Experimental design to assess integrated phytoremediation approach

The use of native hyperaccumulator plant species and the related rhizobiota for phytoremediation allows improving the metal uptake by the root system and increasing the phytoextraction of metals (Rosatto et al. 2019). The goal of the study is to standardize an integrated phytoremediation approach to be used in joint bioremediation protocols (plant-rhizobiota). The experimental design and testing in mesocosm of the Nickel-hyperaccumulator species Alyssoides utriculata (L.) Medik., and Noccaea caerulescens (J. & C. Presl.) F.K. Mey. is presented. The metalliferous soil was sampled in the Ophiolithic Massif of the Voltri Group (Sassello, GE) where total Ni is 1600-2500 mg kg-1 (Marescotti et al. 2019). Selected bacterial and fungal strains have been isolated, screened and consisted of Trichoderma harzianum Rifai group ‘Serp05S’ and Pseudomonas sp. ‘SERP1’ (Rosatto et al. 2019). For each plant species, 5 experimental groups were prepared in pot containing approx. 2.5 L of soil: 1) ‘Control’ (native soil used as is), 2) 'Dry': (dried at 60 °C); 3) ‘Fungi’ (sterilized at 130 °C and inoculated with T. harzianum ‘Serp05S’), 4) ‘Bacteria’ (sterilized at 130 °C and inoculated with Pseudomonas sp. ‘SERP1’), 5) Mix (sterilized at 130 °C and co-inoculated with T. harzianum ‘Serp05S’ and Pseudomonas sp. ‘SERP1’). The experimental design consisted of 5 pot groups randomized in 3 rows for both species, to obtain replicates of each group assuring the inferential statistical processing. Before sowing, soils were monitored pre- and post-inoculation of selected bacterial and fungal strains to assess any possible microbial interaction and succession.