Chin J Plant Ecol ›› 2022, Vol. 46 ›› Issue (6): 624-631.DOI: 10.17521/cjpe.2021.0194

• Research Articles • Previous Articles     Next Articles

Testing Janzen-Connell hypothesis based on plant-soil feedbacks in a temperate coniferous and broadleaved mixed forest

QIN Jiang-Huan, ZHANG Chun-Yu, ZHAO Xiu-Hai()   

  1. Research Center of Forest Management Engineering of State Forestry and Grassland Administration, Beijing Forestry University, Beijing 100083, China
  • Received:2021-05-20 Accepted:2021-09-21 Online:2022-06-20 Published:2022-06-09
  • Contact: ZHAO Xiu-Hai
  • Supported by:
    National Natural Science Foundation of China(31971650)

Abstract:

Aims Current research on the maintenance mechanisms of forest biodiversity mainly focuses on the stage of examining the abundance of aboveground organisms. However, many gaps remain in our knowledge of interactions between species and on whether the underground fungi affect the maintenance of biodiversity. This study explores the role of soil fungi in maintenance of biodiversity and the relationship between plant-soil feedbacks and plant growth. We selected four tree species in a broadleaved Korean pine forest in Northeast China, and used controlled seedling planting experiments to test the Janzen-Connell hypothesis.

Methods Experimental treatments included fungicide application and controlled seedling planting of four tree species (Pinus koraiensis, Fraxinus mandshurica, Phellodendron amurenseand Tilia amurensis) in Jiaohe forest farm, Jilin Province. Biotic and specific feedbacks were assessed using the fungicide treatment and the control seedling planting of different tree species. Soil fungal diversity was determined by high-throughput sequencing method and tested for differences among different treatments. The relationships of the two feedback types with tree species, functional types of fungi and soil were analyzed by variance partitioning analysis (VPA).

Important findings Fungicide treatment did not significantly affect the biotic feedback, and seedling biomass in conspecific soil did not show significant distance dependence. The specific feedbacks were not significantly improved by presence of different tree species. In addition, VPA showed that the most important factor affecting plant-soil feedbacks was inherent species characteristics, with the influence of soil and fungi varying with the feedback type. This study identified the factors influencing plant-soil feedbacks in mixed forest of temperate zone, and demonstrated the variability of Janzen-Connell hypothesis with temperate forest tree species, laying a foundation for better understanding the interactions between species and the underlying regulation mechanisms.

Key words: Janzen-Connell hypothesis, plant-soil feedback, distance dependence, coniferous and broadleaved mixed forest, seedling, soil fungi