Download Eucalyptus-globulus - Cnr-Ibaf

Eucalyptus globulus Labill.
/
Origin and diffusion
Origin: Australia
Distribution: Oceania, Africa, Europe, southern
Photo: V. Buono
/
Photo: V. Buono
America
Invasive potential: low
Photo:V.Buono
Photo: L. Passatore
Photo: L. Passatore
Introduction
Large evergreen tree, with a straight trunk and bent branches, even low positioned, bearing dense
clumps of leaves. Blue gum is characterized by the grey-bluish colour of leaves and the bark; the
latter with the age progressively peels in long strips and emerges smooth bluish-white and pink
areas. The leaves contain terpenes and flavonoids which give it a pungent and very refreshing smell.
The oil extracted from the leaves and the steam has flavouring, antimicrobial and pesticide
properties. The flowers produce copious nectar that yields a strongly flavoured honey. The solid and
flexible structure of the tree makes it an excellent windbreak.
It has a great evapotranspiration potential, enabling it to pump large volumes of water from the soil;
for this reason it has been largely employed for draining wetlands. Eucalyptus forests are particularly
prone to fire-risks but also able to quickly regenerate.
Blue gum, native to Australia, has easily naturalized in other continents due to its rapid growth and
adaptability to a wide range of conditions. It is especially well-suited to countries with a
mediterranean-type climate, but it grows well also in tropics at high altitudes.
Common names: Blue Gum (English), Eucalipto (Italian)
Photo: L.Passatore
Description
Life-form and periodicity: : evergreen tree
Height: 40 – 65 m
Fam. myrtaceae
Description
Roots habit: root system develops mainly in the topsoil but roots can spread several meters deep in
the soil, up to 9 m, in search for water.
Culm/Stem/Trunk: it has a straight trunk up to two-thirds of its total height. The diameter is 1,22,1m.
Bark: it sheds often, peeling in large strips, emerging smooth bluish-white and pink areas.
Leaf: glossy, thick and leathery. The leaves of the young shoots are ovate, opposite, and horizontal,
7-16 cm long, covered with a blue-grey, waxy bloom, which is the origin of the common name "blue
gum"; instead the mature leaves are alternate, 10-30 cm long, sickle-shaped and dark shining
green.
Rate of transpiration: 800-3200 l/day/tree
Reproductive structure: The white flowers are solitary in the leaf axils. The sepals and petals are
united to form a lid which is present on the bud and drops off at anthesis. They are approximately 4 5,5 cm wide and produce copious nectar. The flower has many stamens.
Propagative structure: The fruits are woody capsule and range from 1,5 to 2,5 cm in diameter.
Numerous small seeds are shed through valves (numbering between 3 and 6 per fruit) which open
on the top of the fruit.
Development
Sexual propagation: Eucalypt flowers are mainly pollinated by insects. Most seed is distributed by
wind and gravity, but some is moved by such agents as flood, erosion and birds. Usually seeds fall
out within 300 m from the parent tree. The first seeds to leave the globular capsule are infertile.
The fertile seeds are located at the bottom of the capsule. In the field, germination should occur no
later than 26 days once the appropriate environmental conditions are met. However, seed may
remain dormant for several years under dry conditions..
Asexual propagation: by cuttings
Growth rate: medium
Habitat characteristics
Light and water requirement: It prefers full sun and moist soils.
Soil requirements: it requires moist, clayish and fertile soils. pH from 6.3 to 6.8. It is well-suited to
hydroponic cultivation
Tolerance/sensitivity: it is sensitive to the presence of nitrogen; lack of this element implies a
reduction of the development of the plant. It can grow under a wide variety of agro-ecological
conditions, however it is very sensitive to poor soil structure and shortage or excess of water during
early stages of growth
Phytotechnologies applications
Eucalyptus is an interesting plant for phytoremediation purposes due to its high transpirative activity.
It has been employed mainly in hydraulic containment of landfill leachate and contaminated area
drainage. Furthermore the rapid growth and the potential use of the wood for energy and paper
production, make this species a good candidate for secondary wastewater treatment through tree
irrigation.
Eucalyptus hydroponic cultivation is another good alternative for contaminated water treatment;
several researches demonstrated that eucalyptus is tolerant to heavy metals (Cd, Zn, Cu and Pb)
and to arsenic which accordingly with the low translocation factors measured, tend to accumulate
mainly in roots. The latter are easy to remove in case of hydroponic culture.(King et al., 2008;
Arrigada et al.,2010; Peng et al., 2012;Gomes et al., 2012; Fine et al., 2013)
Furthermore the blue-gum leaves can be used as soil amendment in order to stimulate bacterial
PCB degradation (Hernandez et al.,1997). Lives contain terpenes, structural analogs of PCBs;
these substances act as cometabolite, enhancing the production of enzymes capable to degrade
also PCBs (Passatore et al., 2014).
