Salix Viminalis
Salix viminalis
INTRODUCTION Root habit It has an extensive root system that makes it It is a multistemmed shrub; it has long, erect, able to grow on really bad soils. straight branches with greenish-grey bark. The root system is rather aggressive and can It grows in wet places beside rivers and pools, cause problems with drains. Plants are best not or more frequently in Osier-beds. grown within 10 metres of buildings. The exact native range is uncertain due to extensive historical cultivation.
Photo: www.upload.wikimedia.org . By Hugo.arg Photo: www.bluestem.ca
GENERAL INFORMATION Foliage
Scientific name: S. viminalis Leaf arrangement: alternate, simple, Family: Salicacae Leaf shape: long and slender Common name(s): Common Osier : dark green above, with a silky (English), Salice da vimini (Italian) Leaf color grey-haired underside Habitat description: wetland and flooded;
(0-500 m, rarely 1500 m); World range: cold zones of Eurasia
DESCRIPTION
Height: 3-6 m Crown shape: rather narrow, truncate or rounded Growth rate: fast-growing Bark: greenish-grey, fissured
Photo: www.plant-identification.co.uk
Flower
The flowers are catkins, produced in early spring before the leaves and pollinated by insects. Flower colour: yellow Flower characteristics: dioecious, with
Photo: www.fungoceva.it male and female catkins on separate trees. The male catkins are yellow and oval-shaped; USE AND MANAGEMENT the female catkins are longer and more cylindrical; Along with other related willows, the flexible twigs (called "withies") are commonly used in Fruit, Seed basketry, giving rise to its alternative common The fruits are capsules that split open in early name of "basket willow summer to release the numerous minute seeds. Another increasing use is in energy forestry, effluent treatment, wastewater gardens and CULTURE water purification..
Light requirement: full sun to part shade PESTS AND DISEASES Soil tolerance: thrives with regular deep watering; tolerates a wide variety of soil types Plants in this genus are notably susceptible to but prefers a damp, heavy soil. Rarely thrives honey fungus. on chalk Atmospheric pollution tolerance: good Wind tolerance: high
USE IN PHYTOREMEDIATION
------Experiment 1------
Contaminants of concern Cr, Co, Ni, Cu, Zn, Cd, Pb.
Plant species Salix viminalis
Interaction of plant and contaminants: Phytoremediation Tolerant plant (enhancement of microbial community) / phytoremediation
Mechanism involved: Phytoaccumulation Phytostabilisation/rhizodegradation/phytoaccumul ation/phytodegradation/phytovolatilization/ evapotraspiration
Types of microorganisms associated with Not reported in the pubblication. the plant
Laboratory/field experiment Laboratory experiment (hydroponics in greenhouse)
Initial contaminant concentration Concentrations in the hydroponic solution: 0.1, 0.5, 1 and 1.5 mmol of seven heavy metals: Cd, Co, Cr, Cu, Ni, Pb, and Zn.
Length of Experiment 64 days
Post-experiment contaminant content The table below (from the reported publication) shows the encrease (%) of the heavy metal content in the roots of experimental groups after ncubation in solutions of different ion concentration [mg/Kg]
Post-experiment plant condition It can be predicted that 2- and 3-year-old plants are most effective for remediation purposes. They exhibit the highest resistance to stress and better adaptation ability than 1- year-old plants.
Solution characteristics Standard Knop medium, with pH of 4.24 and 4.01 at the beginning and end of the experiment, respectively.
Age of plant at 1st exposure Cuttings (after a preliminary incubation lasted (seed, post-germination, mature) for 14 days without contaminants)
3 −3 Requirements for phytoremediation 5 cm EDTA solutions (0.05 mol dm ) were (specific nutrients, addition of oxygen) added to each container, in order to enhance bioavailability and facilitate transport of the metals to the plant tissues
Contaminant storage sites in the plant Not reported in the pubblication. (root, shoot, leaves, no storage)
Reference M. Mleczeka, M. Łukaszewski, Z. Kaczmarekb, I. Rissmanna, P. Golinski, 2009. Efficiency of selected heavy metals accumulation by Salix viminalis roots. Env. and Exp. Botany 65; 48–53
------Experiment 2------Contaminants of concern Zn, Cd
Plant species Salix viminalis
Interaction of plant and contaminants: Significant relation was found between soil Tolerant plant (enhancement of microbial total Zn or Cd and foliar Zn or Cd; it makes community) / phytoremediation willows useful bioindicators.
Mechanism involved: Phytoaccumulation Phytostabilisation/rhizodegradation/phytoaccumul ation/phytodegradation/phytovolatilization/ evapotraspiration
Types of microorganisms associated with Not reported in the publication the plant
Laboratory/field experiment Field experiment
Initial contaminant concentration Soil Cd and Zn concentrations varied between 6,8 and 13,9 mg/kg DW for Cd, and between 841 and 1456 mg/Kg DW for Zn, according to the landfill sites where willow was sampled
Length of Experiment 4 years (To determine temporal variability of the foliar concentrations, samples were taken yearly during 4 years)
Post-experiment contaminant content The graphic below (from the reported publication) shows the foliar Cd (a) and Zn (b) concentrations expressed on a dry weight base relative to soil concentrations for willows sampled (S.Alba, S.Cinerea, S.viminalis and S.caprea) on 12 dredged sediment landfills. The graphic has been extrapolated from the reported publication.
Post-experiment plant condition Not reported in the publication
Soil characteristics Polluted dredged sediment landfills characterised by high clay and organic matter content. The table below (from the reported publication) shows soil properties (minimum and maximum) of the landfills where volunteer willow vegetation was established.
