Endoreduplication as a part of flower ontogeny in Trifolium pratense cultivars.

Valéria Kocová,Vladislav Kolarčik,Nikola Straková,Albert Rákai,Pavol Mártonfi

doi:10.1186/s40529-016-0150-x

Valéria Kocová, Vladislav Kolarčik + Show 3 more

Open Access

https://doi.org/10.1186/s40529-016-0150-x

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Abstract

BackgroundEndoreduplication appears in numerous plant species and plays a vital role during ontogeny. The presence of polyploid cells in an otherwise diploid organism is tied specifically to the taxonomy, ecology and physiology of the studied specimen. Little is known about the changes in endopolyploidy levels of floral organs during their development. In order to uncover the workings of endoreduplication in polysomatic species, our study examines flowers of T. pratense in three ontogenetic stages by means of flow cytometry.ResultsCultivar ‘Manuela’ is characterized by the presence of 2C–8C and ‘Dajana’ 2C–16C nuclei. In general, the frequencies of nuclei only slightly changed during development. Endopolyploidy levels represented by endoreduplication index (EI) in the ‘Manuela’ sepals and stamens showed statistical differences between young and old stages, other organs of both cultivars between stages are not statistically different. Significant differences between ‘Manuela’ and ‘Dajana’ cultivars were found only in sepals of I. stage, and in petals and carpels of III. stage. Cultivars showed a similar pattern of endopolyploidy. However, a considerable decrease in EI ‘Manuela’ petals and carpels at III. stage was detected as opposed to ‘Dajana’. Overall, a higher endoreduplication index is distinctive for organs of the ‘Dajana’ cultivar.ConclusionsIn this study we prove the permanent presence of endopolyploid cells in the floral organs of T. pratense throughout their development.

Highlights

Endoreduplication appears in numerous plant species and plays a vital role during ontogeny
Mixoploidy was found in each measured sample of all investigated floral organs (Fig. 3), ranging from 2C + 4C to 2C − 8C nuclei in ‘Manuela’ and from 2C + 4C to 2C − 16C nuclei in ‘Dajana’
The proportion of nuclei of particular ploidy levels differs among floral organs in both cultivars

Summary

Introduction

Endoreduplication appears in numerous plant species and plays a vital role during ontogeny. In order to uncover the workings of endoreduplication in polysomatic species, our study examines flowers of T. pratense in three ontogenetic stages by means of flow cytometry. The phenomenon of endopolyploidy is very common in eukaryotic organisms and is distributed across the whole plant kingdom (Barow 2006). Under certain conditions this process causes a cell to switch from the mitotic to the endoreduplication cycle (Carvalheira 2000; Joubés and Chevalier 2000; Barow and Meister 2003; Leitch et al 2013). Endoreduplication is characterized by the lack of M-phase of the cell cycle leading to several repeated rounds of DNA synthesis. The true biological significance of this phenomenon is not yet fully understood

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