ABSTRACT The use of mycorrhiza is a promising biotechnology that makes coffee cultivation sustainable in the use of fertilizers. In this sense, plant growth and phosphorus contents were assessed in coffee inoculated with Rhizophagus clarus, Claroideoglomus etunicatum and Dentiscutata heterogama in soil fertilized with 0, 0.74, 1.48 and 2.96 g P2O5 kg-1. The experimental design was a randomized block design in a 4 × 4 factorial scheme with four replications. The mycorrhizal seedlings were previously produced and later transplanted to pots, simulating the field planting. The assessments were performed 150 days after transplanting. All variables were influenced by inoculation, but the effects were dependent on P doses. P doses higher than 50% of the recommended dose (0.74 g P2O5 kg-1) decreased the benefit of mycorrhiza. The fungi Rhizophagus clarus and Claroideoglomus etunicatum promoted a higher growth of coffee plants when compared to non-inoculated plants in non-sterilized soils and with a reduction in the applied P. | RESUMO O uso de micorriza é uma biotecnologia promissora a fim de tornar a cafeicultura sustentável na utilização de adubos. Nesse sentido, foi avaliado o crescimento e teores de fósforo em cafeeiro inoculado com Rhizophagus clarus, Claroideoglomus etunicatum e Dentiscutata heterogama em solo adubado com 0; 0,74; 1,48 e 2,96 g kg-1 de P2O5. O experimento foi delineado em blocos e os tratamentos foram compostos pelo fatorial 4 x 4, com quatro repetições. As mudas micorrizadas foram previamente produzidas e posteriormente transplantadas para vasos, simulando o plantio no campo. As avaliações foram realizadas aos 150 dias após o transplantio. Todas as variáveis analisadas foram influenciadas pela inoculação, porém os efeitos foram dependentes das doses de P. Doses de P maiores que 50% da dose recomendada (0,74 g kg-1 de P2O5) diminuem o benefício da micorriza. Os fungos Rhizophagus clarus e Claroideoglomus etunicatum promovem maior crescimento das plantas de café em relação às plantas não inoculadas, nos solos não esterilizados e com redução do P aplicado.

ABSTRACT Arbuscular mycorrhizal fungi (AMF) and dark septate endophytic fungi (DSE) promote increase in plant biomass, depending on the soil and climate conditions and the interactions with the host plant. The objective of this study was to evaluate the interaction of exotic arbuscular mycorrhizal fungi and native DSE fungi on the initial growth of P. millegrana. A completely randomized experimental design comprising the Paspallum millegrana cutilvar with the following treatments: control - without AMF, and three exotic AMF isolates (UFLA351 - Rhizoglomus clarum, UFLA372 - Claroideoglomus etunicatum and UFLA401 - Acaulospora morrowiae), with four replications each. P. millegrana grass was colonized by exotic AMF by R. clarum (UFLA351, 11.9%), C. etunicatum (UFLA372, 39.6%), and A. morrowiae (UFLA401, 51.2%). P. millegrana was also colonized by native DSE fungi, but these did not interfere with the colonization by exotic AMF and plant development. P. millegrana is responsive to the inoculation of UFLAs isolates of exotic AMF, which may contribute to the grass growth and survival under field conditions. The process of surface disinfestation of seeds does not eliminate endophytic microorganisms, whose presence may influence plant colonization by AMF, as well as development of the host plant. | RESUMO Os fungos micorrízicos arbusculares (FMA) e os endofíticos “dark septate” (DSE) podem promover o incremento da biomassa vegetal, a depender das condições edafoclimáticas e da interação com a planta hospedeira. O objetivo deste trabalho foi avaliar a interação de fungos micorrízicos arbusculares exóticos e fungos endofíticos DSE nativos no crescimento inicial de Paspalum millegrana Schrad. ex Schult. O delineamento experimental utilizado foi inteiramente casualizado composto pelo cultivo de Paspallum millegrana em quatro tratamentos (controle - sem FMA, e três isolados de FMA exóticos: UFLA351 - Rhizoglomus clarum; UFLA372 - Claroideoglomus etunicatum e UFLA401 - Acaulospora morrowiae), com quatro repetições. O capim P. millegrana é colonizado por FMA exóticos das espécies R. clarum (UFLA351; 11,9%), C. etunicatum (UFLA372; 39,6%) e A. morrowiae (UFLA401; 51,2%). O P. millegrana foi colonizado por fungos endofíticos DSE nativos, mas estes não interferem na colonização por FMA exóticos e no desenvolvimento das plantas. O P. millegrana foi responsivo à inoculação dos isolados UFLAs de FMA exóticos, o que pode contribuir para o crescimento e sobrevivência do capim em condições de campo. E o processo de desinfestação superficial das sementes não elimina micro-organismos endofíticos, cuja presença pode influenciar na colonização das plantas por FMA, bem como no desenvolvimento da planta hospedeira.

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.