scholarly journals An Illustration of Biological Nitrogen Fixation for Plant Science Students

1993 ◽  
Vol 3 (4) ◽  
pp. 462-463
Author(s):  
William R. Graves ◽  
Lorna C. Wilkins
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Black Locust ◽  
Robinia Pseudoacacia ◽  
Plant Science ◽  
Science Students ◽  
Laboratory Exercise ◽  
Science Courses ◽  
Biological Nitrogen ◽  
Plastic Containers

A laboratory exercise for illustrating aspects of biological nitrogen fixation (BNP) to students in plant science courses is described. Surface-sterilized seeds of black locust (Robinia pseudoacacia L.) and soybean (Glycine max Merill) were sown together in plastic containers filled with a sterile, soilless medium. Containers were assigned randomly to treatments designed to show how inoculation with two strains of rhizobial bacteria and application of nitrate affect root nodulation and plant growth. Results demonstrated that BNF occurs in diverse legumes, that legumes vary in the strains of rhizobia with which they associate, that nodulation is inhibited by nitrate, and that dependency on BNP can reduce growth compared with plants provided nitrate.

scholarly journals Interaction of Biochar Type and Rhizobia Inoculation Increases the Growth and Biological Nitrogen Fixation of Robinia pseudoacacia Seedlings

Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 711 ◽  
Author(s):  
Qiaoyu Sun ◽  
Yong Liu ◽  
Hongbin Liu ◽  
R. Kasten Dumroese
Keyword(s):  
Nitrogen Fixation ◽  
Seedling Growth ◽  
Biological Nitrogen Fixation ◽  
Robinia Pseudoacacia ◽  
Nodule Development ◽  
Total Biomass ◽  
Greenhouse Study ◽  
Nodule Biomass ◽  
Biological Nitrogen ◽  
Seedling Leaf

Adding biochar to soil can change soil properties and subsequently affect plant growth, but this effect can vary because of different feedstocks and methods (e.g., pyrolysis or gasification) used to create the biochar. Growth and biological nitrogen fixation (BNF) of leguminous plants can be improved with rhizobia inoculation that fosters nodule development. Thus, this factorial greenhouse study examined the effects of two types of biochar (i.e., pyrolysis and gasification) added at a rate of 5% (v:v) to a peat-based growth substrate and rhizobia inoculation (yes or no) on Robinia pseudoacacia (black locust) seedlings supplied with 15NH415NO3. Seedling and nodule growth, nitrogen (N) content, and δ15N × 1000 were evaluated after 3 months. While addition of biochar without inoculation had no effect on seedling growth, inoculation with rhizobia increased seedling growth, BNF, and N status. Inoculated seedlings had reduced δ15N, indicating that N provided via fertilization was being diluted by N additions through BNF. Biochar type and inoculation interacted to affect seedling growth. Combining inoculation with either biochar type increased seedling leaf, stem, and total biomass, whereas gasifier biochar and inoculation improved all seedling growth variables and nodule biomass.

scholarly journals Functional analysis of multiple nifB genes of Paenibacillus strains in synthesis of Mo-, Fe- and V-nitrogenases

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Qin Li ◽  
Haowei Zhang ◽  
Liqun Zhang ◽  
Sanfeng Chen
Keyword(s):  
Functional Analysis ◽  
Nitrogen Fixation ◽  
Gene Cluster ◽  
Biological Nitrogen Fixation ◽  
Deletion Analysis ◽  
Phylogeny Analysis ◽  
Biological Nitrogen

Abstract Background Biological nitrogen fixation is catalyzed by Mo-, V- and Fe-nitrogenases that are encoded by nif, vnf and anf genes, respectively. NifB is the key protein in synthesis of the cofactors of all nitrogenases. Most diazotrophic Paenibacillus strains have only one nifB gene located in a compact nif gene cluster (nifBHDKENX(orf1)hesAnifV). But some Paenibacillus strains have multiple nifB genes and their functions are not known. Results A total of 138 nifB genes are found in the 116 diazotrophic Paenibacillus strains. Phylogeny analysis shows that these nifB genes fall into 4 classes: nifBI class including the genes (named as nifB1 genes) that are the first gene within the compact nif gene cluster, nifBII class including the genes (named as nifB2 genes) that are adjacent to anf or vnf genes, nifBIII class whose members are designated as nifB3 genes and nifBIV class whose members are named as nifB4 genes are scattered on genomes. Functional analysis by complementation of the ∆nifB mutant of P. polymyxa which has only one nifB gene has shown that both nifB1 and nifB2 are active in synthesis of Mo-nitrogenase, while nifB3 and nifB4 genes are not. Deletion analysis also has revealed that nifB1 of Paenibacillus sabinae T27 is involved in synthesis of Mo-nitrogenase, while nifB3 and nifB4 genes are not. Complementation of the P. polymyxa ∆nifBHDK mutant with the four reconstituted operons: nifB1anfHDGK, nifB2anfHDGK, nifB1vnfHDGK and nifB2vnfHDGK, has shown both that nifB1 and nifB2 were able to support synthesis of Fe- or V-nitrogenases. Transcriptional results obtained in the original Paenibacillus strains are consistent with the complementation results. Conclusions The multiple nifB genes of the diazotrophic Paenibacillus strains are divided into 4 classes. The nifB1 located in a compact nif gene cluster (nifBHDKENX(orf1)hesAnifV) and the nifB2 genes being adjacent to nif or anf or vnf genes are active in synthesis of Mo-, Fe and V-nitrogenases, but nifB3 and nifB4 are not. The reconstituted anf system comprising 8 genes (nifBanfHDGK and nifXhesAnifV) and vnf system comprising 10 genes (nifBvnfHDGKEN and nifXhesAnifV) support synthesis of Fe-nitrogenase and V-nitrogenase in Paenibacillus background, respectively.

Sign in / Sign up

Export Citation Format

Share Document