Copper localization in Cannabis sativa grown in a copper-rich

solutionPiera 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

M O B I L I Z A T I O N

H -AT P ase+

H + H + SOILM n+M

M n+

M A LIC A CIDCITR IC A CID

CE L LWAL L

M

RO O T UP TAK E

H + H +

M n +M n+

M

M

M M

M

M

M

M

CE LLWALL

P LA SM AM E M BR AN E

H -ATP ase+VAC UO LE

CITO S O LICCH ELATO RS

XILEMATIC TRANSPORT

M n+

M n +M n +M n +M n +

M

M

M

ce ll.transfer

XILE MPAR ENC HIM AT IC

CE LLS

DIFFUSIO N

floem a

AP O PLAS TICL O ADING

?

SY M PLAS TICLO AD ING

HY STO LO G ICAL L O CAL IZATIO N

M n+

M

M n +

M

M

T RICO M ES

xilemAP O PLAS TICT RANS PO R T

SY M PLAS TICT RANS PO R T

CELL UPTAKE AND COMPARTIMENTATION

M

M

MM M

M

M

M

M

MM

GOLGI

NUCLEUS

PLASMA MEMBRANE

metal-chaperonines

VACUOLE

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 SPECIESRepresent <0,2% of all angiosperms

~400 species are hyperaccumulators

HYPERACCUMULATION THRESHOLDS: Zn, Mn: 10 000 mG/KG

Co, Cu, Ni, Se: 1 000 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 22 000 mG/KG of arsenic, with no phytotoxicity simptoms up to 10 000 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 caerulescenscan extract 2000 g Cd / ha / year

Cannabis sativaCan 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

CuSO4

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

CIT

OLO

GIC

AL

LOC

ALI

ZA

TIO

N O

F C

u

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