Aquatic microphylla Azolla: a perspective paradigm for sustainable agriculture, environment and global climate change

Kollah, Bharati; Patra, A. K.; Mohanty, Santosh Ranjan

doi:10.1007/s11356-015-5857-9

Cited by 108 publications

(73 citation statements)

References 67 publications

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“…Even though chemical N fertilizers have substituted the role of azolla as a green manure, azolla is still cultivated by organic farmers, especially in rice-fish-azolla or rice-duck-azolla multiple eco-production systems in China and Japan (Cheng et al 2015a, b). Additionally, azolla is recognized to modify the physical, chemical, and biological properties of soil and the soil-water interface between flooding water and soil surface in rice fields for mobilizing fixed phosphates, retarding NH 3 volatilization which accompanies the application of chemical N fertilizer, suppressing aquatic weeds in flooding rice field, and reducing evapotranspiration losses for rice production (Mandal et al 1999;Cissé and Vlek 2003;Cheng et al 2015a;Kimani et al 2016;Kollah et al 2016). Recently, azolla has been highlighted again for biofetilizer and biodiesel production (Bocchi and Malgioglio 2010;Jumadi et al 2014;Brouwer et al 2016;Kollah et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Azolla cover significantly decreased CH₄but not N₂O emissions from flooding rice paddy to atmosphere

Kimani

Cheng

Kanno

et al. 2017

Soil Science and Plant Nutrition

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Azolla (Azolla filiculoides) is a common aquatic fern that has been used successfully as a dual crop with lowland rice. It grows rapidly and has the ability to fix N 2 for rice paddy. However, its ecological significance especially on greenhouse gases emissions remains unclear. To investigate the effect of azolla cover on methane (CH 4 ) and nitrous oxide (N 2 O) emissions from rice paddy, a pot experiment with two treatments, control (rice plant only) and azolla cover (rice plus azolla covering on the flooding water), was carried out in Tsuruoka, Yamagata, Japan, in 2016. The results showed that the rice growth parameters, like shoot height, maximum and productive tiller numbers, and plant biomass were not significantly different between the two treatments. Dual cropping of azolla with rice significantly suppressed CH 4 emissions, likely due to an increase in dissolved oxygen concentration and redox potential at the soil-water interface between flooding water and soil surface. There were significant (P < 0.05) positive correlations between CH 4 flux and night respiration (CO 2 emissions) between the two treatments. The cumulated CH 4 emissions during the growth period until 106 days after transplanting (DAT) was significantly lower at 36.2 g C m −2 from azolla cover treatment than that from control treatment pot at 55.4 g C m −2 . A prolonged nonsignificant N 2 O emission under the azolla cover treatment after the initial highest peak at 15 DAT was recorded due to denitrification of the nitrate in initial soil. No further N 2 O emissions were recorded thereafter from both treatments. Azolla cover did not affect N 2 O emissions from both treatments. ARTICLE HISTORY

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Section: Introductionmentioning

confidence: 99%

Azolla cover significantly decreased CH₄but not N₂O emissions from flooding rice paddy to atmosphere

Kimani

Cheng

Kanno

et al. 2017

Soil Science and Plant Nutrition

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“…Finally, the use of synthetic nitrogen fertilizers potentiates the denitrification of nitrogen compounds, which leads to the emission of nitrous oxide as a by-product. Therefore, it is necessary to reduce the effect of agriculture on climate change by promoting the use of biological alternatives to nitrogen fertilizers (biofertilizers), i.e., bacterial/cyanobacterial organisms that possess the remarkable ability to fix nitrogen gas and to furnish the nitrogen requirements of plants [3]. Nitrogen fixation is biologically viable, does not pollute or emit greenhouse gases, and is cost effective and user friendly, which makes this biological process a potent player in mitigating future climate change.…”

Section: Introductionmentioning

confidence: 99%

“…Nitrogen fixation is biologically viable, does not pollute or emit greenhouse gases, and is cost effective and user friendly, which makes this biological process a potent player in mitigating future climate change. Notably, among such alternative solutions is a plant, the aquatic fern Azolla sp., that can act as a biofertilizer by the fortification of a plant biological system with a nitrogen-fixing cyanobiont that churns out ammonia in abundance [3].…”

Section: Introductionmentioning

confidence: 99%

“…in irrigated lands. Urea has been shown to drastically improve nitrous oxide production while being a lesser candidate for the emission of methane; however, it increases the carbon dioxide footprint, which means that using biofertilizers as surrogates to urea diminishes climate change in three combined mechanisms [3,7]. At an ambient CO 2 concentration of 800 ppm, Azolla spp., in a small-scale production system, showed a strong increase in biomass production, i.e., 36-47%, which establishes the potential of Azolla spp.…”

Section: Introductionmentioning

confidence: 99%

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An Exploration of Common Greenhouse Gas Emissions by the Cyanobiont of the Azolla–Nostoc Symbiosis and Clues as to Nod Factors in Cyanobacteria

