Response of rhizomes of the invasive Hedychium coronarium J. Konig (Zingiberaceae) to different soil moisture conditions

The ability to maintain high competitiveness under a wide range of conditions is common among successful invasive species. The performance of rhizomatous macrophytes in different habitats is closely related to morphological and physiological adaptations in the rhizome system. We investigated the effects of soil moisture conditions on the microstructure of rhizomes of Hedychium coronarium (Zingiberaceae), an aggressive invader of Neotropical riparian sites. We collected rhizome fragments of H. coronarium and soil samples in wet and dry regions of riparian areas dominated by this species in southeastern Brazil. We measured soil moisture content gravimetrically and rhizome fragments were fixed, sectioned, and stained for histological analysis. Only rhizomes from wet regions exhibited aerenchyma, whereas amyloplasts were much more abundant and larger in rhizomes from dry regions than in rhizomes from wet regions. Even though low starch content in wet soils indicates the occurrence of anaerobic metabolism, the presence of aerenchyma may contribute to the typically high performance of H. coronarium in waterlogged soils. Although further studies are needed to assess how responses at the rhizome level affect the competitive ability of H. coronarium, our findings show that they may play a role in the dominance of this species in Neotropical riparian sites.

Automated summary

Successful invasive species often possess the ability to maintain high competitiveness under various conditions, with the performance of rhizomatous macrophytes closely tied to morphological and physiological adaptations in the rhizome system. Research on the rhizome microstructure of the aggressive invader Hedychium coronarium in Neotropical riparian sites shows differences in aerenchyma presence and amyloplast abundance between wet and dry regions, indicating potential adaptations for high performance in waterlogged soils. Further studies are needed to fully understand how these rhizome responses impact the competitive ability of H. coronarium in riparian habitats.