Phytotechnologies applications
Experimental studies
-Experiment 1-
Reference
Contaminants of concern
Plant species
D. J. King, A. I. Doronila, C. Feenstra, A. J.M.
Baker, I. E. Woodrow, 2008. Phytostabilisation of
arsenical gold mine tailings using four eucalyptus
species: growth, arsenic uptake and availability
after five years. Science of the total environment
406; 35 – 42.
As
E. cladocalyx, E. melliodora, E. polybractea, E. viridis
Mechanism involved in
phytoremediation:
Phytostabilisation/rhizodegradation/phyt
oaccumulation/phytodegradation/phytov
olatilization/ hydraulic control/ tolerant
Types of microorganisms
associated with the plant
Requirements for
phytoremediation
(specific nutrients, addition of oxygen)
Substrate characteristics
Laboratory/field experiment
Age of plant at 1st exposure
(seed, post-germination, mature)
Length of experiment
Initial contaminant concentration
of the substrate
Phytostabilisation
Not reported in the publication
The tailings were covered with various
amendments prior to planting as a previous work
had shown that plants did not grow on raw tailings.
The inclusion of the oxide rock in either milled or
non-milled form has previously been shown to be
important in plant establishment.
The trees were grown on As-rich sulphidic gold
mine tailings, located in Australia.
Sulphur (2–6%) was predominantly present as
pyrite with lesser amounts of arsenopyrite,
pyrrhotite, sphalerite and chalcocite ; arsenic (0.2–
0.4%) was present as pyrite and arsenopyrite).
The high levels of sulphides have not caused acid
generation due to the high neutralizing capacity of
the source material (gypsum salts)..
Field experiment
Young trees
5 years
The total arsenic levels in the experimental plots
were measured at between 0,2 and 0,4% (w/w)
Phytotechnologies applications
Post-experiment contaminant
concentration of the substrate
Post-experiment plant condition
Contaminant storage sites in the
plant and contaminant
concentrations in tissues
(root, shoot, leaves, no storage)
Not reported
It is known that the mine tailings tested here do
retard the growth of eucalypts (Doronila, 2006), the
fact that the plants have survived and are growing,
in some cases quite well, does indicate that the
trees are tolerant to the As concentrations to which
they are exposed.
There was significant variation in height within the
four species. For example, the smallest E.
cladocalyx was just 1,03 m tall after 5 years.
The variation in tree heights was not correlated with
As concentrations in either stems or leaves.
Arsenic was found in all plants grown on the
tailings. The highest concentrations were found in
the leaves, while smaller amounts were found in
the stems.
All four species accumulated low As
concentrations, the highest being recorded in
mature leaves, ranging from 0,29 to 5,14 μg/g As.
E. polybractea had significantly higher foliar As
than the other three species.
Comparison of those samples taken from cores
drilled under trees (<2 m from the nearest tree) with
those taken from cores drilled away from trees (>5
m), showed no significant effect of trees on As
concentrations.
Experiment 2Reference
Contaminants of concern
Plant species
C. Arriagada, G. Pereira , I. Garcıa-Romera, J.A.
Ocampo, 2010. Improved zinc tolerance in
Eucalyptus globulus inoculated with Glomus
deserticola and Trametes versicolor or Coriolopsis
rigida. Soil Biology & Biochemistry 42; 118-124
Zn
Eucalyptus globulus
Mechanism involved in
phytoremediation:
Phytostabilisation/rhizodegradation/phyt Phytostabilisation and phytoaccumulation
oaccumulation/phytodegradation/phytov
olatilization/ hydraulic control/ tolerant
Phytotechnologies application
Types of microorganisms
associated with the plant
Requirements for
phytoremediation
(specific nutrients, addition of oxygen)
Substrate characteristics
Laboratory/field experiment
Age of plant at 1st exposure
Saprophytic fungi: Trametes versicolor and
Coriolopsis rigida.
Arbuscular mycorrhizal: Glomus deserticola
G. deserticola inoculum (root-and-soil inoculum
consisting of rhizosphere soil containing spores
and colonized root fragments of Medicago sativa).
C. rigida or T. versicolor inoculum: sterilized
barleys seeds were used as saprophytic fungal
inoculums carriers. The seeds were inoculated with
a thin slice of potato dextrose agar with mycelia of
the saprophytic fungi
Mixture of sterilized sand:soil at a proportion of 1:1
(V:V). The soil, classified as an Andisol (Acrudoxic
Hapludands), with low P content (7,3 mg/kg,
NaHCO3-extractable), is moderately acidic (pH
5,4) with good drainage and water infiltration.