Gunawardana

2019

Plants

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Azolla is a genus of aquatic ferns that engages in a unique symbiosis with a cyanobiont that is resistant to cultivation. Azolla spp. are earmarked as a possible candidate to mitigate greenhouse gases, in particular, carbon dioxide. That opinion is underlined here in this paper to show the broader impact of Azolla spp. on greenhouse gas mitigation by revealing the enzyme catalogue in the Nostoc cyanobiont to be a poor contributor to climate change. First, regarding carbon assimilation, it was inferred that the carboxylation activity of the Rubisco enzyme of Azolla plants is able to quench carbon dioxide on par with other C3 plants and fellow aquatic free-floating macrophytes, with the cyanobiont contributing on average ~18% of the carboxylation load. Additionally, the author demonstrates here, using bioinformatics and past literature, that the Nostoc cyanobiont of Azolla does not contain nitric oxide reductase, a key enzyme that emanates nitrous oxide. In fact, all Nostoc species, both symbiotic and nonsymbiotic, are deficient in nitric oxide reductases. Furthermore, the Azolla cyanobiont is negative for methanogenic enzymes that use coenzyme conjugates to emit methane. With the absence of nitrous oxide and methane release, and the potential ability to convert ambient nitrous oxide into nitrogen gas, it is safe to say that the Azolla cyanobiont has a myriad of features that are poor contributors to climate change, which on top of carbon dioxide quenching by the Calvin cycle in Azolla plants, makes it an efficient holistic candidate to be developed as a force for climate change mitigation, especially in irrigated urea-fed rice fields. The author also shows that Nostoc cyanobionts are theoretically capable of Nod factor synthesis, similar to Rhizobia and some Frankia species, which is a new horizon to explore in the future.

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“…Azolla has a special significance between the freshwater plants used in phytoremediation. It is a fast growing species and can double it's biomass in 5 to 10 days (Kollah et al, 2016) and for these reason Azolla is often used in phytoremediation studies (De et al, 2017;Gomes et al, 2018;Kosesakal et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Assessment of the biodegradation capacity of Azolla on polycyclic aromatic hydrocarbons in crude oil

2018

Issue 3

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<p>In this study, the potential use of Azolla filiculoides Lam. for the bioremediative solution to polycyclic aromatic hydrocarbon (PAH) pollution due to crude oil spills in freshwater was investigated. The plants were grown in nitrogen-free Hoagland nutrient solution media containing 0.05%, 0.1%, 0.2%, 0.3%, 0.4% and 0.5% crude oil by volume for 15 days under greenhouse conditions. Relative growth rates of A. filiculoides decreased in the presence of crude oil in a concentration-dependent manner. The probable influence of A. filiculoides on the biodegradation of polycyclic aromatic hydrocarbons was measured by using synchronous UV fluorescence spectroscopy. GC-MS analysis were also carried out to elucidate the behavior of the oil in experimental and control samples. Although 1-2 rings PAHs have not been encountered in control or plant samples, the measured intensity for 3-4 ring PAHs in plant samples was remarkably lower in comparison to the control. Furthermore, these results demonstrated that the predominant efficacy of the A. filiculoides was for 3-4 ring PAHs at the range 0.05 to 0.2% crude oil concentrations. It could be concluded that the bioremediative potential of A. filiculoides for the removal of polycyclic aromatic hydrocarbons strongly depends on the amount of oil in the contaminated water resource. In other words, A. filiculoides could be used more effectively after the removal of excess crude oil in the spilled freshwater areas.</p>

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Aquatic microphylla Azolla: a perspective paradigm for sustainable agriculture, environment and global climate change

Cited by 108 publications

References 67 publications

Azolla cover significantly decreased CH₄but not N₂O emissions from flooding rice paddy to atmosphere

Azolla cover significantly decreased CH₄but not N₂O emissions from flooding rice paddy to atmosphere

An Exploration of Common Greenhouse Gas Emissions by the Cyanobiont of the Azolla–Nostoc Symbiosis and Clues as to Nod Factors in Cyanobacteria

Assessment of the biodegradation capacity of Azolla on polycyclic aromatic hydrocarbons in crude oil

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Aquatic microphylla Azolla: a perspective paradigm for sustainable agriculture, environment and global climate change

Cited by 108 publications

References 67 publications

Azolla cover significantly decreased CH4but not N2O emissions from flooding rice paddy to atmosphere

Azolla cover significantly decreased CH4but not N2O emissions from flooding rice paddy to atmosphere

An Exploration of Common Greenhouse Gas Emissions by the Cyanobiont of the Azolla–Nostoc Symbiosis and Clues as to Nod Factors in Cyanobacteria

Assessment of the biodegradation capacity of Azolla on polycyclic aromatic hydrocarbons in crude oil

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Azolla cover significantly decreased CH₄but not N₂O emissions from flooding rice paddy to atmosphere

Azolla cover significantly decreased CH₄but not N₂O emissions from flooding rice paddy to atmosphere