Copper localization in Cannabis sativa grown in a copper-rich solution Piera Bonatti, Laura Arru, Sara Rognoni, Micaela Baroncini, Pierdomenico Perata University of Modena & Reggio Emilia

The use of plants to remove heavy metals and other pollutants from soils and waters PHYTOREMEDIATION

PHYTOEXTRACTION OF HEAVY METALS The most common heavy metals are: Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sn, Zn Are often very toxic to living organisms over a certain concentration threshold

HYPERACCUMULATOR SPECIES Represent <0,2% of all angiosperms ~400 species are hyperaccumulators HYPERACCUMULATION THRESHOLDS: Zn, Mn: mG/KG Co, Cu, Ni, Se: mG/KG Cd: 100 mG/KG These thresholds are 2-3 orders of magnitude higher than in normal plant species WHICH PLANT SPECIES FOR PHYTOEXTRACTION?

Alyssum serpyllifolium Brassica juncea Liriodendron tulipifera Pteris vittata Thlaspi caerulescens HYPERACCUMULATOR SPECIES & PHYTOREMEDIATION PLANTS

Hyperaccumulator species must be hypertolerant to heavy metals WHICH PLANT SPECIES FOR PHYTOEXTRACTION? Pteris vittata accumulates up to mG/KG of arsenic, with no phytotoxicity simptoms up to mG/KG As (Ma et al, Nature, 2001; Wang et al., Plant Physiol., 2002)

Hyperaccumulator species = low biomass? WHICH PLANT SPECIES FOR PHYTOEXTRACTION? Thlaspi caerulescens, a Zn/Cd hyperaccumulator, produces little biomass (2-5 t/ha) (McGrath et al. Adv. Agronom. 2002) Alyssum bertolonii and Berkheya coddii, Ni hyperaccumulators, produce up to 9-22 t/ha biomass (Robinson, 1997)

Can high biomass compensate for lower accumulation? WHICH PLANT SPECIES FOR PHYTOEXTRACTION? Thlaspi caerulescens can extract 2000 g Cd / ha / year Cannabis sativa Can extract 126 g Cd / ha / year

Hemp as a high biomass plant for phytoextraction? WHICH PLANT SPECIES FOR PHYTOEXTRACTION? Zn toxicity on hemp plants Phytoxicity? Use of fibers after phytoextraction?

Hemp as a high biomass plant for phytoextraction? WHICH PLANT SPECIES FOR PHYTOEXTRACTION? High biomass Not hyperaccumulator Could be used for phytoremediation if fibers can be commercialized

COPPER SOIL CONTAMINATION Copper is required for the physiology of the plant An EXCESS of copper in the soil results in phytotoxic effects Copper is an essential cofactor for many enzymatic activities in animals too An EXCESS of copper is excreted by animals (liver, bile) Genetic diseases result in altered Cu homeostasis (Wilson disease) Exposure to the metal copper may increase the risk of Alzheimer's disease

COPPER SOIL CONTAMINATION Copper sulfate is used in agricuture, including organic farming Possible copper build-up in the soil which at high levels can be harmful to earth worm populations. In response to such environmental concerns copper should be phased out of usage as soon as possible

The aim of this work is the localization of Cu in hemp plants grown in a copper-enriched solution CuSO 4

Energy Dispersive X-ray Spectra (X-EDS) Cu LEAF EPIDERMIS STEM Cu

40  m LEAF EPIDERMIS HYSTOLOGICAL LOCALIZATION OF Cu

80  m TRICOMES HYSTOLOGICAL LOCALIZATION OF Cu

CELL WALL VACUOLE PLASTID CITOLOGICAL LOCALIZATION OF Cu

Hemp grown in hydoponics accumulates cooper in the leaves (tricomes) Copper was not detected in fibers Further work is needed to evaluate the fibers quality from hemp grown in open field in the presence of copper sulfate CONCLUSIONS