【摘要】 为明确杉木(Cunninghamia lanceolata)人工林生长状况与根系生物量的关系,进一步认知植物对环境的适应,为人工林管理提供科学依据,以福建沙县12—14年生杉木人工林为对象,选择林分生物量差异显著的3种林分(分别为高生物量CH、中生物量CM和低生物量CL),采用根钻法对根系和土壤进行取样,测定0—10、10—20、20—40 cm土层土壤C含量、土壤N含量、土壤C:N,杉木不同组分根系[吸收根(1—2级)、运输细根(3—5级)、粗根(5级以上)以及灌草根]生物量密度,并分析了不同组分根系生物量与杉木人工林林分生物量的关系。结果表明,(1)土壤C、N含量在各土层均表现为C_H>C_L(P<0.05)。土壤C:N在0—10 cm和10—20 cm土层无显著差异,但在20—40 cm土层表现为C_L>C_M>C_H(P<0.05);(2)杉木根系主要分布在浅层土壤,各林分0—20 cm土层杉木吸收根,运输细根和粗根分别占0—40 cm土层的84.2%—85.9%、84.6%—85.2%和78.6%—80.0%。尽管吸收根生物量密度仅占总根生物量密度的5.0%—8.7%,但在不同林分间差异显著,在0—10 cm和10—20 cm土层表现为CH>CL(P<0.05)。灌草根生物量密度较低,各林分和土层间均无显著差异;(3)不同林分0—40 cm土层吸收根生物量差异显著,且与林分生物量呈正相关关系(P<0.05)。该研究结果表明土壤C、N含量的差异可能是造成根系生物量和林分生物量存在差异的主要原因,土壤C、N含量高的林分,杉木吸收根生物量和林分生物量均较高。在不同组分的根系中,杉木吸收根对外界环境变化最为敏感,养分条件好的林分和土层,吸收根的生物量也更高。更多还原

【Abstract】 To clarify the relationship between the growth of Cunninghamia lanceolata plantations and root biomass for further understanding the adaptation mechanism of plants to the environment,providing a scientific basis for plantation management,three 12–14-year-old Cunninghamia lanceolata plantations with significantly different stand biomass[high stand biomass （C_H）,medium stand biomass （C_M）,low stand biomass （C_L）]in Shaxian,Fujian Province were selected as the research objects.The roots and soil samples were collected by the root drilling method in each plot.Soil C,soil N,soil C:N and the root biomass of different groups(absorbing roots (1^st–2^nd order),transporting fine roots (3^rd–5^th),coarse roots (>5^th order) and herb roots) in 0–10 cm,10–20 cm and 20–40 cm soil layers were determined.The relationships between root biomass of different groups and stand biomass were also analyzed.The results showed that,（1） the contents of soil C and soil N in each soil layer were C_H>C_L （P<0.05）.However,there was no significant difference in soil C:N in 0–10 cm and 10–20 cm soil layers,but there was a significant difference in 20–40 cm soil layer of different plantations,which showed C_L>C_M>C_H （P<0.05）.（2） Absorbing roots,transporting fine roots and coarse roots were mainly distributed in 0–20 cm soil layer,accounting for 84.2–85.9%,84.6–85.2%and 78.6%–80.0%of each root group in 0–40 cm soil layer,respectively.Though the proportion of absorbing root density only accounted for 5.0%–8.7%of the total root biomass density,there were significant differences between plantations （P<0.05）.In 0–10 cm and 10–20 cm soil layers,the absorbing root biomass densities were C_H>C_L （P<0.05）.However,the root biomass density of herb was low,and there was no significant difference between plantations and soil layers.（3） The biomass of absorbing roots in 0–40 cm soil layer showed differences between plantations and were significantly correlated with stand biomass.That is to say,the higher stand biomass,the higher absorbing root biomass.These results indicate that Cunninghamia lanceolata plantations have higher root biomass densities in soils with higher soil C and soil N.Soil C and soil N may be the main reason for determining the root biomass and growth of Cunninghamia lanceolata in the same area.Of the root groups,absorbing roots are more sensitive to environmental variations than other root groups.Usually,fertile soil can result in higher absorbing root biomass and higher stand biomass.更多还原