Biostimulants enhance phenolic and volatile accumulation in common thyme under mild salinity stress

Zamljen, Tilen (author), Adamič Zamljen, Sergeja (author), Grohar, Mariana Cecilia (author)

Common thyme (Thymus vulgaris L.) is a widely cultivated aromatic herb that is valued for its high content of phenolic and volatile compounds, which contribute to its nutritional and sensory quality. A range of agronomic strategies have been investigated for the purpose of enhancing the quality of common thyme, including the implementation of mild abiotic stress. In this study, mild salinity stress was combined with four biostimulants to evaluate their effects on the phenolic and volatile profiles of common thyme. The identification of 14 phenolic compounds and 32 volatile compounds was achieved through the utilisation of HPLC-MS and GC-MS analysis, respectively. Salinity exhibited a significant effect on the total phenolic content, with a marked increase in comparison with the control. The incorporation of biostimulants served to augment phenolic accumulation, with Protifert® LMW exhibiting the most pronounced effect, resulting in an escalation of the total phenolic content by 44–98% relative to the control. It was established that rosmarinic acid and luteolin-3-O-glucuronide were the most responsive compounds. Concurrently, the volatile profile exhibited a substantial response to biostimulant application. The Delfan Plus and Protifert® LMW treatments resulted in the highest total volatile contents, with Delfan Plus reaching 167.31 mg kg-1 FW, corresponding to increases of 129% and 52% compared with saline and non-saline conditions, respectively. Overall, mild salinity stress modulated phenolic and volatile metabolism in common thyme, while selected biostimulants enhanced metabolite accumulation. These findings underscore the efficacy of integrating controlled salinity stress with biostimulant application as a strategy to enhance the phytochemical quality of common thyme.

• Language: English
• Keywords: Thymus vulgaris, biostimulants, salinity stresss, phenolic compounds, volatile compounds, HPLC-MS, GC-MS, secondary metabolism
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: 9 str.
• Numbering: Vol. 362, art. 14889
• PID: 20.500.12556/RUL-182622
• UDC: 635
• ISSN on article: 0304-4238
• DOI: 10.1016/j.scienta.2026.114889
• COBISS.SI-ID: 278609923
• Publication date in RUL: 19.05.2026

Record is a part of a journal

• Title: Scientia horticulturae
• Shortened title: Sci. hortic.
• Publisher: Elsevier
• ISSN: 0304-4238
• COBISS.SI-ID: 5191687

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: timijan, biostimulanti, slanostni stres, fenolne spojine, hlapne spojine, sekundarni metaboliti

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P4-0013
• Name: Hortikultura

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: IO-0022
• Name: Mreža raziskovalnih infrastrukturnih centrov Univerze v Ljubljani (MRIC UL)