Trocas gasosas e crescimento inicial de clones de eucalipto em diferentes condições térmicas e hídricas

• Autor(a) principal: Fonseca, Mariana Duarte Silva
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/11084
• topic: Thermal amplitude; Biomass; Water stress; Thermal stress; Amplitude térmica; Biomassa; Estresse hídrico; Estresse térmico; Recursos Florestais e Engenharia Florestal; 630

The temperature and water availability of the soil are crucial factors for establishing the plants. The variation of temperature during the day the water availability of the soil influence the gas exchange and the initial plants growth, especially of eucalyptus plantations. This study aimed to analyze the gas exchange and initial growth of clonal eucalyptus seedlings submitted to different thermal regimes and water. Two experiments were carried out in climatized greenhouses for simulating different environments. The first one had as objective to analyze gas exchange and the initial growth of six eucalyptus clones submitted to environments with different thermal regimes. As a result, clone AEC 1528 showed better biomass production in warmer environments, above 19.9 °C average temperature; GG157 and GG100 clones require an average temperature of 21.4 °C; the AEC 144 was tolerant to all thermal regimes studied; average temperature of 24.8 °C and lower daily thermal amplitude benefited the production of CNB 001, while average intermediate temperatures (21.4 and 24.8 °C) were the best for clone CNB 002. Low average temperatures (19.9 °C) decreased the net assimilation rate of the clones. In the second experiment, the plants were submitted to heat waves (36.3, 42.8 and 45.4 ºC) and water deficit. Water deficit caused greater interference in most in gas exchange alterations, dry matter (total, shoot, root) and leaf area than the maximum temperature of the heat wave in both clones. The AEC 144 clone was affected by the water condition, but was indifferent to heat waves. TP-361 clone was affected in the heat wave of 45.4 °C and 47% of substrate water availability. Variations of minimum temperature, maximum, thermal amplitude and water deficit presented direct interference in the gas exchange values and, consequently, biomass production of eucalyptus clones.