Azolla: A review of its biology and utilization

Wagner, Gregory M.

doi:10.1007/bf02857915

Cited by 250 publications

(186 citation statements)

References 61 publications

Supporting

Mentioning

178

Contrasting

Unclassified

Order By: Relevance

“…These symbionts are located inside a highly specialized cavity in the dorsal leaf lobe of Azolla and provide the fern with fixed organic nitrogen. Through the symbiosis the aquatic fern Azolla is not limited by fixed nitrogen availability (32), thus facilitating rapid growth (33,34). Indeed, analyses of extracts of extant Azolla filiculoides show the presence of 1-(O-hexose)-3,25-hexacosanediol (C 26 HG diol) (I) and its corresponding keto-ol (II) (Table S1), the predominant glycolipids in the order of Nostocaceae (14).…”

Section: Discussionmentioning

confidence: 99%

Fossilized glycolipids reveal past oceanic N ₂ fixation by heterocystous cyanobacteria

Bauersachs

Speelman

Hopmans

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

N 2 -fixing cyanobacteria play an essential role in sustaining primary productivity in contemporary oceans and freshwater systems. However, the significance of N 2 -fixing cyanobacteria in past nitrogen cycling is difficult to establish as their preservation potential is relatively poor and specific biological markers are presently lacking. Heterocystous N 2 -fixing cyanobacteria synthesize unique long-chain glycolipids in the cell envelope covering the heterocyst cell to protect the oxygen-sensitive nitrogenase enzyme. We found that these heterocyst glycolipids are remarkably well preserved in (ancient) lacustrine and marine sediments, unambiguously indicating the (past) presence of N 2 -fixing heterocystous cyanobacteria. Analysis of Pleistocene sediments of the eastern Mediterranean Sea showed that heterocystous cyanobacteria, likely as epiphytes in symbiosis with planktonic diatoms, were particularly abundant during deposition of sapropels. Eocene Arctic Ocean sediments deposited at a time of large Azolla blooms contained glycolipids typical for heterocystous cyanobacteria presently living in symbiosis with the freshwater fern Azolla, indicating that this symbiosis already existed in that time. Our study thus suggests that heterocystous cyanobacteria played a major role in adding "new" fixed nitrogen to surface waters in past stratified oceans.nitrogen fixation | intact polar lipids | cyanobacterial biomarkers | symbiosis | saproprel

show abstract

Section: Discussionmentioning

confidence: 99%

Fossilized glycolipids reveal past oceanic N ₂ fixation by heterocystous cyanobacteria

Bauersachs

Speelman

Hopmans

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…Azolla is a small aquatic fern belonging to Phylum-Pteridophyta, Class Polypodiopsida, Order Salviniales, Family Azollaceae with a monotypic genus (Wagnar 1997;Pabby et al 2003b, c, Pabby et al 2004bSood and Ahluwalia 2009). This fern represents the only example of Pteridophyte harboring symbiotic association with diazotrophic, nitrogen-fixing cyanobacteria, and bacteria residing in leaf (2008) cavities (Sood et al a, b;Sood and Ahluwalia 2009).…”

Section: Azolla-a Better Macrophyte For Phytoremediationmentioning

confidence: 99%

Phytoremediation Potential of Aquatic Macrophyte, Azolla

Sood

Uniyal

Prasanna

et al. 2011

AMBIO

256

123

View full text Add to dashboard Cite

Aquatic macrophytes play an important role in the structural and functional aspects of aquatic ecosystems by altering water movement regimes, providing shelter to fish and aquatic invertebrates, serving as a food source, and altering water quality by regulating oxygen balance, nutrient cycles, and accumulating heavy metals. The ability to hyperaccumulate heavy metals makes them interesting research candidates, especially for the treatment of industrial effluents and sewage waste water. The use of aquatic macrophytes, such as Azolla with hyper accumulating ability is known to be an environmentally friendly option to restore polluted aquatic resources. The present review highlights the phytoaccumulation potential of macrophytes with emphasis on utilization of Azolla as a promising candidate for phytoremediation. The impact of uptake of heavy metals on morphology and metabolic processes of Azolla has also been discussed for a better understanding and utilization of this symbiotic association in the field of phytoremediation.

show abstract

“…It can fix nitrogen by its symbiotic partnership with Anabaena which resides in the dorsal cavity of Azolla fronds; for this reason Azolla has been used as a green manure to improve soil fertility and rice production (Wagner, 1997). It has been reported that Azolla has a high capacity to accumulate heavy metals such as Cd, Cr, Cu, Ni and Zn (Sela et al, 1989), and can be used to remove heavy metals from wastewater (Bennicelli et al, 2004;Arora and Saxena, 2005;Rakhshaee et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Arsenic accumulation by the aquatic fern Azolla: Comparison of arsenate uptake, speciation and efflux by A. caroliniana and A. filiculoides

Zhang

Lin

Zhao

et al. 2008

Environmental Pollution

View full text Add to dashboard Cite

Arsenic accumulation and efflux differ between strains of the aquatic fern Azolla. This study investigates As accumulation and tolerance of the aquatic fern Azolla. Fifty strains of Azolla showed a large variation in As accumulation. The highest-and lowest-accumulating ferns among the 50 strains were chosen for further investigations. Azolla caroliniana accumulated two times more As than Azolla filiculoides owing to a higher influx velocity for arsenate. A. filiculoides was more resistant to external arsenate due to a lower uptake. Both strains showed a similar degree of tolerance to internal As. Arsenate and arsenite were the dominant As species in both Azolla strains, with methlyated As species accounting for <5% of the total As. A. filiculoides had a higher proportion of arsenite than A. caroliniana. Both strains effluxed more arsenate than arsenite, and the amount of As efflux was proportional to the amount of As accumulation. The potential of growing Azolla in paddy fields to reduce As transfer from soil and water to rice should be further evaluated. a r t i c l e i n f o

show abstract

Azolla: A review of its biology and utilization

Cited by 250 publications

References 61 publications

Fossilized glycolipids reveal past oceanic N ₂ fixation by heterocystous cyanobacteria

Fossilized glycolipids reveal past oceanic N ₂ fixation by heterocystous cyanobacteria

Phytoremediation Potential of Aquatic Macrophyte, Azolla

Arsenic accumulation by the aquatic fern Azolla: Comparison of arsenate uptake, speciation and efflux by A. caroliniana and A. filiculoides

Contact Info

Product

Resources

About

Azolla: A review of its biology and utilization

Cited by 250 publications

References 61 publications

Fossilized glycolipids reveal past oceanic N 2 fixation by heterocystous cyanobacteria

Fossilized glycolipids reveal past oceanic N 2 fixation by heterocystous cyanobacteria

Phytoremediation Potential of Aquatic Macrophyte, Azolla

Arsenic accumulation by the aquatic fern Azolla: Comparison of arsenate uptake, speciation and efflux by A. caroliniana and A. filiculoides

Contact Info

Product

Resources

About

Fossilized glycolipids reveal past oceanic N ₂ fixation by heterocystous cyanobacteria

Fossilized glycolipids reveal past oceanic N ₂ fixation by heterocystous cyanobacteria