Azolla pinnata

Azolla pinnata
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Division: Polypodiophyta
Class: Polypodiopsida
Order: Salviniales
Family: Salviniaceae
Genus: Azolla
Species:
A. pinnata
Binomial name
Azolla pinnata

Azolla pinnata is a species of fern known by several common names, including mosquitofern,[2] feathered mosquitofern and water velvet. It is native to much of Africa, Asia (Brunei Darussalam, China, India, Japan, Korea, and the Philippines) and parts of Australia. It is an aquatic plant, it is found floating upon the surface of the water. It grows in quiet and slow-moving water bodies because swift currents and waves break up the plant.[3] At maximum growth rate, it can double its biomass in 1.9 days, with most strains attaining such growth within a week under optimal conditions.[4]

A. pinnata is a small fern with a triangular stem measuring up to 2.5 centimeters in length that floats on the water. The stem bears many rounded or angular overlapping leaves each 1 or 2 millimeters long. They are green, blue-green, or dark red in color and coated in tiny hairs, giving them a velvety appearance.[3] The hairs make the top surface of the leaf water-repellent, keeping the plant afloat even after being pushed under.[3] A water body may be coated in a dense layer of the plants, which form a velvety mat that crowds out other plants.[3] The hairlike roots extend out into the water.[3] The leaves contain the cyanobacterium Anabaena azollae, which is a symbiont that fixes nitrogen from the atmosphere that the fern can use.[3][5] This gives the fern the ability to grow in habitats that are low in nitrogen.[5]

The plant reproduces vegetatively when branches break off the main axis, or sexually when sporocarps on the leaves release spores.[6]

It is present in New Zealand as an introduced species and an invasive weed that has crowded out a native relative, Azolla rubra.[3] It is a pest of waterways because its dense mats reduce oxygen in the water.[7] The weevil Stenopelmus rufinasus is used as an agent of biological pest control to manage Azolla filiculoides, and it has been found to attack A. pinnata as well.[8]

Rice farmers sometimes keep this plant in their paddies because it generates valuable nitrogen via its symbiotic cyanobacteria.[3][6] The plant can be grown in wet soil and then plowed under, generating a good amount of nitrogen-rich fertilizer.[9] The plant has the ability to absorb a certain amount of heavy metal pollution, such as lead, from contaminated water.[10] It is 25-30% protein and can be added to chicken feed.[11][12]

  1. ^ Gupta, A.K.; Beentje, H.J. (2018). "Azolla pinnata". IUCN Red List of Threatened Species. 2018: e.T168790A120142955. doi:10.2305/IUCN.UK.2018-2.RLTS.T168790A120142955.en. Retrieved 25 March 2024.
  2. ^ English Names for Korean Native Plants (PDF). Pocheon: Korea National Arboretum. 2015. p. 371. ISBN 978-89-97450-98-5. Archived from the original (PDF) on 25 May 2017. Retrieved 26 January 2017 – via Korea Forest Service.
  3. ^ a b c d e f g h Pacific Island Ecosystems at Risk
  4. ^ Watanabe, Iwao; Berja, Nilda S. (1983). "The growth of four species of Azolla as affected by temperature". Aquatic Botany. 15 (2): 175–185. Bibcode:1983AqBot..15..175W. doi:10.1016/0304-3770(83)90027-x. ISSN 0304-3770.
  5. ^ a b Sood, A., et al. (2005). Indicators of phosphorus deficiency in Azolla pinnata (Salviniales, Pteridophyta). Acta Botanica Hungarica 47:1-2 197.
  6. ^ a b Azolla pinnata. Nonindigenous Aquatic Species. USGS
  7. ^ Azolla pinnata. Archived July 10, 2011, at the Wayback Machine Idaho Agriculture.
  8. ^ Pemberton, R. W. and J. M. Bodle. (2009). Native North American Azolla Weevil, Stenopelmus rufinasus (Coleoptera: Curculionidae), uses the invasive old world Azolla pinnata as a host plant. Archived 2010-05-28 at the Wayback Machine Florida Entomologist 92:1 153.
  9. ^ Kaur, H. Biomass production of Azolla pinnata R. Br. in contaminated soils of Punjab (India).[permanent dead link]
  10. ^ Jain, S. K. (1990).Azolla pinnata R.Br. and Lemna minor L. for removal of lead and zinc from polluted water. Water Research 24:2 177-83.
  11. ^ Basak, B., et al. (2002). Azolla (Azolla pinnata) as a feed ingredient in broiler ration. Archived 2011-07-27 at the Wayback Machine International Journal of Poultry Science 1:1 29.
  12. ^ Alalade, O. A. and E. A. Iyayi. (2006). Chemical composition and the feeding value of azolla (Azolla pinnata) meal for egg-type chicks. International Journal of Poultry Science 5:2 137.