| Abstract Detail
Physiological Section Goodale, Uromi Manage [1], Berlyn, Graeme P. [2], Ashton, Mark S. [3], Tennakoon, Kushan U. [4]. Physiological acclimation of pioneer species to changing light environments. To improve our understanding of how acclimation vary among species of the pioneer guild at the functional level and to provide information to assess the feasibility of using pioneer species for reforestation and restoration, we examined physiological characteristics (light saturated rates of photosynthesis {Amax}, light compensation point, light use efficiency, fluorescence and chlorophyll content index) of six pioneer species (Dillenia triquetra, Macaranga indica, Macaranga peltata, Schumachaeria castaneifolia, Trema orientalis, and Wendlandia bicuspidata). They were grown in controlled environmental shelters at the research station of the Sinharaja World Heritage Site in South West Sri Lanka. For all species, unit-area based Amax increased with the increase in the growth light condition (deep shade, low light, medium light, and high light). Trema orientalis had the highest unit-area based Amax across all light treatments and the lowest values were observed for W. bicuspidata and S. castaneifolia. When plants were subjected to an increase in light level, either deep shade to medium light or low light to high light, the highest Amax was observed for plants that went from deep shade to medium light. All species showed lower Amax values when shifted into a lower light condition from the original growth light condition. The other physiological measurements corroborated these results, indicating that although these species were pioneers they responded with a lesser ability to acclimate when subjected to light increases at the high light end (from low light to high light conditions) compared to light increases at the low light end (deep shade to medium light). Results from this study suggest that even within the pioneer guild the ability to adapt to the changes in light environment can be species-specific and can depend on the severity of the change. Such differences can affect the opportunistic capability of species to exploit environmental changes.
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1 - Yale University, School of Forestry and Environmental Studies, Greeley Memorial Laboratory, 370 Prospect Street, New Haven, CT, 06511, USA
2 - Yale University, School of Forestry and Environmental Studies, Greeley Memorial Laboratory, 370 Prospect Street, New Haven, CT, 06107, USA
3 - Yale University, School of Forestry and Environmental Studies, Marsh Hall, 360 Prospect Street, New Haven, CT, 06107, USA
4 - University of Brunei Darussalam, Department of Biology, Faculty of Science, Jalan Tungku Link,, Gadong, BE 1410, BRUNEI DARUSSALAM.
Keywords:
acclimation
Pioneer Species
Sri Lanka
light saturated photosynthesis
light compensation point
light use efficiency
chlorophyll content index
fluorescence.
Presentation Type: Oral Paper:Papers for Sections
Session: 38
Location: 101/Law
Date: Tuesday, July 29th, 2008
Time: 10:30 AM
Number: 38004
Abstract ID:616 |
