AB 16:197-202 (2012)  -  DOI: https://doi.org/10.3354/ab00450

Colonization, regeneration potential and growth rates of fragments of the exotic aquatic macrophyte Hydrilla verticillata

Cristiane Akemi Umetsu1, Heloísa Beatriz Antoniazi Evangelista2, Sidinei Magela Thomaz1,2,3,*

1Programa de Pós-graduação em Ecologia de Ambientes Aquáticos Continentais, 2Programa de Pós-graduação em Biologia Comparada and 3Departamento de Biologia e Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura (Nupélia), Universidade Estadual de Maringá, Maringá, Paraná CEP 87020-900, Brazil

ABSTRACT: Hydrilla verticillata is an aquatic macrophyte recently found in the Upper Paraná River floodplain. This species has a high potential to reproduce and disperse to new sites, mainly through stem fragments. In this study, we evaluated the colonization (the ability of roots to develop), regeneration (the ability of lateral shoots to develop) and growth rates of this species using fragments of different lengths that originated from different plant parts. We selected parts with and without apical tips, each 5 and 10 cm long, and the following hypothesis was tested: the fragments with apical tips have greater colonization and regeneration abilities than fragments without apical tips, and these abilities depend on the fragment length. Our results showed that both fragments with and without tips presented the same number and dry weight of roots and shoots and thus did not differ in their colonization or regeneration abilities. The length was important for the colonization ability, as 10 cm fragments produced more roots than 5 cm fragments. The high colonization and regeneration abilities from different fragments coupled with the high growth rates exhibited by H. verticillata may account for its rapid spread in novel habitats and its competitive success over native species. Thus, we suggest that the inadequate management of this species, resulting in the formation of fragments, especially of large lengths, may have important implications with regard to its infestation of new sites.


KEY WORDS: Fragmentation · Exotic species · Non-native species · Aquatic weed


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Cite this article as: Umetsu CA, Evangelista HBA, Thomaz SM (2012) Colonization, regeneration potential and growth rates of fragments of the exotic aquatic macrophyte Hydrilla verticillata. Aquat Biol 16:197-202. https://doi.org/10.3354/ab00450

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