Laboratory experiment (in vitro and greenhouse).
Seedlings
(seed, post-germination, mature)
Length of experiment
Initial contaminant concentration
of the substrate
Post-experiment contaminant
concentration of the substrate
Post-experiment plant condition
Contaminant storage sites inthe
plant and contaminant
concentrations in tissues
(root, shoot, leaves, no storage)
133 days
In vitro experiment: in Petri dishes Zn
concentrations were 0, 10, 20, 50, 100, and 200
mg Zn/l.
Greenhouse experiment. Plants grown at different
Zn concentrations (): 0, 10, 100, 500 and 1000
mgZn/Kg soil
In vitro experiment: the concentration of Zn in the AG
growth medium decreased 51-67% after culture with C.
rigida and 54-66% after culture with T. versicolor.
Greenhouse experiment: in the presence of 500 and 1000
mg kg/l Zn, there were higher metal concentrations in roots
and shoots of arbuscular mycorrhizal than in non-arbuscular
mycorrhizal plants; furthermore, both saprophytic fungi
increased Zn uptake by trees colonized by G. deserticola.
At doses higher than 100 mg Zn per kg or liter, the shoot
dry weight of plants decreased in all treatments. Plants
colonized with Glomus deserticola were less affected than
plants not colonized with arbuscular mycorrhizal.
The saprophytic fungi T. versicolor and C. rigida increased
the shoot dry weight and the tolerance of E. globulus to Zn
when these plants were mycorrhizal-colonized.
Both saprophytic fungi increased the percentage of
arbuscular mycorrhizal root length colonization and
elevated its metabolic activity.
The higher root to shoot metal ratio observed in
mycorrhizal plants indicates that G. deserticola
enhanced Zn uptake and accumulation in the root
system, playing a filtering/sequestering role in the
presence of Zn.
Phytotechnologies applications
-Experiment 3-
Reference
Contaminants of concern
C. Arriagada, E. Aranda, I. Sampedro, I. GarcıaRomera, J.A. Ocampo, 2009. Interactions of
Trametes versicolor, Coriolopsis rigida and the
arbuscular mycorrhizal fungus Glomus deserticola
on the copper tolerance of Eucalyptus globulus.
Chemosphere 77: 273–278
Cu
Mechanism involved in
phytoremediation:
Phytostabilisation/rhizodegradation/phyt Phytostabilisation and phytoaccumulation
oaccumulation/phytodegradation/phytov
olatilization/ hydraulic control/ tolerant
Types of microorganisms
associated with the plant
Requirements for
phytoremediation
(specific nutrients, addition of oxygen)
Substrate characteristics
Laboratory/field experiment
Age of plant at 1st exposure
(seed, post-germination, mature)
Length of experiment
Initial contaminant concentration
of the substrate
Post-experiment contaminant
concentration of the substrate
Saprophytic fungi: Trametes versicolor and Coriolopsis
rigida.
Arbuscular mycorrhizal: Glomus deserticola
G. deserticola inoculum (root-and-soil inoculum
consisting of rhizosphere soil containing spores and
colonized root fragments of Medicago sativa).
C. rigida or T. versicolor inoculum: sterilized barleys
seeds were used as saprophytic fungal inoculums
carriers. The seeds were inoculated with a thin slice of
potato dextrose agar with mycelia of the saprophytic
fungi.
Mixture of sterilized sand:soil at a proportion of 1:1
(V:V). The soil, classified as an Andisol (Acrudoxic
Hapludands), with low P content (7,3 mg/kg, NaHCO3extractable), is moderately acidic (pH 5,4) with good
drainage and water infiltration.
Laboratory experiment (in vitro and greenhouse)
Seedlings
12 weeks
In vitro experiment: in Petri dishes concentrations were 0,
10, 20, 30, 60, and 100 mg Cu/l.
Greenhouse experiment plants were grown at different
Cu concentrations: 0, 10, 100, 1000 and 2000 mgCu/Kg
soil.
In vitro experiment: the Cu concentration in the AG
growth medium decreased between 53% and 66%
after culture of C. rigida and between 26% and 47%
after culture of T. versicolor.
Phytotechnologies applications
Post-experiment plant condition
Contaminant storage sites in the
plant and contaminant
concentrations in tissues
(root, shoot, leaves, no storage)
The presence of high levels of Cu in soil decreases the
shoot and root dry weights of E. globulus.
However, higher plant tolerance of Cu has been
observed in the presence of the fungus G. deserticola.
