Increased seed survival and seedling emergence in a polyploid plant invader
• Premise of the study: Because seeds have essential functions in the life cycle of plants, even subtle changes in their characteristics may have important demographic consequences. In this study, we examined whether potential changes in seed characteristics as a result of polyploidy or postintroduc...
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Published in | American journal of botany Vol. 100; no. 8; pp. 1555 - 1561 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
United States
Botanical Society of America
01.08.2013
Botanical Society of America, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | • Premise of the study: Because seeds have essential functions in the life cycle of plants, even subtle changes in their characteristics may have important demographic consequences. In this study, we examined whether potential changes in seed characteristics as a result of polyploidy or postintroduction evolution may have contributed to the invasion of Centaurea stoebe (Asteraceae). This plant occurs as diploid and tetraploid cytotypes in its native range in Europe, whereas only tetraploids have been found and become invasive in North America. Specific comparisons among these three “geo-cytotypes” allow us to explore hypotheses of preadaptation resulting from polyploidy (European diploids vs. European tetraploids) and postintroduction evolution (European tetraploids vs. North American tetraploids).• Methods: Using seeds collected from plants of each geo-cytotype grown in a common maternal environment, we compared seed mass, morphology (achene and pappus size), dispersal potential (falling velocity, seed roughness), survival, germination, and seedling emergence in a combination of laboratory, greenhouse and field experiments.• Key results: We found increased seed mass in North American tetraploids compared with European tetraploids. Seed morphology and dispersal potential were largely similar in all geo-cytotypes. Seed survival under field conditions was higher in native and invasive tetraploids compared with diploids. Germination in the laboratory was similar among all geo-cytotypes, but seedling emergence under field conditions was higher in invasive tetraploids than in the other geo-cytotypes.• Conclusions: Our findings suggest that a combination of preadaptation due to polyploidy (increased seed survival) and further postintroduction evolution in North American tetraploids (increased seed mass and seedling emergence) may have contributed to their invasion. |
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Bibliography: | http://dx.doi.org/10.3732/ajb.1200540 The authors thank O. Tackenberg for support in determining falling velocity and roughness of seeds; Y. Buckley and P. Mráz for comments on the experimental procedure; A. Hahn for help in graphical transformation of seed images; R. Zindel, W. Hahn, L. Buholzer, S. Müller, D. Crottet, J.‐B. Haas, M. Stokvis, M. Henery, B. Hall, H. Benson, J. Bielanska, and S. Rossinelli for assistance during the field experiment and data collection; and the School of Agriculture in Grangeneuve, Switzerland for providing and maintaining the experimental site. H.M.S. acknowledges funding by the Swiss National Science Foundation (SNSF grant 31003A_125314, and through the National Centre of Competence in Research ‘Plant Survival’). ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 ObjectType-Article-2 ObjectType-Feature-1 |
ISSN: | 0002-9122 1537-2197 |
DOI: | 10.3732/ajb.1200540 |