Chen Ya Min, Yu Zai Peng, Wang Min Huang, Wan Xiao Hua, Liu Rui Qiang, Sang Chang Peng, Song Meng Ya, Xiong Jia
Cultivation Base of State Key Laboratory of Humid Subtropical Mountain Ecology, Fuzhou 350007, China.
School of Geographical Science, Fujian Normal University, Fuzhou 350007, China.
Ying Yong Sheng Tai Xue Bao. 2018 May;29(5):1635-1644. doi: 10.13287/j.1001-9332.201805.033.
We conducted a 12-month fine root decomposition experiment under 19-year-old Mytilaria laosensis and Cunninghamia lanceolate plantations to explore the dynamics of nutrient concentration and microbial community composition. The aim of this study was to provide insights into nutrient cycling under plantations with different tree species. Our results showed that the initial concentrations of phosphorus (P) and potassium (K) were significantly higher in the fine root of M. laosensis than those in C. lanceolata, which significantly decreased with decomposition. Nitrogen (N) concentration in fine roots of both species increased with decay time. The variation of N concentration in fine root of C. lanceolata lagged behind that in M. laosensis. During the decomposition, magnesium (Mg) concentration in fine root of C. lanceolata showed no significant changes, but that of M. laosensis decreased at the initial decay stage and increased thereafter and was significantly lower than that of C. lanceolata at the 8th month. The ratio of fungi to bacteria (F/B) of both species decreased at the initial stage and then increased, with significantly higher F/B in fine root of M. laosensis than that of C. lanceolate after one-year decay. Redundancy analysis (RDA) showed that changes in N and K concentrations and C/N ratio explained 37.2%, 14.5% and 14.8% of the variations in microbial community composition of C. lanceolata fine root respectively. However, during the decay of M. laosensis fine root, concentrations of Mg and K were key factors, accounting for 35.9% and 17.6% of the variations in microbial community composition, respectively. We concluded that other nutrients beyond N, such as Mg, might also be an important factor affecting root decomposition in different tree species.
我们在19年生的老挝石梓和杉木人工林下进行了为期12个月的细根分解实验，以探究养分浓度动态和微生物群落组成。本研究的目的是深入了解不同树种人工林下的养分循环。我们的结果表明，老挝石梓细根中磷（P）和钾（K）的初始浓度显著高于杉木，且随着分解过程显著降低。两个树种细根中的氮（N）浓度均随腐烂时间增加。杉木细根中N浓度的变化滞后于老挝石梓。在分解过程中，杉木细根中的镁（Mg）浓度无显著变化，但老挝石梓细根中的Mg浓度在初始腐烂阶段下降，随后上升，且在第8个月时显著低于杉木。两个树种的真菌与细菌比值（F/B）在初始阶段下降，然后上升，经过一年腐烂后，老挝石梓细根中的F/B显著高于杉木。冗余分析（RDA）表明，N和K浓度以及C/N比的变化分别解释了杉木细根微生物群落组成变化的37.2%、14.5%和14.8%。然而，在老挝石梓细根腐烂过程中，Mg和K浓度是关键因素，分别占微生物群落组成变化的35.9%和17.6%。我们得出结论，除N之外的其他养分，如Mg，也可能是影响不同树种根系分解的重要因素。
