Eelgrasses are submerged rhizomatous (but not tuberous) aquatic plants, producing rosettes of long strap-like leaves which can vary in length from a few centimetres to 5.5 metres in deep water. Rooted or anchored in sediment they have no leafy stem; leaves all arise from a basal rosette at the sediment surface. Leaves have many small longitudinal veinlets and cross-septa, from 0.4-1cm wide. Plants form stout rhizomes that extend from the sediments. Numerous roots, up to 40cm long, sprout at each leaf-bearing node on the rhizomes (Greater Wellington Regional Council 2004b). The sexes are on different plants, the male flowers released and free-floating and the female with a spiral peduncle.
Juvenile or sterile specimens may be difficult to distinguish (Warrington 1994).
Rooted submerged species, especially those that yield high biomass, such as some Vallisneria spp. are important in phytoremediation (biological remediation of environmental problems using plants) due to their soil-binding roots, rhizomes and stolons (which help facilitate colonisation by benthic algae, other microbes and invertebrates) (Qian et al. 1999, in Vajpayee et al 2001). A study conducted to evaluate the accumulation and toxicity of chromium (Cr) in V. spiralis found that after one week the plants ameliorated 59% of Cr from tannery effluent (which contains a high level of chromium). A higher level of remediation was obtained when the tannery effluent was diluted; 95% of Cr was removed from 25% effluent. It was concluded that V. spiralis effectively removes chromium by surface absorption or adsorption (incorporating it into its own system or storing it in a bound form). Therefore V. spiralis may be effective in bioremediation of diluted tannery effluent and in restoring contaminated wetlands; however safe disposal of contaminated plants in cemented vaults is recommended (Vajpayee et al. 2001).
Compiler: IUCN/SSC Invasive Species Specialist Group (ISSG) with support from the Terrestrial and Freshwater Biodiversity Information System (TFBIS) Programme (Copyright statement)
Review: Dr. Surrey Jacobs Principal Research Scientist Royal Botanic Gardens Sydney NSW, Australia
Publication date: 2006-10-30
Recommended citation: Global Invasive Species Database (2018) Species profile: Vallisneria spiralis. Downloaded from http://www.iucngisd.org/gisd/species.php?sc=878 on 18-12-2018.