中龄和老龄杉木人工林细根序级形态和呼吸特征

Fine Root Morphology and Respiration among Different Branch Orders in Two Plantations of Young and Old Cunninghamia lanceolat

以福建省南平市王台镇溪后村安曹下19年生和91年生杉木人工林为研究对象，对其1—5级细根的形态及呼吸特征进行了比较研究。结果表明：2个林分细根直径、根长、组织密度随序级升高逐渐增大，比根长及比根呼吸随序级升高则减小；2个林分细根仅在4级根之间和5级根之间的直径以及5级根之间的比根呼吸具有显著差异（P〈0．05）。方差分析表明林龄仅对细根直径有极显著影响（P〈0．01），对根长、比根长、组织密度及比根呼吸的影响均不显著；林龄和序级的交互作用对细根直径，比根长及比根呼吸有显著影响（P〈0．05，P〈0．01），对根长和组织密度的影响不显著；序级对两个林分细根直径、根长、比根长、组织密度及比根呼吸的影响均达到极显著水平（P〈0．01）。回归分析表明2个林分细根直径、根长、比根长、组织密度及比根呼吸与序级之间具有三次函数，指数函数，或者幂函数关系。

Fine root morphology and respiration rates of the first to fifth root order were measured in a young （19-year-old） and an old （91-year-old） Chinese fir （Cunninghamia lanceolata） plantation located at Wangtai Town, Nanping City, Fujian province. Our objectives were to determine how root morphology and respiration rates differ across root branch orders and between stand ages. Root diameter, length, and tissue density increased and specific root length （SRL）, specific root respiration （SRR） decreased with increasing root order for both stands, while there was significant difference （P 〈0. 05） in the fourth and fifth order for the root diameter, and the fifth order for the specific root respiration between the young and the old Chinese fir. The ANOVA demonstrated thatstand age had significant effect on root diameter （P 〈 0. 01 ）, but had no significant effect on root length, SRL, tissue density, and SRR. The stand age × root order interaction had significant effect on root diameter, SRLand SRR （P 〈0. 05, P 〈0. 01 ）, but had no significant effect on root length and tissue density; rootorder had significant effect on root diameter, length, SRL, tissue density, and SRR （P 〈0. 01 ）. For both stands, changes in root diameter, length, SRL, tissue density and SRR with root order can be fitted by the cubic, exponential, or power functions.