Water and nutrient use efficiency of Pinus caribaea var. hondurensis and Pinus taeda

• Ano de defesa: 2022
• Autor(a) principal: Santos, Deborah Rodrigues de Souza
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Abundância isotópica; Dendrochronology; Dendrocronologia; Estresse hídrico; Forest management; Isotopic abundance; Manejo florestal; Water stress
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/11/11150/tde-11102022-153732/

The overarching purpose of this study was to evaluate the water and nutrient use effectiveness of Pinus caribaea var. hondurensis and Pinus taeda. To achieve this, the present study was presented in three chapters. For chapters I and II, the study used Pinus spp. trees, at 13 years, from the Cooperative Program on Pine Research in Brazil (PPPIB) experiment, situated in the municipality of Itatinga, São Paulo. Inventory data and measurements of dendrometer bands were used to assess tree growth of Pinus spp. field-grown under distinct fertilized regimes (fertilized and control treatments). Additionally, forty-eight trees were selected, and four cores per tree at approximately 1.3 m height were collected. In Chapter I, the growth, climate-growth relationships, and intrinsic water use efficiency (WUEi) were assessed by a combined analysis of cross-sectional area increment (CSA), water balance and carbon stable isotope ratio (δ13C). In Chapter II, wood density was analyzed by the non-destructive technique of X-ray densitometry. Also, the annual tree-rings were delimitated and the crossdating between trees was performed. Tree ring width and wood density were analyzed by dendrochronological method and correlated with rainfall and temperature. For Chapter III, a greenhouse experiment was conducted with Pinus caribaea var. hondurensis and Pinus taeda seedlings for three months, under two water conditions (well-watered and water deficit) and two soil K levels (sufficient and high). Plant biomass, nutritional status, leaf isotopic composition (δ13C‰ δ15N‰), leaf water potential (Ψw) and chlorophyll fluorescence were measured. In light of the foregoing, some of the key results were: (Chapter I) fertilizer added to Pinus species affected the natural abundance of 13C, resulting in different responses of WUEi; (Chapter II) the fertilization regime increased the wood production in Pinus caribaea var. hondurensis and increased wood density in Pinus taeda; (Chapter III) the K supply negatively affected plant\'s physiology, and inhibited photosynthesis and growth.