Nitrogen fixation and growth of Lens culinaris as affected by nickel availability: A pre-requisite for optimization of agromining

Abstract

Low soil fertility in ultramafic soils limits the efficiency of nickel phytoextraction. Developing more efficient cropping systems for agromining can be achieved by the association of a hyperaccumulator with a legume by enhancing soil fertility. However, legume crops can result sensitive to ultramafic soil conditions, including nickel Ni availability. We assessed here whether Lens culinaris is adapted to ultramafic environments by growing on soils displaying a wide range of Ni concentrations and consequently producing functional nodules. The soil was enriched with different Ni concentrations ([Ni]) (0-90 mg Ni kg À1). Natural 15 N abundance was used to assess N 2 fixation (%Ndfa). Biotic parameters were investigated (nodule number, Ni, carbon and nitrogen concentrations, plant biomass. . .). Soil parameters were investigated (total [Ni], DTPA-extractable Ni, C and N concentrations. . .). Most of the physicochemical and biological parameters were significantly affected by the increased soil [Ni]. Nodule numbers per plant was lower under high [Ni] than control (soil without Ni). Nodules lost their capacities to fix N 2 under high Ni addition (90 mg Ni kg À1). For many parameters, there were no significant differences between control and treatments up to 60 mg of Ni kg À1 added to the soil. Lentil is able to grow on a soil containing amounts of Ni-DTPA similar to those generally found in serpentine soils. It could be used in association with a hyperaccumulator plant as a nitrogen provider in order to optimize Ni agromining. 2016 Elsevier B.V. All rights reserved.

Improvement of Ni phytoextraction by Alyssum murale and its rhizosphere microbial activities by applying nitrogen fertilizer

“…Concerning the variation of pH in the rhizosphere of A. murale, the addition of NiSO 4 to the soil induced a significant pH decrease. Similar results were observed by Saad et al (2016) after increasing additions of NiSO 4 to an agricultural topsoil. This drop in pH is probably due to the complexation of Ni 2+ to soil surface sites and to the exchange of Ni 2+ with H + from the soil exchange complex, both processes releasing surface H + ions to soil solution.…”

“…These concentrations were chosen to guarantee both a limited toxicity to the soil microbial community and a sufficient Ni availability for phytoextraction. That is why, values were selected in the concentration range (0 to 90 mg Ni kg À1 supplied as NiSO 4 ) studied by Saad et al (2016) to evaluate the nitrogen fixation and growth of Lens culinaris var. Beluga (Fabaceae), France as affected by nickel availability.…”

Developing Sustainable Agromining Systems in Agricultural Ultramafic Soils for Nickel Recovery

“…Moreover, part of the N fixed is usually transferred to companion plants (Rodrigues et al, 2015). Agromining could benefit from this strategy provided the legume tolerates the metal concentrations present in ultramafic soils (Saad et al, 2016). In a mixed legume-crop cover the rhizosphere microbial communities of this association also differ from those found in mono-cultures and can positively influence nutrient availability and plant uptake (St. Luce et al, 2015;Saad et al, 2017).…”

Different Nitro-Oxidative Response of Odontarrhena lesbiaca Plants from Geographically Separated Habitats to Excess Nickel

“…It has the ability to disrupt general metabolic processes, causing morphological alterations like chlorosis or necrosis on leaves or deformed root tips and decreased root growth (reviewed by [ 2 ]), but Ni is also known to be able to reduce cell walls’ plasticity [ 21 ]. The toxicity of Ni is often connected with its negative effect on ion balance and disruption of membranes’ functionality [ 22 ]. Membrane stability can be compromised by the overproduction of reactive oxygen species (ROS) through the process of lipid peroxidation [ 23 ].…”