. Department of Biology, PMAS-Arid Agriculture University, Rawalpindi, Punjab 46300, Pakistan . Department of Botany, PMAS-Arid Agriculture University, Rawalpindi, Punjab 46300, Pakistan . Department of Botany, Government College Women University, Sialkot 51310, Pakistan . Krishi Vigyan Kendra Dhalai, Tripura 799278, India . Department of Biological Sciences and Chemistry, College of Arts and Science, University of Nizwa, Nizwa 616, Sultanate of Oman . Department of Botany & Microbiology, College of Science, King Saud University, Riyadh 11495, Saudi Arabia
Polyethylene-based plastic mulch films are widely utilized in agriculture due to their benefits in improving soil conditions and crop yield. However, their degradation into microplastics has been shown to negatively impact plant growth and development, posing a significant source of plastic pollution in the agroecosystem. In response to this issue, the present study aimed to design an innovative bioremediation system based on PGPR (Pseudomonas aeruginosa), biochar, and UV treatment for the degradation of plastics. Additionally, the phytotoxic effects of plastic residues on the growth of Spinacia oleracea (spinach) were evaluated to understand the impact of plastic contamination on plant health. Bacterial strains were isolated from vegetable-cultivated soil with plastic mulch. The bacterial strain demonstrating the most effective plant growth-promoting properties and plastic degradation efficiency was identified as Pseudomonas aeruginosa (OP007126). Biochar was prepared from food waste and thoroughly characterized. Polyethylene (PE) was exposed to UV radiation to induce degradation. A glass house experiment was then designed to assess the effect of PGPR, biochar, and UV radiation on mitigating plastic-induced stress and promoting plant growth. Fourier transform infrared spectroscopy (FTIR) and weight loss measurement showed a maximum degradation of 62% with a combination of all treatments. PE negatively affected the morphology of the plant as it decreased the shoot and root fresh weight by up to 60%. Biochemical parameters of spinach were also affected by PE, as proline content increased by up to 45%. The use of amendments demonstrated effectiveness in alleviating the detrimental impact of PE on spinach plants, as evidenced by improvements in morphological, physiologic, and biochemical parameters. This approach presents a promising strategy to mitigate the detrimental effects of plastic mulch and warrants further investigation through field trials.
Nageen Bostan,Noshin Ilyas,Maimona Saeed, et al. An in vitro phytotoxicity assessment of UV-enhanced biodegradation of plastics for spinach cultivation[J]. Front. Environ. Sci. Eng.,
2025, 19(2): 17.
Tab.1 Effect of amendments (Pseudomonas aeruginosa, Biochar and UV) on weight reduction of MPs PE
Soil amendments
Electrical conductivity (mS/cm)
pH
Texture
Moisture content (%)
Control
0.41 ± 0.01h
8.620333 ± 0.010017g
Sandy clay loam
18 ± 1i
Microplastic polyethylene (MPs PE)
0.184333 ± 0.00152g
8.723333 ± 0.015275f
Sandy clay loam
11.7 ± 0.1h
MPs PE + Biochar
0.220333 ± 0.01050f
8.630333 ± 0.010504h
Sandy clay loam
12.43667 ± 0.148436f
MPs PE + UV
0.250333 ± 0.01050e
8.670333 ± 0.009504
Sandy clay loam
12.13333 ± 0.152753g
MPs PE + Psedomonas aeruginosa
0.213333 ± 0.00577i
8.613333 ± 0.015275e
Sandy clay loam
14.13333 ± 0.11547e
MPs PE + Biochar + UV
0.280333 ± 0.00950d
8.403333 ± 0.195021e
Sandy clay loam
15.56667 ± 0.321455c
MPs PE + Biochar + Pseudomonas aeruginosa
0.306667 ± 0.01527c
8.680333 ± 0.010504a
Sandy clay loam
15.33333 ± 0.057735d
MPs PE + UV + Pseudomonas aeruginosa
0.320333 ± 0.01050b
8.660333 ± 0.010504b
Sandy clay loam
16.3 ± 0.173205b
MPs PE + Biochar + UV + Psedomonas aeruginosa
0.370333 ± 0.01001a
8.613667 ± 0.006351c
Sandy clay loam
17.56667 ± 0.152753a
Tab.2 Analysis of soil physiochemical attributes
Soil amendments
Nitrogen (%)
Phosphorous (ppm)
Potassium (ppm)
Organic matter
Control
0.092067 ± 0.000902i
4.803333 ± 0.1054a
9.803333 ± 0.095044a
28.03333 ± 1.050397h
Microplastic polyethylene (MPs PE)
0.047067 ± 0.00095h
2.706667 ± 0.110151h
6.12 ± 0.01i
27.03333 ± 1.050397f
MPs PE + Biochar
0.057133 ± 0.00115f
3.303333 ± 0.10504g
7.703333 ± 0.100167h
27.03333 ± 0.950438g
MPs PE + UV
0.05 ± 0.001g
2.37 ± 0.459021f
7.403333 ± 0.10504g
30.03333 ± 1.001665e
MPs PE + Psedomonas aeruginosa
0.066033 ± 0.001002d
3.503333 ± 0.100167d
7.603333 ± 0.430155f
29.3333 ± 1.527525a
MPs PE + Biochar + UV
0.061033 ± 0.00105e
3.203333 ± 0.95044e
7.703333 ± 0.10067e
27.36667 ± 1.517674d
MPs PE + Biochar + Pseudomonas aeruginosa
0.071733 ± 0.001617c
4.403333 ± 0.10504c
8.303333 ± 0.10504d
29 ± 2.645751b
MPs PE + UV + Pseudomonas aeruginosa
0.075033 ± 0.00095b
4.603333 ± 0.100167b
8.603333 ± 0.100167c
28.03333 ± 1.001665c
MPs PE + Biochar + UV + Psedomonas aeruginosa
0.094033 ± 0.001002a
4.603333 ± 0.430155b
9.403333 ± 0.10504b
29.33333 ± 1.527525 a
Tab.3 Analysis of soil nutrient attributes
Fig.1 Effect of amendments (Psedomonas aeruginosa, biochar, and UV on morphological parameters of Spinacea oleracea) (a) shoot length, (b) root length, (c) shoot fresh weight, (d) root fresh weight.
Fig.2 Effect of amendments (Psedomonas aeruginosa, biochar, and UV on morphological parameters of Spinacea oleracea) (a) shoot dry weight, (b) root dry weight, (c) leaf area.
Fig.3 Effect of amendments (Psedomonas aeruginosa, biochar, and UV on physiological parameters of Spinacea oleracea) (a) relative water content, (b) membrane stability index.
Fig.4 Effect of amendments (Psedomonas aeruginosa, biochar, and UV on physiological parameters of Spinacea oleracea) (a) chlorophyll a content, (b), chlorophyll b content, (c) total chlorophyll content, (d) carotenoid content.
Fig.5 Effect of amendments (Psedomonas aeruginosa, Biochar and UV on Biochemical parameters of Spinacea oleracea) (a) proline content, (b) protein content, (c) free amino acid content, (d) soluble sugar content.
Fig.6 Effect of amendments (Pseudomonas aeruginosa, biochar, and UV on antioxidant enzyme assay of Spinacea oleracea) (a) superoxide dismutase activity, (b) peroxidase activity, (c) catalase activity.
Fig.7 Heatmap showing the correlation coefficient between different treatments.
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