Root foraging in the leguminous zinc hyperaccumulator Crotalaria novae-hollandiae from Queensland, Australia

Context Root foraging by hyperaccumulator plants in response to patchily distributed metals has been observed several obligate hyperaccumulators, but it is not known whether facultative hyperaccumulators respond similarly. Aims This study investigated the root-growth behaviour leguminous zinc (Zn) Crotalaria novae-hollandiae compared with non-accumulating cunninghamii localised soil Zn enrichment observe versus avoidance responses. Methods We conducted rhizotron experiments which we exposed species pair juxtaposed treatments, were either homogenous (each half of treatments containing same concentrations) or heterogenous (different concentrations each treatments). The 0 μg g−1 (control), 2000 and 5000 form carbonate). Key results found that none had significantly different rooting density root biomass, regardless species. finding contrasts increased proliferation Zn-rich patches for other Conclusions implications no-preference towards may partly explain hyperaccumulation mechanism displayed these ultimately affect phytoextraction efficacy when utilising a substrate. These findings highlight need rhizosphere investigations prior field applications.