Volume: 5, 2026
5th International PhD Students’ Conference at the University of Life Sciences in Lublin, Poland:
ENVIRONMENT – PLANT – ANIMAL – PRODUCT
Abstract number: P023
DOI: https://doi.org/10.24326/ICDSUPL5.P023
Published online: 22 April 2026
Optimizing melatonin treatment for surfactant stress in cucumber
Hanna Witoszek* and Małgorzata Reda
Department of Plant Molecular Physiology, Faculty of Biological Sciences, University of Wrocław, 6/8 Kanonia St., 50-328 Wrocław, Poland
* Corresponding author: hanna.witoszek@uwr.edu.pl
The escalating global water crisis is driving the search for sustainable water alternatives. Recycled greywater is a promising candidate. However, despite purification processes, it often still contains surfactants. These chemicals are increasingly recognized as environmental contaminants that negatively affect plant physiology and development. One of the most commonly used surfactants in the chemical industry is sodium methylcocoyltaurate (SMCT). Previous investigations into the effects of SMCT on cucumber (Cucumis sativus L.) have identified the inhibition of nitrate reductase (NR) activity, one of the main producers of nitric oxide (NO) in plants. Given the role of NO as a secondary messenger in plant stress responses, this study aimed to optimize the application of melatonin (MT), a known antioxidant and signaling molecule, to alleviate SMCT-induced damage. A systematic screening of SMCT concentrations (5, 10, 30, 50, and 100 mg/L) and MT doses (5–150 μM) was conducted to establish baseline physiological responses in roots and leaves. Furthermore, the timing of MT application to the medium was evaluated across two distinct regimes: long-term treatment (7 days) and short-term treatment (24 h). Plant health was assessed through fresh and dry weight measurements, while NO levels were quantified using the Griess colorimetric method and visualized via DAF-FM (4-amino-5-methylamino-2′,7′-difluorofluorescein diacetate) fluorescent staining.
The results indicated that while low concentrations of SMCT (5 and 10 mg/L) did not significantly alter plant NO levels or shoot biomass, concentrations of 30 mg/L and above triggered an increase in endogenous NO production in whole plants and reduced shoot biomass. In roots, however, fresh weight was reduced even at the lowest concentrations of SMCT, with the impact intensifying as the concentration increased. Regarding MT applications, different responses were observed based on duration of treatment. Long-term MT treatment (7 days) resulted in a reduction of fresh weight alongside moderately elevated NO levels. Conversely, short-term MT treatment (24 h) did not affect biomass parameters but induced a significant dose-dependent increase in NO concentrations. These findings provide a necessary baseline for understanding the physiological impacts of surfactants and melatonin, serving as a foundation for future research into their interactive effects and potential for stress mitigation.
The source of funding: Minigrants for Doctoral Students of the University of Wrocław under the “Excellence Initiative – Research University (IDUB)” Program, grant number: BPIDUB.4610.311.2025.
Keywords: melatonin; nitric oxide; surfactant
How to cite
Witoszek H., Reda M., 2026. Optimizing melatonin treatment for surfactant stress in cucumber. In: 5th International PhD Students’ Conference at the University of Life Sciences in Lublin, Poland: Environment – Plant – Animal – Product. https://doi.org/10.24326/ICDSUPL5.P023