The use of citric acid (CA) chelator to facilitate metal bioavailability is a promising approach for phytoextraction of heavy metal contaminants. However, the role of CA chelator associated with arbuscular mycorrhizal fungi (AMF) inoculation on phytoextraction of vanadium (V) has not been studied. Therefore, in this study, a greenhouse pot experiment was conducted to evaluate the combined effect of CA chelator and AMF inoculation on plant growth and V phytoextraction in the V mining contaminated soil by Medicago sativa Linn. (M. sativa). The experiment was performed via CA (at 0, 5 and 10 mM kg− 1 soil levels) application alone or in combination with AMF inoculation. Plant biomass, root mycorrhizal colonization, P and V accumulation, antioxidant enzyme activity in plant, and soil chemical speciation of V were evaluated. Results depicted (1) a marked decline in plant biomass and root mycorrhizal colonization in 5- and 10-mM CA treatments which were accompanied by a significant increased V accumulation in M. sativa tissues. The effects could be attributed to the enhancement of bioavailable V by mainly transferring from the reducible to acid-soluble V fraction. (2) The presence of CA significantly enhanced P acquisition while the ratio of P/V concentration in plant shoots and roots decreased, owing to the increased V translocation from soil to plant. (3) In both CA treated soil, AMF symbiosis significantly improved dry weight (31.4–73.3%) and P content (37.3-122.5%) in shoot and root of M. sativa, and showed markedly contribution in reduction of malondialdehyde (MDA) content (12.8–16.2%) and higher antioxidants (SOD, POD and CAT) activities in the leaves, suggesting their combination could promote growth performance and stimulate antioxidant response alleviating V stress induced by CA chelator. (4) Taken together, 10 mM kg− 1 CA application and AMF inoculation combination exhibited higher amount of extracted V both in the shoot and root. Thus, citric acid-AMF-plant symbiosis provides a novel remediation strategy for in situ V phytoextraction by M. sativa in the contaminated soil.

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Posted 22 Feb, 2021
Invitations sent on 19 Feb, 2021
Received 19 Feb, 2021
On 21 Jan, 2021
Posted 22 Feb, 2021
Invitations sent on 19 Feb, 2021
Received 19 Feb, 2021
On 21 Jan, 2021
The use of citric acid (CA) chelator to facilitate metal bioavailability is a promising approach for phytoextraction of heavy metal contaminants. However, the role of CA chelator associated with arbuscular mycorrhizal fungi (AMF) inoculation on phytoextraction of vanadium (V) has not been studied. Therefore, in this study, a greenhouse pot experiment was conducted to evaluate the combined effect of CA chelator and AMF inoculation on plant growth and V phytoextraction in the V mining contaminated soil by Medicago sativa Linn. (M. sativa). The experiment was performed via CA (at 0, 5 and 10 mM kg− 1 soil levels) application alone or in combination with AMF inoculation. Plant biomass, root mycorrhizal colonization, P and V accumulation, antioxidant enzyme activity in plant, and soil chemical speciation of V were evaluated. Results depicted (1) a marked decline in plant biomass and root mycorrhizal colonization in 5- and 10-mM CA treatments which were accompanied by a significant increased V accumulation in M. sativa tissues. The effects could be attributed to the enhancement of bioavailable V by mainly transferring from the reducible to acid-soluble V fraction. (2) The presence of CA significantly enhanced P acquisition while the ratio of P/V concentration in plant shoots and roots decreased, owing to the increased V translocation from soil to plant. (3) In both CA treated soil, AMF symbiosis significantly improved dry weight (31.4–73.3%) and P content (37.3-122.5%) in shoot and root of M. sativa, and showed markedly contribution in reduction of malondialdehyde (MDA) content (12.8–16.2%) and higher antioxidants (SOD, POD and CAT) activities in the leaves, suggesting their combination could promote growth performance and stimulate antioxidant response alleviating V stress induced by CA chelator. (4) Taken together, 10 mM kg− 1 CA application and AMF inoculation combination exhibited higher amount of extracted V both in the shoot and root. Thus, citric acid-AMF-plant symbiosis provides a novel remediation strategy for in situ V phytoextraction by M. sativa in the contaminated soil.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6
This is a list of supplementary files associated with this preprint. Click to download.
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