Plant Systematics and Evolution

, Volume 303, Issue 4, pp 497–507

Spore abortion index (SAI) as a promising tool of evaluation of spore fitness in ferns: an insight into sexual and apomictic species

Original Article


Ferns reproduce through small and usually haploid spores. The general paradigm states that whereas species produce good shaped spores, hybrids are sterile and form aborted spores. Apomictic fern species represent an unusual case, and it is believed that they produce an unbalanced spore spectrum. Until now, no comprehensive comparison of sexual and apomictic taxa using extensive spore fitness data has been published. Based on a representative data set of 109 plants from 23 fern taxa, we accomplished the first robust analysis of spore fitness using spore abortion index (SAI), the ratio of aborted to all examined spores. One thousand spores were analyzed for each plant. Focusing mainly on two major European fern taxa (Asplenium, Dryopteris), we compared this trait for different fern reproductive types (sexual/apomicts/hybrids) and ploidy levels (diploid versus polyploid). Our results confirmed the general assumption that shows higher SAI for apomictic taxa (18%) when compared to sexual taxa (3%). Furthermore, hybrids are characterized by having almost all spores aborted (99.8%) with the notable exception of pentaploid Dryopteris × critica (93.1%), the hybrid between sexual and apomictic taxa. We found no significant difference in SAI between sexual taxa of various ploidy levels or between sexual taxa of genera Dryopteris and Asplenium. Additionally, we carried out an optimization of the SAI method, outlying important guidelines for the use of this method in the future.


Apomixis Asplenium Dryopteris Ferns Spore abortion percentage 

Supplementary material

606_2016_1386_MOESM1_ESM.pdf (438 kb)
Supplementary material 1 (PDF 437 kb)
606_2016_1386_MOESM2_ESM.pdf (398 kb)
Supplementary material 2 (PDF 398 kb)

Copyright information

© Springer-Verlag Wien 2017

Authors and Affiliations

  1. 1.Department of Botany, Faculty of ScienceUniversity of South BohemiaČeské BudějoviceCzech Republic

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