Lee, David , O'Keefe, John , Jestrow, Brett .
Patterns of Autumn Leaf Color Change in New England Plants.
In the past decade, two hypotheses concerning the adaptive significance of autumn leaf color change have been advocated: (1) photoprotection, enhancing nutrient resorption; and (2) apparency, reducing insect egg deposition and future herbivory. Both hypotheses predict patterns of color production during the autumn, and an accurate survey could verify or eliminate such predictions. We have observed such patterns of autumn color change, along with the anatomical distribution of pigments, in a sample of woody (88) and herbaceous (71) species, including annuals/biennials and perennials, in and near the Harvard Forest as well as in the documented collections of the Gardenin the Woods of the New England Wildflower Society in Framingham, MA. After excluding herbs of the Centrospermae (with betalain pigments) and evergreen shrubs, we compared these groups for (1) the percentage of those producing anthocyanins during senescence; (2) the tissue distributions of these pigments; and (3) their association with light preference. Herbs (42 % with anthocyanins) had fewer red senescing species than woody plants (70 % with anthocyanins), and epidermal distribution of anthocyanins was more common among herbs. All plants had a significant association (Spearman Rank) between light preference and anthocyanin production in senescence, although for herbs the association was highly significant (0.002)and for woody plants not significant (0.208). Although the sample was too small for annuals and biennials (15 species), anthocyanin production was strongly associated with late fruiting. Finally, there is a strong influence of phylogeny on color production during the autumn,particularly among woody plants, and certain families (i.e. the Sapindaceae, Fagaceae,Cornaceae, Adoxaceae and Rosaceae) are disproportionately important. These results are consistent with predictions of the photoprotection hypothesis, but do not exclude the apparency hypothesis.
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1 - Florida International University, Department of Biological Sciences, Owa Ehan-167, Modesto Maidique Campus, Miami, Florida, 33199, USA
2 - Harvard University, Harvard Forest, 324 Main Street, Petersham, MA, 01366, USA
3 - Fairchild Tropical Botanic Garden, Center for Tropical Plant Conservation, 11935 Old Cutler Road, Coral Gables, FL, 33156, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Union B/Hyatt
Date: Tuesday, July 10th, 2012
Time: 2:30 PM