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Zn accumulating behavior of L. uncinatus

Martínez-Alcalá et al. reported that Zn concentrations 3.4. Metal distribution within L. uncinatus at
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were slightly higher in shoots (46 ± 10 μg/g) than in various zinc concentrations
roots (34 ± 1 μg/g of L. albus cultivated for 74 days The distribution of Zn in leaves, stems, and roots
in calcareous pot soil containing high levels of Zn and varied across treatments. Zn concentration in the shoots
Pb (2,058 and 2,947 μg/g, respectively). Similar shoot (stems and leaves) increased, while root concentrations
concentrations (40–70 μg/g) were reported in L. albus decreased, with increasing Zn supply levels from 200 to
without apparent detrimental effects. In contrast, 600 mg Zn/kg (Figure 3).
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other studies have demonstrated that Zn absorbed by At 200 mg Zn/kg, 54% of total Zn uptake was
this species can accumulate predominantly in roots, allocated to the shoots (stems + leaves) and 46% to the
particularly when soil amendments are applied to roots. By contrast, at 600 mg Zn/kg, shoot allocation
stabilize metals in the soil. 31,61 Taken together with increased to 64% while root allocation decreased to
the findings of the present study, Lupinus species hold 36%. These results indicate that:
considerable potential for phytoremediation of metal- (i) At higher Zn concentrations, shoots tend to
contaminated soils. accumulate a greater proportion of the absorbed
A notable feature of Zn accumulation in L. uncinatus metal, as previously reported; 36
is the relatively high concentrations detected in stems and (ii) The shift in Zn partitioning with increasing
leaves compared with roots, as reflected by shoot-to-root contamination may represent an adaptive response
ratios approaching 1.78 at the 600 mg/kg treatment mechanism to mitigate the imposed metal stress.
(Table 4). Ratios >1 indicate efficient translocation of The presented data indicate that L. uncinatus
Zn from roots to shoots, with Zn mobility increasing possesses a considerable capacity for Zn accumulation,
with high Zn additions to the soil. reflected in high metal IT values, shoot-to-root ratios
Lupin plants have also demonstrated strong above 1, and increased dry biomass under Zn stress.
root-to-shoot transport capacity in the case of Hg Although root growth showed a significant reduction
hyperaccumulation, suggesting the presence of in dry weight after 2 weeks of exposure, overall plant
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an underlying cellular mechanism for heavy metal biomass exhibited a stimulatory effect relative to the
transport. In addition to efficient uptake, it is possible control.
that lupin roots may also enhance the bioavailability of The mobility of Zn within plants is generally
heavy metals in the rhizosphere, thereby enlarging the considered intermediate, falling between highly mobile
pool of Zn available for uptake. In general, Zn-efficient elements such as potassium and phosphorus and relatively
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genotypes (e.g., oilseed rape) tend to contain lower immobile elements such as calcium. Nevertheless, Zn
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Zn concentrations in roots and higher concentrations has been found to be readily transported in the phloem
in young leaves, indicating a superior capacity for Zn of some species (e.g., wheat). 63-65 Furthermore, Zn
translocation and utilization. 62
The mechanisms governing Zinc uptake and
translocation in lupins, as well as the effect of soil
factors on these processes, remain poorly characterized
due to the limited literature available. Nonetheless,
the observed accumulation and distribution patterns
highlight the potential value of Lupinus species as
phytoremediators in slight acidic or neutral soils.

Table 4. Shoot-to-root Zn concentration ratios
in Lupinus uncinatus grown in Zn-contaminated
soil (n=4)
Zn supply levels (mg/kg) Shoot: Root Zn ratio Figure 3. Zinc (Zn) distribution in different plant
Control 1.06±0.10 parts of Lupinus uncinatus grown at different Zn
supply levels for 2 weeks (n = 4)
200 1.17±0.14 Notes: Zn 00 corresponds to the control (65 mg/kg soil
400 1.63±0.22 Zn without additional Zn application; Zn 200, Zn 400,
600 1.78±0.19 and Zn 600 represent Zn supply levels at 200, 400, and
Abbreviation: Zn: Zinc. 600 mg/kg, respectively.

Volume 22 Issue 6 (2025) 175 doi: 10.36922/AJWEP025140101