Fungos conidiais associados a acículas e galhos em decomposição de araucaria angustifolia (bertol.) kuntze., em floresta ombrófila mista no sul do Brasil

Abstract

The Mixed Ombrophilous Forest, known as the Araucaria Forest, is an important phytophysiognomy that composes the Atlantic Forest, present in the South and Southeast regions of Brazil. The predominant plant species is Araucaria angustifolia, a gymnosperm belonging to the Coniferae order, and to the family Araucariaceae, considered an endangered species. In the Araucaria forest, the litter is composed of approximately 60% of A. angustifolia fragments, being the needles the most dominant substrate with a decomposing mean time of 316 days. Among the decomposers fungi are the conidial fungi, and their diversity is of extreme importance for the degradation of the different substrates founded in litter. Studies focusing on fungi associated with A. angustifolia are mostly related to mycorrhizas and phytopathogens, while knowledge about conidial fungi is still scarce. The aim of this work was to conduct a taxonomic and ecological study of the species of conidial fungi associated with A. angustifolia needles and branches in two conservation units in the south of the country: São Joaquim National Park-SC and National Forest of São Francisco de Paula-RS. Five collection expeditions were carried out quarterly, in the two units between February 2014 and February 2015. were selected ten points by area, and at each point 25 needles and 25 fragments of branches were collected, totaling 5000 substrates analyzed. The samples were sent to the Laboratory of Mycology of the State University of Feira de Santana, and submitted to the washing technique in running tap water. Humid chambers were mounted, maintained at room temperature and observed daily for a period of 60 days. Permanent and semi-permanent slides were made with fungal reproductive structures and identification was based on morphological studies. The slides were added to the Herbarium of the State University of Feira de Santana (HUEFS), and the axenic cultures obtained were deposited in the Collection of Cultures of Microorganisms of Bahia (CCMB). As results of the present study, 135 species of conidial fungi, distributed in 85 genera, were identified. These include a new genus and six new species. It was verified a high species richness, affinity ecological interactions between saprobic/plant. As the NMDS + ANOSIM, SIMPER, Chao 1, Simpson, Equitability and UPGMA analyzes, indicated that the factors substrates (needles and branches) and area are determinant for also the influence in the fungal communities. Thus, the study contributes to the knowledge of the biodiversity and interactions of this group of fungi in the studied plant species, reinforcing the need to preserve it. In addition to contributing to global estimates of diversity, and expanding the geographical distribution of species