Page 178 - AJWEP-22-6

Ehsan, et al.

tested. However, much of the existing research on this Two weeks after Zn application, plants were
genera has been conducted in non-soil media, such as harvested and separated into roots, stems, and leaves.
hydroponic systems, with limited information available Plant tissues were thoroughly washed with tap water,
on its performance in contaminated soils. Therefore, followed by repeated rinsing with deionized water.
it was important to evaluate the response of Lupinus Samples were then oven-dried at 70°C for 72 h to record
uncinatus—an understudied species within the same dry weight, ground to a fine powder, and subsampled
genus as L. albus—to varying soil Zn treatments. (0.1 g) for digestion with nitric perchloric acid. Zn
concentrations (mg/kg) in plant organs were quantified
2. Materials and methods using an atomic absorption spectrophotometer (Model
3110, Perkin-Elmer, USA).
A greenhouse pot experiment was conducted to evaluate Data were analyzed using one-way analysis of
the phytoremediation potential of L. uncinatus. Soil was variance, and Tukey’s test was applied for multiple
collected from the top 25 cm layer of an agricultural comparisons of means at a significance level of p<0.05.
field at San Pablo Ixayoc, State of Mexico, Mexico, and Homogeneity of variance was verified using Levene’s
analyzed for Zn concentration along with other physical test (p˃0.05). All statistical analyses were performed
and chemical properties (Table 1). Seeds of L. uncinatus using SAS software (version 9.1; SAS Institute, United
were also collected from the same site. States). 36
Plastic pots (15 cm diameter) were filled with Metal tolerance was calculated using Equation I:
5 kg of soil. Seeds were sown directly in the pots A
and germinated within 5–7 days. One week after X = B × 100 (I)
germination, seedlings were thinned to three plants per
pot. After 4 weeks of growth, plants were treated with Where A = mean dry weight of plants grown under
ZnCl at concentrations of 200, 400, and 600 mg/kg, Zn treatments, and B = mean dry weight of control
2
applied in 15 mL of deionized water. plants (no Zn treatment).
The pots were arranged in a randomized design under Accordingly, a tolerance index of 50% indicates that
normal greenhouse conditions. Average daytime and plants produced 50% of the optimum biomass relative
nighttime temperatures ranged between 25–29°C and to the control, which is considered the minimum
8–11°C, respectively. Pots were re-randomized 3 times acceptable biomass under toxic soil conditions. 37
during the experiment. Four replicates were established
per treatment (200, 400, and 600 mg/kg) and for the 3. Results and discussion
control (no Zn added only having background soil Zn
concentration of 65 mg/kg). Pots were irrigated with 3.1. Plant growth and dry matter yield
distilled water every 2–3 days to maintain 70% of field The dry matter yield of L. uncinatus plants after
capacity. Plant growth was assessed by measuring dry 2 weeks of exposure to varying Zn supply levels is
weight accumulation under each Zn treatment, while presented in Table 2. The roots, being in direct contact
Zn content and distribution in roots, stems, and leaves with the heavy metal and serving as primary sites of
were determined at harvest, which marked the end of toxic action, showed a significant decrease in dry matter
the experiment.
Table 2. Dry matter yield of Lupinus uncinatus
Table 1. Selected physical and chemical after 2 weeks of exposure to different zinc
characteristics of pot soil supply levels

Parameter Value Zinc supply Dry matter yield (g/pot)
pH 6.29 levels Shoot Root Plant
(mg/kg)
Electrical conductivity 0.16 dS/m Control 1.90±0.18 b 0.56±0.04 a 2.46±0.17 b
Organic matter 1.19% 200 3.29±0.27 a 0.31±0.02 b 3.60±0.26 a
Soil texture Sand (34%); silt (32%); 400 2.99±0.21 a 0.30±0.03 bc 3.29±0.21 a
clay (34%) a c c
Bulk density 1.13 Mg/m 3 600 3.36±0.31 0.32±0.02 3.68±0.30
Total zinc content 65 mg/kg Note: Values in the same column followed by different letters
differ significantly (p<0.05) according to Tukey’s test (n=4).

Volume 22 Issue 6 (2025) 172 doi: 10.36922/AJWEP025140101