Pteris vittata L.
Origin and diffusion
Origin: tropical areas Distribution: sub-cosmopolitan Invasive potential: medium
Source: www.plants.usda.gov
Photo: G. Nicolella Photos: L. Passatore
Introduction
P. vittata is a perennial fern, native to tropical regions and naturalized throughout much of the world It has pinnate fronds tufted or closely spaced, herbaceous to slightly coriaceous. It is a pioneer species, typically growing in humid environments like most of the ferns, it colonizes walls, cliffs and rocks,
usually in shade. This species has been one of the most investigated plant for phytotechnologies purposes, as it has been found to be able to take up prodigious amounts of arsenic from soil and sequester it mostly in the above-ground biomass.
Common names: Chinese brake (English), Pteride a foglie lunghe (Italian)
Description
Life-form and periodicity: perennial, evergreen
Height: 0,3-0,5 m
Roots habit: strong creeping rhizome, with very abundant and thin rhizoids (which serve no other function than attachment). Maximum root-system depth: 30 cm. Culm/Stem/Trunk: - Crown: -
Fam. Poaceae
Description
Leaf: tufted fronds, arching, leathery, pinnate, with an elliptic shape.
Rate of transpiration: -
Reproductive structure: fertile fronds bear sporangia (spore producing structures) on the underside of fronds. A group of sporangia is referred to as a sorus. Sori are disposed in a sub-marginal line along both sides of the pinna, from near the base to near the tip. Propagative structure: spores
Development
Sexual propagation: The drying of the sporangia catapults the mature spores from the fern in order to disperse spores outside the immediate neighborhood of the parent, thus aiding in wide-range dispersal. Spores of brake fern because of their small size compared to most ferns, are capable of reaching high altitudes through atmospheric winds and attain extreme long distance dispersal.
Asexual propagation: it takes place by progressive death and decay of older portions of the rhizome. When the decay reaches the point of branching, the main axis and branch are separated and grow as individual plants.
Growth rate: fast
Habitat characteristics
Light and water requirement: it prefers moist soils and shadow but tolerates dry conditions and bright sunlight.
Soil requirements: it can grow on almost any calcareous substrate, alkaline pH, such as sites contaminated with arsenic.
Tolerance/sensitivity: it is well adapted to poor soil, but it can’t grow in lack of water or in clayey substrates. It can afford moderate soil salinity.
Phytotechnologies applications
Pteris vittata naturally inhabited sites contaminated with arsenic, it has been reported that this species can take up prodigious amounts of this chemical element from soil and sequester it mostly in the above-ground biomass, reaching in his tissues over 40 times the concentration of the substrate (Ma et al., 2001). In addition to being an arsenic hyperaccumulator, this species is very suitable to be used for phytoremediation purposes tanks to its rapid growth, to its ease of propagation and to its evergreen and perennial life-form. This species can act not only on soil or sediment but also on As polluted waters, being easily cultivable in hydroponics.
Wang et al. (2002) reported that increasing phosphate supply in the substrate, the As uptake in the fern tissues decreased markedly, it is therefore advisable to limit the presence of phosphate in phytoremediation applications with this plant.
Experimental studies
S. Tu, L. Q. Ma, A. O. Fayiga, E. J. Zillioux, 2004. Reference Phytoremediation of Arsenic-Contaminated groundwater by the Arsenic Hyperaccumulating Fern Pteris vittata L.. International Journal of Phytoremediation, 6(1):35–47.
Contaminants of concern Arsenic
Mechanism involved in phytoremediation: Phytostabilisation/rhizodegradation/phyt Phytoaccumulation oaccumulation/phytodegradation/phytov olatilization/ hydraulic control/ tolerant
Laboratory/field experiment Laboratory experiment (hydroponics)
Types of microorganisms Not reported in the publication associated with the plant A plastic tank filled with granular gravel may be Requirements for feasible to remove arsenic from groundwater in a phytoremediation large-scale operation. Phosphorus should be (specific nutrients, addition of oxygen) excluded or reduced since it competes with plant arsenic uptake.
