Dados do Trabalho

Título

FUNGAL COMMUNITY ASSOCIATED WITH EUCALYPTUS UNDER DIFFERENT P AVAILABILITY IN SOIL

Resumo

Brazil is one of the world references in eucalypt production, a forestall group highly adapted to different environments and with good productivity under a range of soil phosphorus (P) availability. The efficient use of nutrients is essential to a sustainable management of forest trees in tropical soils, where microorganisms related to P cycling play an important role in plant nutrition. Our main goal was to assess the fungal composition in the rhizosphere soil, the mycorrhizal colonization of roots and the plant biomass allocation under contrasting soil P levels. The experiment was conducted for 9 months in a greenhouse with five eucalypt species (Eucalyptus acmenoides, E. grandis, E. globulus, E. tereticornis and Corymbia maculata) grown under low or sufficient soil P availability (4.5 and 10.8 mg/kg of Presin), with five replicates. The DNA from rhizospheric soil was submitted to ITS amplicon sequencing, the roots were segmented to quantify arbuscular mycorrhizal (AM) fungi by optical microscopy, and the plant growth was evaluated. The alpha-diversity index (Shannon) of fungi increased about 60% and 50% in response to soil P availability in the rhizosphere of E. globulus and C. maculata, respectively. The proportion of the most abundant fungal Family and the beta diversity (NMDS ordination) differed between P levels in soil. The intensity of the AM colonization in the root system and in the root fragments (m%) were higher under sufficient soil P availability. The highest average of m% was in C. maculata and E. tereticornis, with 24% and 17% of the roots colonized by AM fungi in soil with sufficient P. Under P limitation, E. globulus had the lowest stem and leaves biomass (2 g and 2.5 g, respectively) and C. maculata had higher total biomass production (15.1 g). Soil P availability modulated the rhizospheric fungal community and the mycorrhizal colonization which may influence the biomass production efficiency of eucalypt species under low P availability.

Palavras-chave

forestry; plant nutrition; shoot biomass, rhizosphere, mycorrhiza.

Instituição financiadora

Financial support process nº2016/25498-0 and nº 2021/05126-9, Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP).

Agradecimentos

Thanks to everyone from LaFiMP in the Institute of Biology of UNICAMP.