In contrast with other essential metals, Cu is toxic to
most fungi even at very low concentrations (Baldrian,
2003). Only the C. rigida- G. deserticola combination
increased the tolerance of plants to Cu.
It is known that E. globulus was able to accumulate
heavy metals in the stem more than in the leaves.
The absence of a higher root to shoot metal ratio in
the mycorrhizal plants (1,70 – 0,11) indicated that
G. deserticola did not play a filtering/sequestering
role against Cu.
Plants colonised by G. deserticola had higher
metal concentrations in the roots and shoots than
do non-mycorrhizal plants.
Best results have been achieved with the
inoculation of G. deserticola + C. rigida, it increased
the plant Cu uptake to levels reached by
hyperaccumulative plants (up to 400 mg/Kg in
shoots and 800 mg/Kg in roots).
Plants inoculated only with C. rigida and T.
versicolor did not accumulate more Cu than noninoculated controls.
-Experiment 4Reference
Contaminants of concern
C. Arriagada, M. A. Herrera, F. Borie, J.A.
Ocampo, 2007. Contribution of Arbuscular
Mycorrhizal and Saprobe Fungi to the Aluminium
Resistance of Eucalyptus globulus. Water Air Soil
Pollut 182:383–394
Al
Mechanism involved in
phytoremediation:
Phytostabilisation/rhizodegradation/phyt Phytostabilisation and phytoaccumulation
oaccumulation/phytodegradation/phytov
olatilization/ hydraulic control/ tolerant
Types of microorganisms
associated with the plant
Saprophytic fungi: Fusarium concolor and Trichoderma
koningii
Arbuscular mycorrhizal: Glomus mosseae and
Glomus deserticola
Phytotechnologies applications
Requirements for
phytoremediation
(specific nutrients, addition of oxygen)
Substrate characteristics
Laboratory/field experiment
Age of plant at 1st exposure
(seed, post-germination, mature)
Length of experiment
Initial contaminant concentration
of the substrate
Post-experiment contaminant
concentration of the substrate
Post-experiment plant condition
The possibility of manipulating an arbuscular
mycorrhizal inoculation together with a saprobe
fungus conferring high aluminium tolerance and
accumulation in the shoot by E. globulus could be a
good alternative for stimulating plant growth under
adverse conditions, such as in soils where acidic
conditions and low levels of P, Ca and Mg may
contribute to aluminium toxicity.
In vitro experiment: The AG medium consisted of 1
g glucose, 0,4 g asparagine, 0,05 g MgSO4, 0,05
KH2PO4 and 100 ml distilled water.
Greenhouse experiment: mixture of sterilized
sand:vermiculite:sepiolite at a volume proportion of
1:1:1.
Laboratory experiment (in vitro and greenhouse)
Seedlings
16 weeks
In vitro experiment: concentrations in Petri dishes
were 0, 500 and 1000 mg Al/l.
Greenhouse experiment plants were grown at
different Cu concentrations: 0, 150, 600, 1500 and
3000 mgAl/Kg substrate.
Not reported in the publication
The application of 1500 mg/kg decreased the shoot
and root dry weight, chlorophyll content and total P,
Mg, and Ca concentrations in the shoot of E. globulus.
Neither saprobe fungi gave any additional aluminum
tolerance to E. globulus. However, both mycorrhizal
fungi G. mosseae and G. deserticola inoculated alone
increased the shoot dry weight of Eucalyptus, with the
latter being significantly higher, even at the application
rate of 1,500 mg kg−1
The application of 3,000 mg kg−1 decreased the shoot
dry weight of plants in all treatments tested.
the shoot:root ratio increased with both strains of
mycorrhizal inoculum, with G. deserticola being higher;
this suggests a greater beneficial effect on plant growth
produced by such a mycorrhizal strain.
Phytotechnologies application
Contaminant storage sites in the
plant and contaminant
concentrations in tissues
(root, shoot, leaves, no storage)
Aluminum concentration in shoots of E. globulus
plants did not show any differences either at lowest
(150 mg kg−1) or highest (3,000 mg kg −1)
concentrations when plants were not affected either
by AMF or saprobe fungi inoculation.
However, at 600 and 1500 mg kg−1, both Glomus
strains produced a significant increase in shoot
aluminum concentration, which was not reinforced
by the two inoculated saprobe fungi.
In addition, at the same aluminum level in the
growth media, the effect of T. koningii was
synergistic with what was presented by G.
deserticola inoculation and the highest aluminum
concentration was obtained (approximately 27 mg
kg−1). Aluminum shoot content in this last
treatment increased approximately sixfold in
comparison to those obtained in control plants.