Ploidy affects phytochemistry and micromorphology of Thymus persicus (Ronniger ex Rech.f.) Jalas: An in vitro investigation

• Published in: Biochemical systematics and ecology 2023-08, Vol.109, p.104684, Article 104684
• Main Authors: Tavan, Mansoureh, Bakhtiar, Ziba, Ghorbanpour, Mansour, Karimzadeh, Ghasem, Mirjalili, Mohammad Hossein
• Format: Article
• Language: English
• Subjects: Anatomy; Carvacrol; Essential oil; Tetraploid; Thyme; Thymol; Trichome
• ISSN: 0305-1978; 1873-2925
• DOI: 10.1016/j.bse.2023.104684

Thymus persicus (Ronniger ex Rech. f.) Jalas (Lamiaceae) is an endemic and valuable essential oil-bearing plant. Herein, the effect of ploidy level on both anatomical structure and essential oil composition was investigated. Leaves of in vitro-induced tetraploids had more glandular peltate, capitate, and elongated non-glandular trichomes compared to diploids. Gas chromatography-flame ionization detector (GC-FID), and GC–mass Spectrometry (GC-MS) techniques were employed to unravel chemicals in hydro-distilled essential oils from in vitro diploid, tetraploid, and mixoploid clones. Notably, 21, 27 and 17 compounds representing 97.0%, 96.9%, and 96.7% of the total essential oils were identified and quantified in diploids, tetraploids, and mixoploids plants, respectively. A wide chemical variability was observed so much so that thymol (32.8%), α-terpineol (26.4%), and carvacrol (6.2%) were the main constituent in diploids, while carvacrol (33.85%), δ-selinene (8.79%), ishwarone (8.23%), and octanoic acid (8.07%) were in tetraploids and mixoploids mostly accounted in δ-Selinene (21.26%), pogostol (13.92%), methyl thujate (10.94%), and (2E,6E)-farnesyl acetate (10.28%). To further underline the ploidy effects, it was observed a strong decrease in the contents of monoterpene hydrocarbons and oxygenated monoterpene hydrocarbons in tetraploids and myxoploids. The sesquiterpene hydrocarbons showed an inverse behaviour. •Ploidy level affects anatomical structure and the EOs constituents of Thymus persicus.•Tetraploids had more glandular and elongated non-glandular trichomes than diploids.•A total of 21, 27 and 17 compounds were quantified in EOs of diploids, tetraploids, and mixoploids, respectively.•The major constituents of EOs in diploids were thymol, α-terpineol and carvacrol.•Hydrocarbons and oxygenated monoterpenes were severely decreased in tetraploids and mixoploids.