Mechanisms of rhizosphere priming effects and their ecological significance

Priming effects are defined as “strong short-term changes in the turnover of soil organic matter caused by moderate treatments of the soil”. Rhizosphere is the most important place, where the priming effects take place. Rhizosphere priming effects reflect the turnover rate of soil carbon and nitrogen, and affect the acquisition of nutrients by plants and microorganisms, as well as their competition for nutrients, thus maintaining nutrient balance among the various components of an ecosystem. Although there has been a general understanding on the occurrence of rhizosphere priming effects, the mechanisms underlying their role in soil carbon and nitrogen transformations and their ecological significance are still not fully comprehended. This paper provides a synthesis of the latest advancement in studies of the rhizosphere priming effects. On the basis of reviews of research history and identification of the hotspots, we first put forward a mechanism underlying the occurrence of rhizosphere priming effects, and then examined the biotic and abiotic factors influencing the rhizosphere priming effects. The ecological significance and outlooks of research in the rhizosphere priming effects were discussed and clarified.