A comparative analysis was carried out of published methods to assess seed viability using 2,3,5-triphenyltetrazolium chloride (TTC) based assays of seed batches. The tests were carried out on seeds of barley (Hordeum vulgare cv. Optic) as a model. We established that 10% [w/v] trichloroacetic acid (TCA)/methanol is superior to the acetone and methanol-only based methods: allowing the highest recovery of formazan and the lowest background optical density (OD) readings, across seed lots comprising different ratios of viable and dead seeds. The method allowed a linear-model to accurately capture the statistically significant relationship between the quantity of formazan that could be extracted using the method we developed and the seed temperature-response, and seed viability as a function of artificially aged seed lots. Other quality control steps are defined to help ensure the assay is robust and these are reported in a Standard Operating Procedure.
Purpose (1) To assess the biological N fixation (BNF) potential of varieties of faba bean (Vicia faba L.) cropped with or without compost in an experimental field-scale rotation with no recent history of legumes, (2) to enumerate soil populations of Rhizobium leguminosarum sv. viciae (Rlv), and to genetically characterize the nodulating Rlv strains, (3) compare BNF with other sites in Britain. Methods BNF was evaluated from 2012 to 2015 using 15 N natural abundance. Treatments were either PK fertilizer or compost. Soil rhizobial populations were determined using qPCR, the symbiotic rhizobia genotyped (16 S rRNA, nodA and nodD genes), and their BNF capacity assessed ex situ. The reliance of legumes on BNF at other British sites was estimated in a single season, and their nodulating symbionts examined. Results Faba bean obtained most of its N through BNF (>80%) regardless of variety or year. N-accumulation by cvs Babylon and Boxer increased with compost treatment in 2014/2015. Rhizobial populations were c. 105-106Rlv cells g−1 soil regardless of field or treatment. 157 Rlv microsymbionts grouped into two large nodAD clades; one mainly from V. faba, and the other from various legumes. All isolates nodulated, and some performed better than commercial inoculant strains. Conclusions Faba bean can provide most of its nitrogen through BNF and leave economically valuable residual N for subsequent crops. Recent legume cropping in northern Europe is not essential for effective nodulation: rhizobia may persist in a range of farmland locations. Nevertheless, there is the potential to apply elite rhizobial strains as inoculants in some soils.
Lathyrus linifolius L. (Reichard) Bässler (Fabiaceae, bitter vetch) is a nitrogen (N) fixing species. A coloniser of low nutrient (N) soils, it supports biodiversity such as key moth and butterfly species, and its roots are known for their organoleptic and claimed therapeutic properties. Thus, the species has high potential for restoration, conservation, novel cropping and as a model species. The last because of its genetic synteny with important pulse crops. However, regeneration and functional attributes of L. linifolius remain to be characterised. Seeds of L. linifolius were characterised using physical, colorimetric and chemical data. Ultrastructural and functional characterisation of the N-fixing root nodules included immunolabelling with nifH protein antibodies (recognising the N-fixing enzyme, nitrogenase). Endosymbiotic bacteria were isolated from root nodules and characterised phylogenetically using 16S rRNA, nodA and nodD gene sequences. L. linifolius yielded heteromorphic seed of distinct colour classes: green and brown. Seed morphotypes had similar C:N ratios and were equally germinable (ca. 90%) after scarification at differing optimal temperatures (16 and 20 °C). Brown seeds were larger and comprised a larger proportion of the seed batch (69%). L. linifolius root nodules appeared indeterminate in structure, effective (capable of fixing atmospheric N) and having strains very similar to Rhizobium leguminosarum biovar viciae. The findings and rhizobial isolates have potential application for ecological restoration and horticulture using native seeds. Also, the data and rhizobial resources have potential applications in comparative and functional studies with related and socio-economically important crops such as Pisum, Lens and Vicia.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.