Abstract Detail

Ecology

Yan, Xue Qi [1], Dickinson, Tim [2].

Geographic parthenogenesis: what do allopolyploids get from their parents?

In geographic parthenogenesis (GP) in plants, apomictic allopolyploids may occupy larger ranges and possibly more varied environments than do outcrossing diploid sister taxa. We have examined leaf architecture in relation to range and environmental amplitude in black-fruited Crataegus series Cerrones (section Douglasia) of the central Rocky Mountains and the adjacent Great Basin. This small agamic complex comprises diploid C. saligna Greene and tetraploids C. rivularis Nutt. and C. erythropoda Ashe. Examination of plastid DNA sequence variation and ITS haplotype diversity in these and other hawthorns has shown that this agamic complex also includes the continentally distributed red-fruited tetraploids C. chrysocarpa Ashe (section Coccineae) and C. macracantha Lodd. ex. Loud. (section Macracanthae) as pollen parents of the Cerrones tetraploids. Leaf architecture has been characterized in terms of leaf area, major vein density, minor vein density, serration density, and the inverse of the dissection index. For each of these five species we sampled leaves from three to five specimens collected from across the range of each species. Leaves were cleared and stained, and measured using ImageJ and FIJI. Values of the Bioclim environmental variables were obtained for all of the specimen collection localities. Sexually reproducing C. saligna has small fruits, small leaves with densely arranged major and minor veins, and a range more limited than those of all the other species except C. erythropoda. The apomictic red-fruited tetraploids have large fruits, leaves with less densely arranged veins, and the largest ranges of any North American hawthorn species. The apomictic Cerrones allotetraploids are intermediate in fruit morphology and leaf traits. The range of C. rivularis is more extensive than that of C. saligna and of C. erythropoda, and smaller than the ranges of C. chrysocarpa and C. macracantha. All three Cerrones species share approximately the same subsets of the climatic niches of the two red-fruited species. Hybridization between C. saligna and one or both of the red-fruited species conferred on the hybrids (1) apomixis and the breakdown of gametophytic self-incompatibility; (2) intermediate leaf venation characteristics; and (3) fruits that are intermediate in size. In C. series Cerrones it appears that GP is due to (1) and (3) rather than adaptive features of leaf architecture.

Related Links:
North American black-fruited hawthorns

1 - University of Toronto, Ecology & Evolutionary Biology, 25 Willcocks St., Toronto, ON, M5S 3B2, Canada
2 - Royal Ontario Museum, Natural History, 100 Queen's Park, Toronto, ON, M5S 2C6, Canada

Keywords:
Crataegus
Maleae
Rosaceae
hybridization
gametophytic apomixis.

Presentation Type: Poster
Session: P, Ecology Section Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PEC022
Abstract ID:581
Candidate for Awards:None