scholarly journals A novel representation of biological nitrogen fixation and competitive dynamics between nitrogen-fixing and non-fixing plants in a land model (GFDL LM4.1-BNF)

2021 ◽  
Vol 18 (13) ◽  
pp. 4143-4183
Author(s):  
Sian Kou-Giesbrecht ◽  
Sergey Malyshev ◽  
Isabel Martínez Cano ◽  
Stephen W. Pacala ◽  
Elena Shevliakova ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Dynamic Response ◽  
Biological Nitrogen Fixation ◽  
Temporal Dynamics ◽  
N Cycling ◽  
Competitive Dynamics ◽  
Forest Site ◽  
N Limitation ◽  
Biological Nitrogen

Abstract. Representing biological nitrogen fixation (BNF) is an important challenge for coupled carbon (C) and nitrogen (N) land models. Initial representations of BNF in land models applied simplified phenomenological relationships. More recent representations of BNF are mechanistic and include the dynamic response of symbiotic BNF to N limitation of plant growth. However, they generally do not include the competitive dynamics between N-fixing and non-fixing plants, which is a key ecological mechanism that determines ecosystem-scale symbiotic BNF. Furthermore, asymbiotic BNF is generally not included in land models. Here, we present LM4.1-BNF, a novel representation of BNF (asymbiotic and symbiotic) and an updated representation of N cycling in the Geophysical Fluid Dynamics Laboratory Land Model 4.1 (LM4.1). LM4.1-BNF incorporates a mechanistic representation of asymbiotic BNF by soil microbes, a representation of the competitive dynamics between N-fixing and non-fixing plants, and distinct asymbiotic and symbiotic BNF temperature responses derived from corresponding observations. LM4.1-BNF makes reasonable estimations of major carbon (C) and N pools and fluxes and their temporal dynamics, in comparison to the previous version of LM4.1 with N cycling (LM3-SNAP) and to previous representations of BNF in land models generally (phenomenological representations and those without competitive dynamics between N-fixing and non-fixing plants and/or asymbiotic BNF) at a temperate forest site. LM4.1-BNF effectively reproduces asymbiotic BNF rate (13 kgNha-1yr-1) in comparison to observations (11 kgNha-1yr-1). LM4.1-BNF effectively reproduces the temporal dynamics of symbiotic BNF rate: LM4.1-BNF simulates a symbiotic BNF pulse in early succession that reaches 73 kgNha-1yr-1 at 15 years and then declines to ∼0 kgNha-1yr-1 at 300 years, similarly to observed symbiotic BNF, which reaches 75 kgNha-1yr-1 at 17 years and then declines to ∼0 kgNha-1yr-1 in late successional forests. As such, LM4.1-BNF can be applied to project the dynamic response of vegetation to N limitation of plant growth and the degree to which this will constrain the terrestrial C sink under elevated atmospheric CO2 concentration and other global change factors.

scholarly journals A novel representation of biological nitrogen fixation and competitive dynamics between nitrogen-fixing and non-fixing plants in a land model (GFDL LM4.1-BNF)

2021 ◽  
Author(s):  
Sian Kou-Giesbrecht ◽  
Sergey Malyshev ◽  
Isabel Martínez Cano ◽  
Stephen W. Pacala ◽  
Elena Shevliakova ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Dynamic Response ◽  
Biological Nitrogen Fixation ◽  
Temporal Dynamics ◽  
N Cycling ◽  
Competitive Dynamics ◽  
Geophysical Fluid Dynamics Laboratory ◽  
N Limitation ◽  
Biological Nitrogen

Abstract. Representing biological nitrogen fixation (BNF) is an important challenge in the incorporation of nitrogen (N) cycling in land models. Initial representations of BNF in land models applied simplified phenomenological relationships. More recent representations of BNF are mechanistic and include the dynamic response of BNF to N limitation of plant growth. However, they generally do not include the competitive dynamics between N-fixing and non-fixing plants, which is a key ecological mechanism that determines ecosystem-scale symbiotic BNF. Furthermore, asymbiotic BNF is generally not included in land models. Here, we present LM4.1-BNF, a novel representation of BNF (asymbiotic and symbiotic) and an updated representation of N cycling in the Geophysical Fluid Dynamics Laboratory Land Model 4.1 (LM4.1). LM4.1-BNF incorporates a mechanistic representation of asymbiotic BNF by soil microbes, a representation of the competitive dynamics between N-fixing and non-fixing plants, and distinct asymbiotic and symbiotic BNF temperature responses derived from corresponding observations. LM4.1-BNF makes reasonable estimations of major carbon (C) and N pools and fluxes and their temporal dynamics, in comparison to the previous version of LM4.1 with N cycling (LM3-SNAP) and to previous representations of BNF in land models generally (phenomenological representations and those without competitive dynamics between N-fixing and non-fixing plants and/or asymbiotic BNF). LM4.1-BNF can be applied to project the dynamic response of vegetation to N limitation of plant growth and the degree to which this will constrain the terrestrial C sink under elevated atmospheric CO2 concentration and other global change factors.

