摘要
以16年生杉木人工林为对象，用根系图像分析软件（win RHIZO TRON 2005a）和CN元素分析仪（Elementar Vario EL Ⅲ）测定4个径级（0-2mm、2-5mm、5-10mm、10-20mm）根的形态参数和C、N含量，用土壤呼吸测定系统LI-8100（LI-COR，USA）测定各径级离体根呼吸速率，分析不同径级根参数特点及其与根呼吸的相关性，并对根系离体后呼吸速率变化和测定时间选择进行了探讨。研究结果表明：不同径级之间的根参数存在显著性的差异，根参数之间存在显著的相关性；细根（〈2mm径级）的呼吸速率和〉2mm径级根的平均呼吸速率分别为1.145±0.249nmolCO2gDM^-1s^-1和0.350±0.040nmolCO2gDM^-1s^-1，前者显著大于后者；离体根呼吸速率与根N含量呈显著线性正相关，与根C含量、C／N呈显著负相关，与比根长呈极显著正相关．细根离体后呼吸速率应立即测定，而〉2mm的根测定时间可以适当延后。
Root respiration is an important component in carbon cycles of forest ecosystems. Quantifying root respiration is necessary for exactly calculating net primary production and carbon balance in forest ecosystems. It has been realized that tree root respiration is related, one way or another, to root system biological parameters. In this study root morphologic parame- ters andC, N content of four diameter classes （0-2mm, 2-5mm, 5-10mm, 10-20mm） were analyzed for 16 years old trees of Cunninghamia lanceolata （Lamb.） Hook. by Win RHIZO TRON 2005a and Elementar Vario EL Ⅲ, and excised root respiration rates of different diameter classes were measured by Soil Respiration Measuring System （Li-8100. LI-COR, USA）; and characters of root parameters and their relationship with respiration were analyzed; we also explored the most appropriate time period for measuring root respiration after excised based on fluctuation of the excised roots respiration. Results showed that the variation in the respective root parameters for different diameter classes was significant and, the root parameters were correlated with each other; the mean respiration rate （±SE） of roots for diameter of 〈2 mm （1.145±0.249 nmolCO2 gDM^-1 s^-1） was significantly larger than that of 〉 2mm （0.35±0.040 nmolCO2 gDM^-1 s^-1 ） ; while C contents and C/N were signifi- cantly positive correlative with excised root respiration rate, the N content of fine root presented pronounced negative relationship and so did the parameter Specific Length of roots. We found that excised root respiration of 〈 2 mm diameter should be immediately measured, while for roots of 〉 2 mm the measuring time duration could be extended without significant effect on respiration rates results.
出处
《亚热带资源与环境学报》
2008年第2期19-24,共6页
Journal of Subtropical Resources and Environment
基金
福建省科技计划项目(K04018)
福建省自然科学基金资助项目(D0510018)
关键词
杉木
N含量
C含量
C/N
比根长
呼吸速率
离体根法
LI-8100
Chinese fir
N content
C content
C/N ratio
Specific Length of Roots
Rootrespiration rates
in vitro root methods
LI-8100
