Comparative influence of three types of natural AMF inoculum on Polylepis australis growth in a field transplant experiment and a greenhouse assay.

SOTERAS, F., RENISON, D. & BECERRA A.

NEW FORESTS

SPRINGER

Lugar: Berlin; Año: 2013 p. 577 - 589

0169-4286

Polylepis forests are one of the most endangered high mountain ecosystemsof South America and reforestation with native Polylepis species has been highly recommended.Greenhouse bioassays were set up to determine the influence of three different soilson growth and phosphorous nutrition of Polylepis australis seedlings. Soils were collectedfrom a grassland, a rare mature forest and a forest degraded due to repeated fires.Weidentifiedthe arbuscular mycorrhizal fungi (AMF) present in the three soils and after 12 months weharvested the seedlings to evaluate root and shoot biomass, plant P content and root colonizationby native AMF and dark septate endophytes (DSE). The soil inocula contained 26AMF morphospecies. Grassland inoculum showed the highest AMF richness, and matureforest showed a different AMF community assembly from grassland and degraded forestinocula. Root biomass and root colonization were highest in seedlings inoculated with matureforest soil, meanwhile shoot biomass and plant P content were similar between all treatments.AMF colonization correlated negatively with DSE and root biomass was negatively correlatedwith DSE colonization, thus these fungal symbionts could be competing for resources.Our results indicate that AMF inoculum from the mature forest stand has the potential toimprove P. australis performance, probably due to the dominance of Glomeraceae andAcaulosporaceae families. However, other soil microorganisms could be together with AMFin the natural inocula, affecting the growth response of P. australis seedlings. Future studiesevaluating the effect of these inocula under field conditions should be carried out.