Abstract
Plants react to changes in light and hydrological conditions in terms of quantity and composition of chloroplastidic pigments, which affects the photosynthetic properties and consequently the accumulation of plant biomass. Thus, the chloroplastidic pigment concentration and chlorophyll a fluorescence of three Amazonian species (Bertholletia excelsa, Carapa guianensis e Dipteryx odorata) were investigated in sun and shade leaves form the tree crown collected during two distinct periods of precipitation (dry and rainy seasons). Pigment contents were determined by spectrophotometry and fluorescence variables were determined using a portable fluorometer. The results demonstrated that the species showed high concentrations of Chl a, Chl b e Chl total during the wet season in relation to the dry season, especially in shade leaves. A higher concentration of carotenoids was found in B. excelsa, when compared with leaves of C. guianensis and D. odorata. In leaves of B. excelsa and D. odorata no significant difference was found in relation to the photochemistry of photosystem II (Fv/Fm) between the wet and dry seasons. In conclusion, the three species react differently to variations in the light and precipitation conditions regarding light capture, aspects that might be considered in the management of forest plantations.
Highlights
Due to human impact, site conditions in plantations are different from those in primary forests, affecting the growth of the planted trees even when species were used (BAUCH et al, 1999)
A higher chlorophyll contents on a fresh weight basis was found in the leaves of all species compared to the drier season
The chlorophyll content in sun leaves increased Chl a, Chl b and Chltotal by 54, 31, and 48 % during the wet season compared with the dry season in leaves of D. odorata (Figure 2), whereas no significant differences were found in chlorophyll content between the wet and the dry season for Bertholletia and Carapa
Summary
Site conditions in plantations are different from those in primary forests, affecting the growth of the planted trees even when species were used (BAUCH et al, 1999). Comparative studies carried out in primary forests and forest plantations in the Amazon showed significant alterations of light conditions as well as water and nutrient supply (SZOTT and PALM, 1996; NARDOTO and BUSTAMANTE, 2003). Information on growth and demands for light, nutrients, and water of tree species selected for reforestation programs is needed for sustainable timber production (BAUCH et al, 1999). Most of the native tree species of the Amazon selected from the primary forest lack information on their physiology and field performance. In plantations established in sites with seasonal climate, a strong spatial and temporal variation in light and hydrological conditions can be expected, which to a certain point explain the differences in plant growth and biomass accumulation between trees grown in plantations and trees grown on natural sites (SCHROTH et al, 2000)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
