Arbuscular mycorrhizal fungi and Eucalyptus species with different levels of water stress tolerance

• Autor(a) principal: Lopes, Bruna Andréia de Bacco
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: http://www.teses.usp.br/teses/disponiveis/11/11140/tde-12092019-163642/
• topic: Eucalyptus; Eucalipto; Micorrizas; Microbiologia do solo; Mycorrhiza; Soil microbiology; Tolerância ao estresse hídrico; Water stress tolerance

Eucalyptus species account for almost 80% of the forests planted in Brazil, which makes silviculture an activity of great importance in the national and international scenario. Despite its adaptability, Eucalyptus is subject to damages caused by climate change, especially the water deficit. Most plants have survival strategies in water deficit situations. Association with mycorrhizal fungi (FM) is one of them, since they increase water and nutrients uptake by the roots. Thus, the main objective of this study was to evaluate the colonization of mycorrhizal fungi in six Eucalyptus species with different levels of drought tolerance: E. brassiana, E. camaldulensis, E. citriodora, E. cloeziana, E. grandis and E. urophylla. Two trials were carried out, one in the field and another in a greenhouse. In the greenhouse, the substrate of the pots were submitted to different levels of water retention, 50, 75 and 100% of the field capacity, for three months. In the field, soil and roots were sampled at two different periods: after the dry period and after the rainy season. The soil samples and fine roots collected from the two experiments were submitted to microbiological and molecular analyses. AMF root colonization was evaluated. The ITS genes were analyzed by quantitative PCR (qPCR) and the fungal community structure by restriction fragment polymorphism (T-RFLP). Among the eucalypt species studied, E. urophylla presented higher colonization in both trials. Soil microbial activity was strongly affected by soil moisture. The fungal community structure did not differ clearly among the treatments. Age of plants and soil moisture seemed to affect the plant species more than levels of water stress tolerance.