Paper · 2026 · Discover Sustainability

Effects of PGPR and nitrogen fixing bacteria on growth physiological and metabolic response of cowpea

Aluwani Mutanwa Nelwamondo; Sheku Alfred Kanu; Khayalethu Ntushelo; et al.

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11
verbatim quotes
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citations
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Open access · cc-by-nc-nd

Abstract

The rising costs of oil, geopolitics, and frequent climatic events contribute to the scarcity and rising cost of inorganic fertilisers which leads to their unaffordability by poor-resourced farmers. There is a need to assess alternative inputs that are accessible, affordable and sustainable. Such alternative includes the application of biofertilizers as they are biological remedies that have been proven to promote sustainable production, especially food legume crops. In this study, we assessed whether co-inoculation of cowpea with Bradyrhizobium japonicum and Bacillus subtilis (strain BD233) could alter its growth and physiological performance when grown in a naturally lit glasshouse. The experiment was carried out in a completely randomized design (CRD) with four treatments replicates 12 times. The treatments entailed Bradyrhizobium japonicum and Bacillus subtilis (strain BD233), single inoculation of Bradyrhizobium japonicum, 0.5 mM NO3 as positive control (N source) and uninoculated (untreated). Chlorophyll content and stomatal conductance were determined at the mid-flowering growth stage and yield, biomass and nodulation were determined during the maturity growth stage. Our results showed that when dual inoculation of nitrogen fixing rhizobia and plant growth promoting rhizobacteria resulted in enhanced root fresh and dry weight, nodule number and nodule fresh, number of pods, number of seeds, chlorophyll content, stomatal conductance, and concentration of metabolites. The findings from the study support several of the United Nations Sustainable Development Goals (SDGs) including SDG 2, SGD 12 and SDG 13 which focuses on food and nutrition security, sustainable use of inputs and the resilience of the climate by minimising the need to use synthetic fertilisers. Clearly, dual inoculation of cowpea seeds using the selected bio-inputs is important as a sustainable agronomic approach to enhance growth performance and metabolites contributing to the cost-effective cowpea production.

Abstract from the paper’s OpenAlex record; open copy licensed cc-by-nc-nd. Read at the source ↗

The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.

Claims 6

Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Dual inoculation enhanced root fresh and dry weight.

Treatment
dual inoculation of nitrogen fixing rhizobia and plant growth promoting rhizobacteriae0
Outcome
root fresh and dry weighte0
Direction
enhancede0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Vigna unguiculata
Vigna unguiculata · TaxonHeraldDesa at English Wikipedia · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“when dual inoculation of nitrogen fixing rhizobia and plant growth promoting rhizobacteria resulted in enhanced root fresh and dry weight, nodule number and nodule fresh, number of pods, number of seeds, chlorophyll content, stomatal conductance, and concentration of metabolites.”

✓ located verbatim in the source · abstract, characters 1217–1497 · show in text ↑
t0

“cowpea”

✓ located verbatim in the source · title, characters 95–101 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Dual inoculation enhanced nodule number and nodule fresh weight.

Treatment
dual inoculation of nitrogen fixing rhizobia and plant growth promoting rhizobacteriae0
Outcome
nodule number and nodule freshe0
Direction
enhancede0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Vigna unguiculata
Vigna unguiculata · TaxonHeraldDesa at English Wikipedia · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“dual inoculation of nitrogen fixing rhizobia and plant growth promoting rhizobacteria resulted in enhanced root fresh and dry weight, nodule number and nodule fresh, number of pods, number of seeds, chlorophyll content, stomatal conductance, and concentration of metabolites.”

✓ located verbatim in the source · abstract, characters 1222–1497 · show in text ↑
t0

“cowpea”

✓ located verbatim in the source · title, characters 95–101 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Dual inoculation enhanced pod and seed numbers.

Treatment
dual inoculation of nitrogen fixing rhizobia and plant growth promoting rhizobacteriae0
Outcome
number of pods, number of seedse0
Direction
enhancede0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Vigna unguiculata
Vigna unguiculata · TaxonHeraldDesa at English Wikipedia · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“dual inoculation of nitrogen fixing rhizobia and plant growth promoting rhizobacteria resulted in enhanced root fresh and dry weight, nodule number and nodule fresh, number of pods, number of seeds, chlorophyll content, stomatal conductance, and concentration of metabolites.”

✓ located verbatim in the source · abstract, characters 1222–1497 · show in text ↑
t0

“cowpea”

✓ located verbatim in the source · title, characters 95–101 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Dual inoculation enhanced chlorophyll content and stomatal conductance.