Length of experiment 3 days
Age of plant at 1st exposure 3-month old fern plants (seed, post-germination, mature) Initial contaminant concentration Polluted groundwater had concentrations of total As of 46 μg/l and As (III) of 1.6 μg /l. of the substrate
Phytotechnologies applications
Experiment n. 1 (effects of P addiction, plant density, plant re-use and plant age)
Control: arsenic-contaminated groundwater. Experimental solution: the same groundwater amended with P-free or P-rich 20% Hoagland– Arnon nutrition solution. Substrate characteristics Solution pH for all treatments was adjusted to 7.0 normalized to the groundwater’s pH. Experiment n. 2 (setup of groundwater remediation) Plastic tank filled with granular gravel (crushed stone, about 0.5–1 cm in size) and 8 L of arsenic- contaminated groundwater . Experiment n. 1 (effects of P addiction, plant density,
plant re-use and plant age) Within 3 days the arsenic concentrations in the groundwater decreased from 28 to 5 μg/l for a single plant. This indicates that one plant was sufficient to remove arsenic from 600 ml groundwater in 3 days. The arsenic-depletion rate by a 12-month-old fern plant was just 42–52% of that observed for 3-month-old fern plants at the end of 3 days Post-experiment contaminant The calculated uptake rates at 72 h were (nmol/g of root f.wt h): concentration of the substrate 0.41 ± 0.064 for the control, 0.44 ± 0.065 for solution P free and 0.092± 0.027 for solution P-rich The results indicated that supplying P to the groundwater significantly inhibited arsenic-uptake rates. Experiment n. 2 (setup of groundwater remediation)
56% of arsenic in 8 L of groundwater was removed by 20 plants in 1 day, reaching 20 μg/l. After 3 days, the arsenic concentration in the groundwater was below 10 μg/l
Post-experiment plant condition Not reported in the publication.
Contaminant storage sites in the plant and contaminant Not reported in the publication. concentrations in tissues (root, shoot, leaves, no storage)
Phytotechnologies applications
Reference Sugawara, K., Kobayashi, A., Endo, G., Hatayama, M., & Inoue, C. (2014). Evaluation of the effectiveness and salt stress of Pteris vittata in the remediation of arsenic contamination caused by tsunami sediments. Journal of Environmental Science and Health, Part A, 49(14), 1631-1638. Contaminants of concern Arsenic and salt (NaCl) Mechanism involved in phytoremediation: Phytostabilisation/rhizodegradation/phyt Phytoaccumulation oaccumulation/phytodegradation/phytov olatilization/ hydraulic control/ tolerant Laboratory/field experiment Laboratory experiment (germination on agar plates and plant survival in pots) Types of microorganisms Not reported in the publication associated with the plant Requirements for Soil with high sulfate concentration, , was found to be phytoremediation not suitable for phytoremediation by P. vittata. (specific nutrients, addition of oxygen) Soil characteristics Saline polluted sediments affected by tsunami event mixed with peat moss and sand Soil 1: pH=7,35, Soil 2: pH=7.3, Length of experiment 35 days (incubation time of pot experiment for salt stress assay), 166 days (incubation time of pot experiment for phytoaccumulation assay) Age of plant at 1st exposure Spore (in agar plates) and 3-month-old ferns (in (seed, post-germination, mature) pots). Soil 1: Total As (mg/kg)=22.4, Initial contaminant concentration Soluble As (μg/L)=3.39 of the substrate Soil 2: Total As (mg/kg)=9.4, Soluble As (μg/L)=1.52 The soluble As of the soil without planting got increased after 5 months since tsunami sediments were brought up from anaerobic to aerobic Post-experiment contaminant condition; In soil sample 2, where growth inhibition concentration of the substrate was observed, there was no change in soluble As in the soil. However, the soluble As in soil sample 3 had declined. Conclusion: the fern decreased water soluble As of soil by half.
Phytotechnologies applications
Salt stress test: the addition of NaCl delayed spore germination, the germination rate with 50 mM NaCl declined slightly to 90% and to 20% with 100mM NaCl; growth inhibition was observed with the ferns immersed in 400 and 600 mM solutions. More than 66.2 mS/m EC was detrimental to the growth of the fern, which related with 30 days of growth. In the sampled soil, 79.5 mS/m EC was Post-experiment plant condition detrimental to the fern's survival, after at least 35 days. Thus, phytoremediation of the fern should be applied to soil when the EC is lower than 66.2 mS/m. Phytoaccumulation test: the fronds grown in As polluted soil were fewer and were light-colored and yellowish, the plant growth was slower and the biomass was smaller.
Contaminant storage sites in the plant and contaminant P. vittata accumulated 264 mg/kg DW As in the concentrations in tissues shoot (root, shoot, leaves, no storage)