Age of plant at 1st exposure Not reported in the publication. (seed, post-germination, mature)
Requirements for phytoremediation Not reported in the publication (specific nutrients, addition of oxygen)
Contaminant storage sites in the plant Not reported in the publication (root, shoot, leaves, no storage)
Reference B. Vandecasteelea, B. De Vosa, F. M.G. Tack, 2002. Cadmium and Zinc uptake by volunteer willow species and elder rooting in polluted dredged sediment disposal sites . The Science of the Total Environment 299; 191– 205
------Experiment 3------
Contaminants of concern Mineral oil, PHAs, Cd, Cu, Pb, Zn.
Plant species Salix viminalis (clone Orm)
Interaction of plant and contaminants: Phytoremediation Tolerant plant (enhancement of microbial community) / phytoremediation
Mechanism involved: Phytostabilisation and evapotranspiration, Phytostabilisation/rhizodegradation/phytoaccumul phytoaccumulation of heavy metals ation/phytodegradation/phytovolatilization/ (moderate), rhizodegradation (microbial evapotraspiration degradation) of mineral oil and PAH. . Types of microorganisms associated with Not reported in the publication. the plant
Laboratory/field experiment Field experiment
Initial contaminant concentration Mean (± S.D.) heavy metal concentrations expressed in mg/Kg : Cd: 3 ± 1.1 Pb: 142.9 ± 59.5 Zn: 437.3 ± 128.4 Cu: 72.5 ± 42.9 The table below (from the reported publication) shows the concentrations (mg/kg) of mineral oil and PAH in sediment before the treatment.
Not reported in the publication. Length of Experiment
After the second growing season, a significant Post-experiment contaminant content decrease of 57% in the mineral oil
concentration of the sediment in the planted
disposal site was observed while mineral oil
degradation in sediment of the fallow site was
only 15%
The total PAH degradation was most
pronounced in the fallow sediment; a
significant reduction of the total PAH content
by 32% after 1.5 years was observed in the
fallow sediment compared with 23% in the
planted sediment.
Post-experiment plant condition Not reported in the publication
Soil characteristics The physical and chemical characteristics of
the sediment in both disposal sites are
presented in the table below (from the
reported publication).
Willows was planted through vegetative Age of plant at 1st exposure reproduction from horizontally inlaid willow (seed, post-germination, mature) rods.
No requirements. Requirements for phytoremediation
The table below (from the reported Contaminant storage sites in the plant publication) shows the mean metal (root, shoot, leaves, no storage) concentrations (mg/kg) and bioconcentration factors (BCF) in the biomass compartments of willows.
Cd was the only metal with a bio
concentration Factor (BCF) >1 in all
compartments, showing a pronounced
bioaccumulation.
The higher concentrations found in the litter
may indicate an export of metals to the leaves
prior to leave senescence.
P. Vervaeke, S. Luyssaert, J. Mertens, E. Reference Meers, F.M.G. Tack, N. Lust, 2003. Phytoremediation prospects of willow stands on contaminated sediment: a field trial. Environmental Pollution 126; 275–282
------Experiment 4------
Contaminants of concern Cd
Plant species Salix viminalis (clone 78183)
Interaction of plant and contaminants: Phytoremediation Tolerant plant (enhancement of microbial community) / phytoremediation
Mechanism involved: Phytoaccumulation Phytostabilisation/rhizodegradation/phytoaccumul ation/phytodegradation/phytovolatilization/ evapotraspiration
Types of microorganisms associated with Not reported in the publication. the plant
Laboratory/field experiment Field experiment.
Initial contaminant concentration Concentrations of Cd extractable with 7 M HNO3 and NH4NO3 in different soil horizons:
Cd-HNO3 (mg/kg DW) In plough layer: 0.17-0.45 In upper subsoil: 0.11-0.31 In lower subsoil: 0.08-0.24
Cd-NH4NO3 (μg/kg DW) In plough layer: <0.1-34 In upper subsoil: 0.2-45 In lower subsoil: <0.1-64
Length of Experiment Tree years (sampling time).
Post-experiment contaminant content The average Cd concentration in the plant during the study period ranged between 0.6 and 4.1 mg/kg in the stems and between 1.0 and 7.3 mg/kg in the leaves.
Post-experiment plant condition Stem biomass production varied between 2.1 and 8.7 tonnes/ha year. Stands with high biomass production tended to have lower stem and leaf Cd concentrations than stands with low biomass production High yielding stands were also usually found on non-acid soils, whereas less productive stands usually grew on more acid soils.
Soil characteristics Investigation was conducted on three different soil types with respect to pH. pH ranged between 6.4 and 7.7 in the plough, 6.2 and 8.0 in the upper layer, 5.6 and 8.4 in the lower layer. CaCO3 content (% of DW) varied between 0.2 and 3.8. Organic C content (% of DW): 0.3 – 4.1 Clay content in the plough layer varied between 40 and 60% and the soil texture class was clay.
Age of plant at 1st exposure Cuttings. During the first year of the (seed, post-germination, mature) investigation the stands were in their 1st or 2nd cutting cycle and shoot age varied between 1 and 4 years
Requirements for phytoremediation The stands had all been fertilised with either (specific nutrients, addition of oxygen) commercial N-fertilisers alone or with commercial N-fertilisers in combination with sewage sludge.
Contaminant storage sites in the plant The leaves had significantly higher Cd (root, shoot, leaves, no storage) concentrations than the stems in all the stands investigated.
Reference E. K. Westin, J. Eriksson, 2003. Potential of Salix as phytoextractor for Cd on moderately contaminated soil. Plant and Soil 249: 127– 137