Azolla
Contents
Description
Azolla is a genus of small floating ferns with a unique relationship with the nitrogen-fixing bacteria Anabaena azollae. This symbiotic relationship allows the fern to grow rapidly in nitrogen-deficient water, making it an important plant in rice paddies and other agricultural settings.The fern has tiny, overlapping leaves that form a dense mat on the surface of the water. The leaves are green or reddish in color, depending on the species, and have a velvety texture. Azolla also produces small, inconspicuous spore-bearing structures, and can reproduce both sexually and asexually.
Taxonomic Information
| Domain | Eukarya |
|---|---|
| Kingdom | Plantae |
| Phylum | Pteridophyta |
| Class | Polypodiopsida |
| Order | Salviniales |
| Family | Azollaceae |
| Genus | Azolla |
Appearance
Azolla has tiny, overlapping leaves that form a dense mat on the surface of the water. The leaves are typically less than one centimeter in length and have a velvety texture. The fern can be green or reddish in color, depending on the species. When conditions are optimal, azolla can grow rapidly, doubling in biomass in just a few days.
Care Guide
Azolla requires very little care, making it an easy plant to grow. It thrives in still or slow-moving water and can tolerate a wide range of temperatures. However, the following factors can impact its growth:- Water: Azolla needs to be grown in water that is at least 10 cm deep. It also prefers still or slow-moving water, as strong currents can damage the delicate leaves.- Fertilization: Because azolla has a unique relationship with nitrogen-fixing bacteria, it does not require additional fertilization.- Soil: Azolla grows on the surface of the water and does not require soil. However, it can benefit from the addition of organic matter to the water.- Sunlight: Azolla prefers bright, indirect light but can tolerate some shade.- Hardiness Zones: Azolla can be grown in hardiness zones 6-11.
Common Pests & Diseases
Azolla is relatively pest and disease-free. However, it can be susceptible to damage from snails, which can eat the delicate leaves. To prevent snail damage, it is important to maintain healthy water conditions and avoid overfeeding fish or other aquatic animals that may attract snails.
Habitat
Azolla is found in a wide range of habitats, from freshwater ponds and lakes to rice paddies and other agricultural settings. It is native to tropical and subtropical regions of the world, but has been introduced to other areas as an ornamental plant or for use in agriculture.
Question and Answer
Q: Can azolla be grown in a fish tank?
A: Yes, azolla can be grown in a fish tank. It can help to improve water quality by absorbing excess nutrients and providing oxygen.
Q: How often should azolla be fertilized?
A: Because azolla has a unique relationship with nitrogen-fixing bacteria, it does not require additional fertilization.
Q: Does azolla require soil?
A: No, azolla grows on the surface of the water and does not require soil.
Q: Is azolla invasive?
A: Azolla can be considered invasive in some areas, as it can grow rapidly and form dense mats that can displace native plant species.
Related Plants
Other plants in the family Azollaceae include:- Azolla caroliniana- Azolla cristata- Azolla filiculoides- Azolla mexicana- Azolla microphylla
References
– Wagner, W. H. Jr, & Wagner, F. S. (1993). Azolla: A review of its biology and utilization. Botanical Review, 59(1), 1-31.- Xu, Y., & Charles, D. F. (2005). The ecology of azolla and its use as a biological fertilizer. In Water Encyclopedia (pp. 147-150). Wiley.
