Abstract:

Litter is the crucial carrier of soil nutrition transformation. The influence of arbuscular mycorrhizal (AM) fungi on nutrient acquisition in plants has been widely recognized. However, in nutrient-deficient karst habitat, how competitive plants utilize nutrients regulated by AM fungi via litter remain largely unknown. The experimental treatments included the inoculation with or without Glomus etunicatum, the litter addition by the mixed leaves of Broussonetia papyrifera and Carpinus pubescens or no addition, and the competition through the intraspecific competition of B. papyrifera and C. pubescens, respectively, and the interspecific competition mixed both plants. AM fungi differently affected plant on nutrient acquisition, increasing nutrients acquisitions of B. papyrifera in intra- and interspecific competitions while decreasing for C. pubescens. Litter presented opposite influences on N acquisitions of both plants in interspecific competition with AM fungi, being positive for C. pubescens and negative for B. papyrifera, respectively. Under the interaction of AM fungi and litter, nitrogen (N), phosphorus (P) and potassium (K) acquisitions by B. papyrifera and N acquisition by C. pubescens in interspecific competition were all greater than intraspecific competition. In the interspecific competition, the competitive ability of plants on nutrient absorption presented significant species difference, which of B. papyrifera on P and K was significantly increased, while was converse for C. pubescens on K. In conclusion, these results suggest that the interspecific competition presents greater nutrient facilitation compared with intraspecific competition through AM fungi interacting with litter for plants in karst soil.

Key words: arbuscular mycorrhizal fungi, intraspecific competition, interspecific competition, karst, nutrient acquisition