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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
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