A Mixture of Arbuscular Mycorrhizal Fungi Favors Brazilian Pepper Seedlings Under an Intermediate Level of Soil Phosphorus

Abstract

Several tropical woody species are highly responsive to arbuscular mycorrhizal fungi (AMF) and depend on their symbiosis for nutrition and successful establishment in the field. The objective of this study was to evaluate the response of Schinus terebinthifolius, a native species of the Brazilian Atlantic Forest and Caatinga, to inoculation with three AMF species (Dentiscutata heterogama, Gigaspora margarita, and Rhizophagus clarus), either individually or mixed, at different levels of phosphorus fertilization (0, 71, 213, and 650 mg kg−1 of P). We conducted the experiment in 1 kg pots, following a completely randomized design with six replicates per treatment, to evaluate morphological and nutritional traits after 116 days, including stem diameter, plant height, plant biomass, and shoot P content. Our results showed that S. terebinthifolius was highly dependent on mycorrhizae and presented different responses depending on the AMF species. The greatest total biomass accumulation occurred when a mixture of the three AMF species was used, which indicated synergism between the fungi. The highest overall positive response to inoculation were observed at an intermediate P level (213 mg kg−1), and although shoot biomass was reduced at the intermediate P doses, an increase in root biomass compensated for this. These results indicate complementarity as opposed to functional redundancy of the AMF species and highlight the importance of using a mixed inoculum in seedling production of S. terebinthifolius for revegetation programs.