Inconsistent expression of the gigas effect in polyploid Oxalis

Area of Science:

• Plant evolutionary biology
• Genomics
• Polyploidy research

Background:

• Whole genome duplication (WGD) is a major driver of plant evolution.
• The gigas effect, an increase in plant trait size, is a known WGD outcome.
• WGD is often associated with increased weediness and polyploid persistence.

Purpose of the Study:

• To investigate the presence and consistency of the gigas effect in the genus Oxalis.
• To determine if the gigas effect contributes to the weediness of Oxalis species.
• To assess the role of WGD in polyploid success at organ and cellular levels.

Main Methods:

• Measured traits in diploid and polyploid accessions of 24 Oxalis species.
• Assessed traits, clonality, and selfing in 20 populations of Oxalis purpurea.
• Determined ploidy levels using flow cytometry.

Main Results:

• Found significant variation in traits; no consistent ploidy-related size differences across Oxalis species.
• Oxalis purpurea polyploids exhibited greater underground biomass and more bulbils than diploids.
• Results suggest WGD may contribute to the weediness of Oxalis purpurea.

Conclusions:

• The gigas effect in Oxalis appears nuanced, potentially temporary, and inconsistently expressed.
• WGD can contribute to short-term lineage success through increased vegetative reproduction.
• The gigas effect's role in polyploid persistence and abundance may be context-dependent.