Comparing functional traits of planted Eucalyptus sp. genotypes managed as high tree and coppice

• Autor(a) principal: Costa, Jenickson Rayron da Silva
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/242365
• topic: Silvicultural system; Drought tolerance; Vulnerability to cavitation; Water potential; Pressure-Volume curves; Ponto de perda de turgor; Vulnerabilidade à cavitação; Genótipos de Eucalyptus; Tolerância à seca

In this dissertation, we aimed to evaluate the potential of rapidly measured leaf water relations traits for the phenotyping of drought tolerance across the 21 commercial Eucalyptus genotypes, and subsequently, to compare the drought tolerance of Eucalyptus genotypes managed as high forest and coppice stand. The reason for this hypothesis is that, due to a root system developed from the initial development phase, Eucalyptus genotypes managed as coppice experience less water stress in the first years of the rotation. Therefore, Eucalyptus genotypes managed as coppice are less resistant to drought, due to plasticity in drought tolerance traits. The field experiment was installed in February 2018 in Itatinga, São Paulo state, Brazil. We found that πo and Ψtlp exhibit a significant seasonal plasticity. Only the measurements conducted at the end of the dry season were associated to some extent with the expected drought tolerance of the Eucalyptus genetic materials. Although we confirmed that variation in Ψtlp is mostly driven by variation in πo across Eucalyptus material, the osmometer method was not able to accurately rank drought tolerance among the genotypes of our common-garden experiment. We found that the drought tolerance traits of coppice and high forest are similar. Contrary to expectations, plant drought tolerance predictor traits such as Ψtlp and Ψ50 are not influenced by management in commercial Eucalyptus genotypes. Conversely, the stand biomass, and leaf area index are more determinant for differences between silvicultural systems than drought tolerance traits. However, this warrants further investigation of management effects in conditions of higher water stress, in order to draw a more extensive picture of Eucalyptus vulnerability to drought.