马尾松与乡土阔叶树种凋落叶木质素降解的混合效应

Mixed Effects on Lignin Degradation in the Litter Leaves of Pinus massoniana and Native Broad-leaved Tree Species

摘要:

为了解森林凋落叶分解过程中木质素的释放规律，对马尾松（Pinus massoniana，P）、檫木（Sassafras tzumu，S）、香樟（Cinnamomum camphora，C）和香椿（Toona sinensis，T）凋落叶分解过程中的木质素降解率进行了研究。结果表明，大部分混合凋落叶的木质素在分解过程中出现富集现象，PT和PC组合的木质素含量在第1年较高，之后降低。而PS、PST、PSC、PCT和PSCT组合在0~6、0~9和15~18个月表现出富集现象，其余时期降低。在不同分解时期，部分混合凋落叶组合的木质素降解率表现出非加和效应，呈协同效应，以春季和夏季的协同效应较强，秋冬季较弱。此外，PSCT6121、PSC622、PS64和PC64的木质素降解率在大部分分解时期（≥6/8）表现出协同效应。因此，马尾松与乡土阔叶树种凋落叶混合后促进了木质素的降解，在马尾松人工林改造过程中，与乡土阔叶树种适当混种，可促进凋落叶中木质素的降解。

Abstract:

To understand the release rule of lignin in the decomposition process of forest leaf litter, the lignin degradation rate of leaf litter of Pinus massoniana (P), Sassafras tzumu (S), Cinnamomum camphora (C) and Toona sinensis (T) was studied. The results showed that lignin in most of mixed litter was enriched during decomposition. The lignin content in combination of PT and PC was high in the first year, and then decreased. However, the lignin content in combination of PS, PST, PSC, PCT and PSCT were enriched at 0-6, 0-9 and 15-18 months, and decreased at other periods. At all decomposition stages, the degradation rate of lignin in some mixed litters showed synergistic effect rather than additive effect, the synergistic effect was stronger in summer and winter than in other seasons. Besides, the lignin degradation rate of PSCT6121, PSC622, PS64 and PC64 showed a synergistic effect in most decomposition stages (≥ 6/8). Therefore, the mixed leaves of P. massoniana and native broad-leaved trees promoted the degradation of lignin, the degradation of lignin in the leaf litter of P. massoniana plantation could be promoted by proper mixing with native broad-leaved species.