Abstract Detail


Batalla, Martin [1], Wallace, Lisa [2].

Variability of climatic conditions in southern South American Myrtaceae as a potential indictor of polyploidy.

Much of the research within the predominantly South American fleshy-fruited Myrtaceae (Myrteae tribe) has been done in tropical genera, while subtropical and temperate Myrteae tend to be overlooked. This tendency is evident in studies regarding polyploids in Myrteae as only the tropical genera Eugenia and Psidium have been studied extensively. Nevertheless, in these genera polyploids have established under a wider set of climatic conditions compared to their diploid counterparts. Myrcianthes and Myrceugenia are the two most diverse Myrteae genera in southern South America, a subtropical to temperate region; Myrceugenia occurs in southern Chile-western Argentina and in southern Brazil-northeastern Argentina, while Myrcianthes ranges from Uruguay to Central America. My aim was to study the variability of climatic conditions for all Myrceugenia and 10 Myrcianthes species whose distributions are primarily in southern South America, in order to predict which species might be polyploids based on occurrence in a wider climatic space, as has been observed in Eugenia and Psidium. Moreover, using principal component analysis of climatic variables, I tested whether the disjunct regions of these genera also showcased differences in climatic conditions. In Myrcianthes, M. mato, M. pungens, and M. cisplatensis exhibited significantly higher variability of climatic conditions compared to other species in the genus and are predicted to be polyploids, or, in the case of the latter species, contain polyploid individuals as diploidy has already been observed in this species. Furthermore, examination of climatic variables across the disjunct distribution of southern Myrcianthes suggests that the two regions in which species occur (southern Brazil-Uruguay, and northwestern Argentina-Bolivia) are environmentally different from each other. Interestingly, predicted polyploid species seem to occur across this disjunction. No clear prediction for a polyploid species was found within Myrceugenia as no species had a significantly higher variability in climatic conditions compared to congeneric species. The two regions in which Myrceugenia occurs have been found to be climatically different; however, in contrast with Myrcianthes, no species occurs in both regions. This study suggests that polyploidy may be an important characteristic found also in extra-tropical Myrteae and perhaps that polyploids are able to have disjunct distributions while diploids are restricted to a specific region. Ploidy levels should be surveyed across these genera to test the accuracy of my predictions and the hypothesis that polyploids are more likely to have disjunct distributions compared to diploids.

1 - 321 N First St, Unit B, Hampton, VA, 23664, United States
2 - Old Dominion University, Biological Sciences, Mills Godwin Building Rm. 110, Norfolk, VA, 23529, United States

Climatic niches
Climatic variability.

Presentation Type: Oral Paper
Number: BIOG II004
Abstract ID:607
Candidate for Awards:None

Copyright © 2000-2022, Botanical Society of America. All rights reserved