植物生态学报 ›› 2022, Vol. 46 ›› Issue (7): 797-810.DOI: 10.17521/cjpe.2021.0288

• 研究论文 • 上一篇    下一篇

亚热带森林不同植物及器官来源的可溶性有机质输入对土壤激发效应的影响及其作用机理

甘子莹1, 王浩1, 丁驰1, 雷梅1, 杨晓刚2, 蔡敬琰1, 丘清燕1,*(), 胡亚林1   

  1. 1福建农林大学林学院森林生态稳定同位素研究中心, 福州 350002
    2内蒙古赤峰市克什克腾旗林业和草原局, 内蒙古赤峰 024005
  • 收稿日期:2021-08-11 接受日期:2021-11-05 出版日期:2022-07-20 发布日期:2022-07-15
  • 通讯作者: 丘清燕
  • 作者简介:* (qingyan_qiu@126.com)
  • 基金资助:
    国家自然科学基金促进海峡两岸科技合作联合基金(U1805243);国家自然科学基金(42077094);国家自然科学基金(41703066)

Effects of dissolved organic matter derived from different plant and tissues in a subtropical forest on soil priming effect and the underlying mechanisms

GAN Zi-Ying1, WANG Hao1, DING Chi1, LEI Mei1, YANG Xiao-Gang2, CAI Jing-Yan1, QIU Qing-Yan1,*(), HU Ya-Lin1   

  1. 1Forest Ecological Stable Isotope Research Center, Forestry College, Fujian Agricultural and Forestry University, Fuzhou 350002, China
    2Forestry and Grassland Bureau of Keshiketeng Banner, Chifengshi, Inner Mongolia, Chifeng, Nei Mongol 024005, China
  • Received:2021-08-11 Accepted:2021-11-05 Online:2022-07-20 Published:2022-07-15
  • Contact: QIU Qing-Yan
  • Supported by:
    National Natural Science Foundation of China for Promoting Cross Strait Scientific and Technological Cooperation(U1805243);National Natural Science Foundation of China(42077094);National Natural Science Foundation of China(41703066)

摘要:

外源有机物的输入可以通过正负激发效应影响土壤有机碳(SOC)的矿化。然而, 当前的研究较少考虑不同植物及器官来源可溶性有机质(DOM)输入对土壤激发效应的影响及其作用机理。该研究以武夷山森林土壤为研究对象, 以室内培养的方式向土壤中添加13C标记青冈(Cyclobalanopsis glauca)、杉木(Cunninghamia lanceolata)、木莲(Manglietia fordiana)和相思(Acacia confusa)这4种植物的根和叶来源DOM, 研究不同植物及器官来源DOM输入对土壤激发效应的影响及其作用机理。主要结果: 不同植物及器官来源DOM添加初期加快了SOC的矿化, 呈现正激发效应, 随后转为负激发效应。从整个培养期(90天)的累积激发效应来看, DOM的输入均抑制了SOC的矿化, 使其矿化量减少22%-49%, 其中青冈根DOM输入使SOC的矿化量减少最多, 而由木莲叶DOM输入减少的SOC矿化量最少。DOM输入引起的土壤激发效应强度受不同植物器官影响明显, 具体表现在植物根来源DOM输入所引起的土壤激发效应强度显著高于植物叶来源DOM输入所引起的激发效应强度(相思除外)。DOM的输入总体上提高了土壤微生物生物量碳(MBC)含量、土壤β-葡萄糖苷酶活性、纤维素酶活性以及土壤有效氮含量, 而对微生物群落组成无明显影响。从结构方程模型来看, DOM输入所引起的土壤激发效应主要受土壤微生物对外源碳的利用(13C-MBC)、纤维素酶活性以及土壤有效氮含量的影响, 这些因子的变化可解释植物叶来源DOM和根来源DOM添加处理下土壤激发效应变化的68%和86%。该研究结果表明在土壤氮充足的条件下, DOM的输入可以通过提高微生物生物量、土壤酶活性来加快分解所添加的外源有机物, 从而减少了对SOC的分解。因此, 在该研究中“底物优先利用”是土壤激发效应的主要作用机理。

关键词: 可溶性有机质, 激发效应, 酶活性, 土壤有机碳矿化, 亚热带植物

Abstract:

Aims The input of exogenous organic matter can affect the mineralization of soil organic carbon (SOC) through positive or negative priming effects. However, few studies have considered the effect of dissolved organic matter (DOM) derived from different plant and tissues on soil priming effect and revealed the underlying mechanisms.

Methods In this study, we investigated the different priming effects of 13C-labeled DOM derived from roots and leaves of different plants (i.e., Cyclobalanopsis glauca, Cunninghamia lanceolata, Manglietia fordiana and Acacia confusa) on SOC mineralization and clarifying the underlying mechanisms via an incubation experiment of soils sampled from Wuyi Mountain.

Important findings Inputs of DOM derived from different plant and tissues all accelerated the mineralization of SOC, exhibiting a positive priming effect at the initial stage after DOM input, and then showed a negative priming effect. For the cumulative priming effect during the whole incubation period (90 d), the input of DOM inhibited the mineralization of SOC, with the reduction magnitude ranging from 22% to 49%. Among them, the input of DOM derived from roots of Cyclobalanopsis glauca had the most pronounced effect on the reduction of SOC mineralization, while the input of DOM derived from leaves of M. glauca had the least effect on reduction of SOC mineralization. The intensity of soil priming effect induced by DOM was significantly affected by different plant tissues. DOM derived from plant roots showed more pronounced negative priming effect than DOM derived from plant leaves. In general, DOM input increased soil microbial biomass carbon (MBC) and soil β-glucosidase activities and cellobiohydrolase activities and soil available nitrogen content, but had no significant effect on the composition of soil microbial community. The structural equation model showed that soil priming effect induced by DOM was mainly affected by soil 13C-MBC, cellobiohydrolase activity and soil available nitrogen content. Changes in these factors could explain 68% and 86% of the variation of priming effect induced by plant leaf-derived DOM and root-derived DOM, respectively. The results suggested that if the soil is rich in available nitrogen, DOM input can accelerate the decomposition of exogenous organic matter through increasing microbial biomass and soil enzyme activity, and thus reducing the decomposition of SOC. Therefore, “substrate preferential utilization” is the main mechanism of soil priming effect in this study.

Key words: dissolved organic matter, priming effect, enzyme activity, soil organic carbon mineralization, subtropical plants