Treatment
dual inoculation of nitrogen fixing rhizobia and plant growth promoting rhizobacteriae0
Outcome
chlorophyll content, stomatal conductancee0
Direction
enhancede0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Vigna unguiculata
Vigna unguiculata · TaxonHeraldDesa at English Wikipedia · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“dual inoculation of nitrogen fixing rhizobia and plant growth promoting rhizobacteria resulted in enhanced root fresh and dry weight, nodule number and nodule fresh, number of pods, number of seeds, chlorophyll content, stomatal conductance, and concentration of metabolites.”

✓ located verbatim in the source · abstract, characters 1222–1497 · show in text ↑
t0

“cowpea”

✓ located verbatim in the source · title, characters 95–101 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Dual inoculation enhanced metabolite concentration.

Treatment
dual inoculation of nitrogen fixing rhizobia and plant growth promoting rhizobacteriae0
Outcome
concentration of metabolitese0
Direction
enhancede0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Vigna unguiculata
Vigna unguiculata · TaxonHeraldDesa at English Wikipedia · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“dual inoculation of nitrogen fixing rhizobia and plant growth promoting rhizobacteria resulted in enhanced root fresh and dry weight, nodule number and nodule fresh, number of pods, number of seeds, chlorophyll content, stomatal conductance, and concentration of metabolites.”

✓ located verbatim in the source · abstract, characters 1222–1497 · show in text ↑
t0

“cowpea”

✓ located verbatim in the source · title, characters 95–101 · show in text ↑
Recommendationauthor interpretationoriginal resultbasis n/a

Claim · model-written summary

The authors recommend dual seed inoculation for cost effective cowpea production.

Outcome
dual inoculation of cowpea seedse0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Vigna unguiculata
Vigna unguiculata · TaxonHeraldDesa at English Wikipedia · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“dual inoculation of cowpea seeds using the selected bio-inputs is important as a sustainable agronomic approach to enhance growth performance and metabolites contributing to the cost-effective cowpea production.”

✓ located verbatim in the source · abstract, characters 1804–2015 · show in text ↑

nitrogen · yield · Vigna unguiculata (cowpea)Results differ

68 papers: 62 positive, 6 negative or no effect

61 papers in the same direction as this paper · 6 in the opposite direction

  1. no effect
  2. negative
  3. no effect

64 papers more in this group

See all 68 papers →

inoculation · symbiosis · Vigna unguiculata (cowpea)Results differ

69 papers: 57 positive, 12 negative or no effect

56 papers in the same direction as this paper · 11 in the opposite direction · 1 reporting no difference from an alternative

  1. positive
  2. no effect
  3. no effect

65 papers more in this group

See all 69 papers →

inoculation · yield · Vigna unguiculata (cowpea)Results differ

116 papers: 99 positive, 17 negative or no effect

98 papers in the same direction as this paper · 16 in the opposite direction · 1 reporting no difference from an alternative

  1. positive
  2. positive
  3. negative

112 papers more in this group

See all 116 papers →

inoculation · physiology: gas exchange · Vigna unguiculata (cowpea)Positive and negative results

4 papers: 3 positive, 1 negative or no effect

2 papers in the same direction as this paper · 1 in the opposite direction

  1. no effect
  2. positive
  3. positive
See all 4 papers →

inoculation · molecular: metabolites · Vigna unguiculata (cowpea)Positive and negative results

15 papers: 14 positive, 1 negative or no effect

13 papers in the same direction as this paper · 1 in the opposite direction

  1. negative
  2. positive
  3. positive

11 papers more in this group

See all 15 papers →

nitrogen · symbiosis · Vigna unguiculata (cowpea)Positive and negative results

17 papers: 13 positive, 4 negative or no effect

12 papers in the same direction as this paper · 4 in the opposite direction

  1. negative
  2. negative
  3. negative

13 papers more in this group

See all 17 papers →

nitrogen · growth · Vigna unguiculata (cowpea)Positive and negative results

45 papers: 39 positive, 6 negative or no effect

38 papers in the same direction as this paper · 6 in the opposite direction

  1. negative
  2. no effect
  3. no effect

41 papers more in this group

See all 45 papers →

inoculation · growth · Vigna unguiculata (cowpea)Positive and negative results

102 papers: 92 positive, 10 negative or no effect

91 papers in the same direction as this paper · 8 in the opposite direction · 2 reporting no difference from an alternative

  1. positive
  2. no effect
  3. negative

98 papers more in this group

See all 102 papers →

8 of 9 groups shown: named compounds and organisms first, then groups whose results differ (checked claim by claim), then those with positive and negative results, then the smaller groups.

Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.