Banca de DEFESA: JULIANA APARECIDA SOUZA LEROY

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JULIANA APARECIDA SOUZA LEROY
DATE: 31/08/2022
TIME: 14:00
LOCAL: https://meet.google.com/svo-mybf-hst
TITLE:

ARBUSCULAR MYCORRHIZAL FUNGI ASSOCIATED WITH AQUATIC MACROPHYTES IN TROPICAL RIVERS IN BRAZIL

KEY WORDS:

Aquatic plants; Mycorrhiza; Macroalgae; Lotic ecosystems; Diversity.

PAGES: 140
BIG AREA: Ciências Biológicas
AREA: Botânica
SUBÁREA: Taxonomia Vegetal
SPECIALTY: Taxonomia de Criptógamos
SUMMARY:

Studies on the symbiose between arbuscular mycorrhizal fungi (AMF) and roots of aquatic macrophytes are recent, where the diversity and ecological role of these fungi in wetlands remains poorly understood. Most of the work focuses on the terrestrial environment, creating a gap in the understanding of the role of AMF, especially in hosts whose roots are constantly submerged. In this study, the presence of mycorrhizal colonization in roots of submerged and floating macrophytes was evaluated, also analyzing the sediment of the rhizosphere of the hosts, including macroalgae of the genus Chara, in tropical lotic environments. Thus, the study was divided into two stages. The first step was to evaluate the presence of AMF in macroalgae of the genus Chara. For this, the presence of colonization in algal rhizoids in five different lotic environments in Brazil was investigated, also evaluating the presence of spores in the rhizosphere. Twenty-five species were found in the rhizosphere of Chara sp., belonging mainly to the families Acaulosporaceae (11) and Glomeraceae (8). The rivers showed low species richness with Rio do Gozo (16), followed by Uma (8), Pratinha (2), Cuitegí (2) and Pandeiros (1). Despite the occurrence of AMF spores in the aquatic sediment, there is no mycorrhizal colonization in the rhizoids of Chara sp. for the analyzed field conditions. In the second stage, AMF colonization was investigated in 61 aquatic macrophytes of the biological types submerged fixed, fixed floating and free floating, which are in permanent contact with water, in nine rivers in the state of Rio Grande do Norte. Of the investigated hosts (61) 15 species showed colonization by AMF (24.5%). The macrophytes studied from the Rivers Trairí, Doce, Brandão and Piranhas did not show colonization by AMF, whereas the Rivers Catu, Pitimbú and Pium had colonization by AMF greater than 50%. Colonization by AMF was reported for the first time in 6 of the 15 colonized macrophytes. The species that showed the highest colonization rate were Nymphoides humboldtiana (92%) and Bacopa aquatica (75%). Regarding colonization and colonization by life form, the submerged macrophyte species studied showed 52% colonization by AMF, while the fixed floating 18% and the free floating only 8%. A total of 43 species were recovered from the aquatic sediments of the nine rivers of RN, where the most representative families were Glomeraceae (33.3%) and Acaulosporaceae (31%). The largest number of species was recovered from the Pium River (17), followed by Piranha (14) and Catu (12). Regarding the comparison between the AMF communities and the rivers, it suggests that the AMF communities of the Pium and Piranha rivers are more similar, as are the communities of the Doce and Trairi rivers and the rivers and the Catu and Boa Cica rivers. The composition of AMF communities did not differ when tested in relation to biological types of hosts and interaction between habits and rivers. AMF species richness was highest in fixed floating macrophytes (29), followed by fixed submerged (28) and free floating (11). The greatest diversity of AMF species was observed in the rhizosphere sediment of fixed floating macrophytes, despite the low colonization rate. The results of this study confirm the presence of AMF colonization in vascular aquatic macrophytes and the absence of it in macroalgae (Chara) in lotic environments, where the aquatic sediment harbors a remarkable richness that deserves more attention. Additional studies are essential to better understand the role of AMF in aquatic environments.

COMMITTEE MEMBERS:
Presidente - 1755051 - BRUNO TOMIO GOTO
Externa à Instituição - CAMILA PINHEIRO NOBRE - UEMA
Externo à Instituição - FRANCISCO ADRIANO DE SOUZA - EMBRAPA
Interna - ***.390.185-** - PATRICIA OLIVEIRA FIUZA - UFRN
Interno - ***.924.744-** - RHUDSON HENRIQUE SANTOS FERREIRA DA CRUZ - UFOB