Polyploidy Improves Photosynthesis Regulation within the Ranunculus auricomus Complex (Ranunculaceae)

• Published in: Biology (Basel, Switzerland) Vol. 10; no. 8; p. 811
• Main Authors: Ulum, Fuad Bahrul, Hadacek, Franz, Hörandl, Elvira
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 21.08.2021; MDPI
• Subjects: Adaptation; apomixis; Asexual reproduction; Asexuality; Chloroplasts; Diploids; Efficiency; Environmental stress; Experiments; Flowers & plants; Genomes; Habitats; Kautsky curve; Light; Light effects; light stress; Morphology; OJIP; photochemical quenching; Photoperiods; Photosynthesis; Photosystem II; Ploidy; Polyploidy; quantum yield; Ranunculus auricomus; Seeds; apomixis; non-photochemical quenching; light stress; OJIP; habitat adaptation; Kautsky curve; photochemical quenching; quantum yield
• ISSN: 2079-7737; 2079-7737
• DOI: 10.3390/biology10080811

Polyploidy has substantially contributed to successful plant evolution, and is often connected to a higher resilience to environmental stress. We test the hypothesis that polyploids tolerate light stress better than diploids. The complex comprises diploid (2x), tetraploid (4x), and hexaploid (6x) cytotypes, the former of which occur in shaded habitats and the latter more in open, sun-exposed habitats in Central Europe. In this study, we experimentally explored the effects of ploidy and photoperiod extension on the efficiency of photosystem II in the three cytotypes in climate growth chambers. Quantum yields and various coefficients that can be calculated from light curve, Kautsky curve, and fluorescent transient OJIP experiments provided support for the hypothesis that, in comparison to diploids, the improved regulation of excess light by more efficient photochemical and non-chemical quenching in polyploids might have facilitated the adaptation to unshaded habitats. We suggest how lower stress levels in reproductive tissues of polyploids might have favored asexual reproduction.