Seleção de substratos e fungos micorrízicos arbusculares para formação de mudas de espécies arbóreas nativas da Mata Atlântica

Abstract

The inoculation of tree species changes with arbuscular mycorrhizal fungi (AMF) can improve growth in the forest nursery and development after transplanting. Therefore, the general objective of this work was to select substrates and AMF communities for the production of seedlings of tree species, so that they are of superior quality when compared to the seedlings in which there was no inoculation. For this, in the first chapter, four substrates (RAD, SC1, ESTIPE and SC2) were evaluated for mycorrhizal colonization and sporulation of the AMF community. Direct sowing of Brachiaria decumbens was carried out in plastic containers of 280 cm³ and inoculation with approximately 110 spores of a mixture of AMF. It was verified that the RAD substrate possessed a large number of native AMF spores, and increased this number after inoculation and cultivation of the brachiaria, maintaining high diversity and being more conducive to AMF, and the SC2 substrate was quite conduscent to the inoculated mycorrhizal fungi, maintaining high number of spores, high colonization rate and high diversity of AMF species after cultivation of brachiaria. In the second chapter, the growth and mycorrhization of angico, brauna and garapa saplings produced in plastic containers of 280 cm³. Each species composed an experiment, installed in a completely randomized design and 2x4 factorial scheme, with two types of substrates: RAD and SC2, and four treatments: Control without inoculation, Control without inoculation fertilized, Community of selected FMAs and Community of native AMF. It was verified that the dry masses of the aerial part and of the root system, leaf area, specific foliar area, root volume, mycorrhizal colonization, number of spores and inoculation efficiency. The results indicated that brauna and garapa did not tolerate SC2 substrate fertilized in the absence of AMF. In 60% of the comparative situations (variables and tree species), AMF communities did not promote differentiated growth responses, but the native community surpassed the selected community in 27% of situations and vice versa in only 7%. In the three tree species there was no difference in mycorrhizal colonization and sporulation of AMF between the selected and native communities. Angico was the species that promoted greater colonization and sporulation of AMF, and brauna was the species where colonization and sporulation were minor. From the joint analysis of the results, it is inferred that the forest species respond differently to the substrates, and the inoculation of AMF communities in seedlings of tree species is capable of promoting improvements in seedling growth.