Distefano, Isabel L. , Gardner, Elliot M. , Zerega, Nyree , Clement, Wendy .
Analysis of pollen morphology to predict pollination syndrome in Artocarpus (Moraceae).
Artocarpus (Moraceae) comprises a clade of approximately 70 species of tropical trees that have a center of diversity in Malesia. This group is well-known for its economically important but underutilized tree crops including breadfruit (A. altilis) and jackfruit (A. heterophyllus), but also includes lesser-known crops of great regional importance such as cempedak (A. integer) and terap (A. odoratissimus). Documented accounts of Artocarpus pollination include both wind and biotic syndromes. Previous analyses suggest that wind pollination is ancestral in Moraceae, making Artocarpus an ideal system for studying the evolutionary implications of shifts from wind to biotic pollination. Further, documented cases of insect pollination among Artocarpus involve an unusual tripartite mutualism of dipteran insect pollinators mediated by parasitic fungi that colonize male inflorescences. Identification and study of Artocarpus pollination syndromes would have important evolutionary implications and economical applications; however, detailed studies of pollination across the genus are largely incomplete. Traditional field based studies are slow and challenging for tall rainforests trees and are currently not feasible to perform on all Artocarpus species within a short timeframe. Further, classic morphological signatures of insect pollination, such as showy flowers, are not applicable to Artocarpus species, which – like all Moraceae – have tiny inconspicuous flowers irrespective of pollen vector. The morphological characters of pollen can, however, provide insight into pollination mechanism. We therefore set out to characterize the pollen morphology of Artocarpus through microscopy, digital measurement, and statistical analysis of more than ten pollen characters. Here we present the fullest account to date of the pollen morphology of Artocarpus, with over half of the genus sampled, including representatives of all four Artocarpus subgenera. We analyze the variation in Artocarpus pollen using descriptive statistics and principle component analysis. We compare these data to empirical pollination studies of a few species to test the predictive power of these characters on pollination syndrome. Our results indicate that pollen morphology – especially when combined with additional morphological data – can play an important role in predicting pollination mechanisms in this understudied plant group. Ongoing studies of additional Artocarpus species use targeted field studies to confirm predictions made by morphological analysis of the pollen grains.
1 - The College of New Jersey, Biology, 2000 Pennington Road, Ewing, New Jersey, 08628, United States
2 - Northwestern University / Chicago Botanic Garden, Plant Biology and Conservation, 2205 Tech Drive, 2-144 Hogan Hall, Evanston, IL, 60208, USA
3 - The College Of New Jersey, Biology, 2000 Pennington Road, Department Of Biology, Ewing, NJ, 08638, USA
Presentation Type: Poster:Posters for Topics
Candidate for Awards:None