scholarly journals Bradyrhizobium as the Only Rhizobial Inhabitant of Mung Bean (Vigna radiata) Nodules in Tropical Soils: A Strategy Based on Microbiome for Improving Biological Nitrogen Fixation Using Bio-Products

2021 ◽  
Vol 11 ◽  
Author(s):  
Vinício Oliosi Favero ◽  
Rita Hilário Carvalho ◽  
Victória Monteiro Motta ◽  
Ana Beatriz Carneiro Leite ◽  
Marcia Reed Rodrigues Coelho ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Grain Yield ◽  
Bacterial Diversity ◽  
Biological Nitrogen Fixation ◽  
Mung Bean ◽  
Soil Microbial Communities ◽  
Tropical Soils ◽  
Soil Samples ◽  
Biological Nitrogen

The mung bean has a great potential under tropical conditions given its high content of grain protein. Additionally, its ability to benefit from biological nitrogen fixation (BNF) through association with native rhizobia inhabiting nodule microbiome provides most of the nitrogen independence on fertilizers. Soil microbial communities which are influenced by biogeographical factors and soil properties, represent a source of rhizobacteria capable of stimulating plant growth. The objective of this study is to support selection of beneficial bacteria that form positive interactions with mung bean plants cultivated in tropical soils, as part of a seed inoculation program for increasing grain yield based on the BNF and other mechanisms. Two mung bean genotypes (Camaleão and Esmeralda) were cultivated in 10 soil samples. Nodule microbiome was characterized by next-generation sequencing using Illumina MiSeq 16S rRNA. More than 99% of nodule sequences showed similarity with Bradyrhizobium genus, the only rhizobial present in nodules in our study. Higher bacterial diversity of soil samples collected in agribusiness areas (MW_MT-I, II or III) was associated with Esmeralda genotype, while an organic agroecosystem soil sample (SE_RJ-V) showed the highest bacterial diversity independent of genotype. Furthermore, OTUs close to Bradyrhizobium elkanii have dominated in all soil samples, except in the sample from the organic agroecosystem, where just B. japonicum was present. Bacterial community of mung bean nodules is mainly influenced by soil pH, K, Ca, and P. Besides a difference on nodule colonization by OTU sequences close to the Pseudomonas genus regarding the two genotypes was detected too. Although representing a small rate, around 0.1% of the total, Pseudomonas OTUs were only retrieved from nodules of Esmeralda genotype, suggesting a different trait regarding specificity between macro- and micro-symbionts. The microbiome analysis will guide the next steps in the development of an inoculant for mung bean aiming to promote plant growth and grain yield, composed either by an efficient Bradyrhizobium strain on its own or co-inoculated with a Pseudomonas strain. Considering the results achieved, the assessment of microbial ecology parameters is a potent coadjuvant capable to accelerate the inoculant development process and to improve the benefits to the crop by soil microorganisms.

scholarly journals Role of Diazotrophic Bacteria in Biological Nitrogen Fixation and Plant Growth Improvement

2016 ◽  
Vol 49 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Wansik Shin ◽  
Rashedul Islam ◽  
Abitha Benson ◽  
Manoharan Melvin Joe ◽  
Kiyoon Kim ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Biological Nitrogen Fixation ◽  
Diazotrophic Bacteria ◽  
Biological Nitrogen

scholarly journals Diazotrophic Bacteria and their Mechanisms to Interact and Benefit Cereals

2021 ◽  
Author(s):  
Vania Carla Pankievicz ◽  
Fernanda Plucani do Amaral ◽  
Jean-Michael Ane ◽  
Gary Stacey
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Biological Nitrogen Fixation ◽  
Bacterial Colonization ◽  
Plant Growth Promoting Bacteria ◽  
Diazotrophic Bacteria ◽  
Genetic Determinants ◽  
Plant Growth Promoting ◽  
Stimulate Plant Growth ◽  
Biological Nitrogen

Plant growth-promoting bacteria (PGPB) stimulate plant growth through diverse mechanisms. Besides biological nitrogen fixation, diazotrophic PGPB can improve nutrient uptake efficiency from the soil, produce and release phytohormones to the host, and confer resistance against pathogens. The genetic determinants that drive the success of biological nitrogen fixation in non-legume plants are understudied. These determinants include recognition and signaling pathways, bacterial colonization, and genotype specificity between host and bacteria. This review presents recent discoveries of how nitrogen-fixing PGPB interacts with cereals and promotes plant growth. We suggest adopting an experimental model system, such as the Setaria-diazotrophic bacteria association, as a reliable way to better understand the associated mechanisms and, ultimately, increase the use of PGPB inoculants for sustainable agriculture.

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