Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2017-02-20T17:57:53Z No. of bitstreams: 2 Tese - Carla Eloiza B. C. Seabra.pdf: 1211089 bytes, checksum: 1125d30550099fb430808207eb415619 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2017-02-20T17:58:36Z (GMT) No. of bitstreams: 2 Tese - Carla Eloiza B. C. Seabra.pdf: 1211089 bytes, checksum: 1125d30550099fb430808207eb415619 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2017-02-20T17:59:00Z (GMT) No. of bitstreams: 2 Tese - Carla Eloiza B. C. Seabra.pdf: 1211089 bytes, checksum: 1125d30550099fb430808207eb415619 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-02-20T17:59:00Z (GMT). No. of bitstreams: 2 Tese - Carla Eloiza B. C. Seabra.pdf: 1211089 bytes, checksum: 1125d30550099fb430808207eb415619 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-07-29 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Mahogany (Swietenia macrophylla King) is in high demand world-wide, and is one of Brazil’s most highly valued forestry species. Balsa (Ochroma pyramidale Cav. ex. Lamb.) also has broad usage and great market potential owing to extremely rapid growth rates. Rather than harvesting these increasingly rare timber species from native forests, high density commercial plantings have been established. However, there is little information concerning the nutritional requirements of both species, especially regarding the response to soil phosphorous (P). Phosphorous is expensive in Brazil and over use is associated with adverse environmental consequences. In this study, we examined the effects of four levels of P fertilization (0, 1, 10 and 100 kg ha-1) on biometric and physiological parameters of mahogany and balsa wood seedlings grown in the greenhouse. The response to P was markedly different for the two species. For mahogany, seedling height, seedling diameter, leaf area, leaf weight, stem dry weight, and total dry weight increased at the 100 kg/ha-1 P level. The greatest increase (3- to 5- fold) occurred for leaf area and leaf weight, whereas root dry mass was not influenced by P. Similarly, %N and %P (but not %C) in leaf, stem and root tissue increased with increasing P level, but increased drastically at the 100 kg/ha-1 P treatment. The divalent cations (Ca and Mg) increased in foliar tissue, yet the concentrations of organic acids in xylem fluid declined with increasing P. Leaf macro- and micro-nutrients concentrations were influenced by P treatments, with the exception of Zn and Fe. Leaf, stem and root P utilization efficiency was highest at the 0, 1 or 10 level. Root phosphatase activity was unaffected by P level. By contrast, balsa responded greatly to increasing P concentration, although the most dramatic increase was at 100 kg/ha-1. For example, there was a 9-, 4-, 66-, 25-, 65-, 25- and 32-fold increase for seedling height, seedling diameter, leaf area, leaf dry mass, stem dry mass, root dry mass, and total dry mass, respectively, for the 0 compared to the 100 kg/ha-1 treatment. Leaf, stem and root %N decreased and %P increased with increasing P levels. Macro and micro nutrient levels wereinfluenced by P treatment, with the exception of Mn. The concentrations of organic acids in xylem fluid were altered by P fertilization; and malic, succinic, and lactic acids were highest at the 100 kg/ha-1 treatment. Leaf, stem and root P utilization efficiency increased greatly with increasing P level; however, root phosphatase activity decreased with increasing P levels. The implications of these physiologic data are discussed in relation to management strategies for the culture of mahogany and balsa. / Plantios comerciais de mogno e pau-de-balsa, com maiores relações custo/benefício, podem alavancar o mercado de madeira de espécies nativas, tanto interno quanto externo. Mogno e pau-de-balsa estãoentre as mais valiosas espécies de madeira com diversos usos, sendo ambas economicamente promissoras. Todavia, informações sobre a influência do fósforo (P) na nutrição e desenvolvimento das mesmas são incipientes. Em condições de casa de vegetação, avaliou-se os efeitos de quatro doses de P (0; 1; 10 e 100 kg ha-1) sobre parâmetros biométricos e fisiológicos dessas espécies. Para mogno, as doses crescentes de P elevaram o crescimento da parte aérea, os conteúdos de carbono, nitrogênio, P e, as concentrações foliares de macronutrientes e manganês, e diminuíram a eficiência de utilização de P, as concentrações foliares de boro e cobre e, a concentração dos ácidos orgânicos no fluido do xilema. Não foi verificado efeito sobre o crescimento de raiz, as concentrações foliares de Zn e Fe, e a atividade de fosfatase de raiz. Destaca-se que houve correlação inversa entre a atividade de fosfatase ácida de raiz e o crescimento da parte aérea e, P e N acumulados na planta. Para pau-de-balsa, o aumento das doses de P elevou o crescimento da parte aérea, a eficiência de utilização de P e a concentração de ácidos orgânicos no fluido do xilema. As concentrações foliares de nutrientes foram afetadas de forma variada pela aplicação de doses de P: P, magnésio e cálcio aumentaram e, nitrogênio, potássio, enxofre, boro, zinco e cobre diminuíram. Doses crescentes de P diminuíram a atividade de fosfatase ácida de raiz. Não foi verificado efeito sobre as concentrações foliares de manganês, ferro e do ácido oxálico no fluido no xilema. Em geral, doses crescentes de P melhoram a formação das mudas dessas espécies. Porém, uma adubação equivalente a 100 kg P ha-1 pode causar desequilíbrio de crescimento em mudas de pau-debalsa.