine root diameter of 1mm, the risk of fine root death reduced by 99%, which is equivalent to 99% longer life expectancy; fine root for every additional 1cm, its life expectancy increased by 5%; and mycorrhizal infection, will lead to fine The risk of root death increased by 175%; but the effects of root sequencing and birth season were not significant. These findings confirm that the fine root life of trees is controlled by intrinsic and extrinsic factors, and the multivariate regression analysis helps us to fully reveal the underlying mechanism of root-age variation.