Data/hora: 09/06/2024 12:48:04

Provedor de dados: | Revista Brasileira de Botânica
País: | Brazil
Título: | Photosynthesis and carbon gain under contrasting light levels in seedlings of a pioneer and a climax tree from a Brazilian Semideciduous Tropical Forest
Autores: | Silvestrini,Milene; Válio,Ivany Ferraz Marques; Mattos,Eduardo Arcoverde de.
Data: | 2007-09-01
Ano: | 2007
Palavras-chave: | CO2 assimilation; Growth response to light; Hymenaea courbaril; Photoinhibition; Trema micrantha.
Resumo: | In this study we evaluated photosynthetic characteristics and patterns of biomass accumulation in seedlings of two tree species from a Semideciduous Tropical Forest of Brazil. Seedlings of Trema micrantha (L.) Blum. (pioneer) and Hymenaea courbaril (L.) var. stilbocarpa (Hayne) Lee &amp;amp; Langenh. (climax) were grown for 4 months under low light (LL) (5%-8% of sunlight) and high light (HL) (100% of sunlight). Under HL, T. micrantha showed higher CO2 assimilation rates (A CO2) and light saturation than H. courbaril. Under LL, A CO2 were higher in H. courbaril. Under LL, total chlorophyll and carotenoid contents per unit leaf area were higher in H. courbaril. Chlorophyll a/b ratio was higher in T. micrantha under both light regimes. A CO2 and Fv/Fm ratio at both pre-dawn and midday in H. coubaril were lower in HL indicating chronic photoinhibition. Thus, the climax species was more susceptible to photoinhibition than the pioneer. However, H. courbaril produced higher total biomass under both treatments showing high efficiency in the maintenance of a positive carbon balance. Thus, both species expressed characteristics that favor growth under conditions that resemble their natural microenvironments, but H. courbaril also grew under HL. The ecophysiological range of responses to contrasting light levels of this climax plant seems to be broader than generally observed for other rainforest climax species. We propose that this could be related to the particular spatio-temporal light regime of the semideciduous forests.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042007000300011
Editor: | Sociedade Botânica de São Paulo
Relação: | 10.1590/S0100-84042007000300011
Formato: | text/html
Fonte: | Brazilian Journal of Botany  v.30 n.3 2007
Fonte: | info:eu-repo/semantics/openAccess