Page 180 - AJWEP-22-6

Ehsan, et al.

Table 3. Comparison of different phytoremediation strategies
Plant Zinc Zinc concentration in Medium, time of Tolerance References
Concentration in plant (mg/kg) exposure index (%)
medium (mg/kg)
Lupinus uncinatus 600 10,000 (root); 18,000 Soil in pot, 14 days 149 The present
(shoot) study
Lupinus albus 500 5,200 (root); 1,638 (shoot) Soil in pots, 84 days 38 32
Brassica juncea 6.5 mg/L 10,000 (root); 1,500 (shoot) Hydroponics, 12 days 122 49
Thlaspi caerulescens 210 1,200 (root); 8,700 (shoot) Soil in pots (industrial – 50
contamination), 100 days
Hordeum vulgare 100 1 (root); 4.5 (plant) Soil in pots, 48 days 41 51
(barley, non-tolerant)

of metals within plants, particularly their transport
from roots to aerial tissues. Despite the relative short
exposure period of 2 weeks, considerably elevated Zn
concentrations were detected in the roots, stems, and
leaves of L. uncinatus.
As shown in Figure 2, Zn concentrations in all plant
parts increased proportionally with rising Zn supply
levels, indicating the substantial accumulation potential
of this species under the experimental conditions.
These findings are consistent with previous reports
for L. albus by Ximénez-Embún et al. and Pastor
37
et al. In L. uncinatus, Zn concentrations in stems
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ranged from 3,720 mg Zn/kg to 14,771 mg Zn/kg,
while leaves contained 3,090–4,062 mg Zn/kg. Roots
accumulated between 5,818 and 10,568 mg Zn/kg. For
comparison, Noccaea caerulescens (formerly known as Figure 2. Zinc (Zn) uptake by roots and its
Thlaspi caerulescens) can accumulate up to 40,000 mg accumulation and transport to aerial tissues
Zn/kg in shoot dry biomass without toxic symptoms, 52,53 (stems and leaves) of Lupinus uncinatus exposed to
whereas the normal Zn concentration in most plants is different Zn supply levels for 2 weeks
30–100 mg/kg dry mass. 54 Notes: Vertical bars represent ± SE (n=4). Zn
These results demonstrate that L. uncinatus is capable 000 corresponds to the control (65 mg/kg soil Zn
of substantial Zn uptake under slightly acidic conditions without additional Zn application); Zn 200, Zn 400,
(as tested in the present study). Given that neutral soils and Zn 600 represent Zn supply levels of 200, 400, and
are among the preferred environments of this species, 600 mg/kg, respectively.
55
it is reasonable to infer that similar uptake potential may
also occur under neutral conditions. 10–100 μM As showed enhanced tolerance to arsenate,
They also align with observations by Pastor et al., supporting its potential application in phytoremediation
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who reported Zn uptake of 3,605 mg Zn/kg in L. albus or revegetation of As-contaminated sites.
grown in acidic soil contaminated with 300 mg Zn/kg. Additional studies further confirm the capacity of
Furthermore, lupins have been reported to accumulate lupins to thrive under metal stress. For example, L. albus
other heavy metals. For instance, L. albus accumulated grown in vermiculite with elevated Zn concentrations
4,900, 2,300, 400, and 200 mg/kg of Cd, Hg, Pb, and at pH 6.7 for 3 weeks achieved Zn concentrations of
Cr, respectively, when grown in contaminated sand. In 1,400 mg/kg of Zn in shoots and 4,100 mg/kg in roots.
37
32
related experiments using soil and nutrient solution, Zn and Among Andean high-elevation plants, L. ballianus
Cd accumulation in different plant parts of L. uncinatus exhibited the highest Cd accumulation in roots, with
was also observed. 56,57 Similarly, Vázquez et al. reported 287.3 mg/kg dry matter when grown in a substrate
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that the growth of L. albus grown in perlite containing consisting entirely of mine waste. 41

Volume 22 Issue 6 (2025) 174 doi: 10.36922/AJWEP025140101