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Web Ecology An open-access peer-reviewed journal
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Volume 18, issue 2 | Copyright
Web Ecol., 18, 129-141, 2018
https://doi.org/10.5194/we-18-129-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Standard article 07 Sep 2018

Standard article | 07 Sep 2018

Production of synthetic tetraploids as a tool for polyploid research

Mariana Castro1, Sílvia Castro1,2, and João Loureiro1 Mariana Castro et al.
  • 1CFE, Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal
  • 2Botanic Garden of the University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal

Abstract. Polyploidization has been traditionally considered a phenomenon that mediates ecological differentiation; however, the adaptive value of genome duplications has been seldom explored. Natural or synthetic polyploids offer unique opportunities to experimentally quantify the immediate consequences of genome duplications in plant traits that may be involved with ecological differentiation. Jasione maritima is a diploid-tetraploid complex with cytotypes distributed allopatrically in an environmental gradient ideal for exploring the role of genome duplications in the success of polyploid lineages. However, like in numerous other polyploid complexes, neotetraploids of J. maritima have not been found in nature. In this study we developed a methodology to obtain synthetic tetraploids from seeds collected in wild diploid plants of J. maritima. We tested the effect of different colchicine concentrations and seedling ages in survival and polyploidization success of J. maritima seedlings, using flow cytometry to assess ploidy level and considering the population of origin. A methodology to synchronize seed germination was also explored. Synchronization of seed germination was best achieved using a cold treatment of 2 weeks before the transference to a growth chamber. An overall survival rate of 11.5±0.7% and further tetraploid conversion of 35.6±2.9% was obtained using 3-day-old seedlings of J. maritima. Survival rates were variable depending on colchicine treatment (the highest the most lethal) and seedling origin (i.e. population), while conversion rate was similar across these factors and high rates of tetraploid conversion were obtained. Considering that the main constraint was survival to the colchicine treatment, we suggest the use of the lowest colchicine concentration tested, i.e. 0.1% colchicine. The use of older seedlings increased survival rates but, in many cases, compromised a complete tetraploid conversion, generating many diploid-tetraploid mixoploid plants.

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Natural or synthetic neopolyploids offer unique opportunities to quantify the immediate consequences of polyploidy. We developed a protocol based on seedling exposure to colchicine to obtain neotetraploids from wild diploid plants of Jasione maritima, with potential for being used in other species. High rates of tetraploid conversion were obtained, but survival decreased with increasing colchicine concentration. Therefore, low concentrations were ideal for obtaining neotetraploids.
Natural or synthetic neopolyploids offer unique opportunities to quantify the immediate...
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