Micropropagation of the Moroccan Endemic Plant <i>Thymus broussonetii</i> Boiss. with Aromatic-Medicinal Value and Conservation Concern

Abstract

Micropropagation from shoot tips and nodal segments was carried out for the conservation and domestication of spontaneous Moroccan thyme, Thymus broussonetii Boiss. subsp. broussonetii (endemic threatened). The mineral composition of the culture medium, as well as the succession of different growth regulators, influenced the in vitro growth of this species. Sterilized achenes of T. broussonetii were able to germinate on an agar medium containing Gautheret macronutrients with a rate of 25% and a degree of contamination of less than 4%. Shoot apices of 15-day seedlings (two cotyledon leaves) were cultivated on SD + 0.46 μM Kin medium and the explants obtained were transplanted every month. Six macronutrients (MS, B 5 , SH, SD, MS m and N 30 K) were tested and N 30 K was chosen for the following experiments. Seven cytokinins (Kin, BAP, 2iP, DPU, adenine, Zeat and TDZ) at 0.46, 0.93 and 2.32 µM/l were evaluated and the addition of 0.93 µM adenine to N 30 K medium favored significantly the induction of buds and the elongation of explants. Three polyamines (putrescine, spermidine and spermine) at 2, 5, 10 and 20 µM/l were tested. A better multiplication of buds, shoots and roots was noted for N 30 K + 10 µM spermine. Cytokinin-auxin combinations led to better root multiplication and an increase in the number of buds and the length of explants, particularly for 0.46 µM Kin + 2.85 µM IAA. Acclimatization was successfully carried out using vitroplants developing a good root system.

Micropropagation and Acclimatization of Common Oregano (<i>Origanum vulgare</i> L. Subsp. <i>vulgare</i>) by Shoot Tip Culture

“…The study of the effect of polyamines alone or in combination with cytokinins or/and auxins has been addressed in investigations of other species belonging to the Lamiaceae family. El Ansari et al (2020) [35] showed that medium supplemented with 10 µM Spermine gave the best results in terms of bud, shoot and root multiplication, and Sarropoulou and Maloupa (2019) [36] showed that the integration of exogenous polyamines contributed to numerous modifications in the growth of Sideritis raeseri Boiss. & Heldr.…”

Interaction Effect of Plant Growth Regulators on Shoot Micropropagation of Aromatic Plant <i>Origanum elongatum</i> (Bonnet) Emberger & Maire

“…In addition, Kizil and Khawar (2017) [35] reported that the proliferation and regeneration of Origanum acutidens shoots was maximal in medium supplemented with 0.8 µM BAP. Moreover, the type and concentration of cytokinins were evaluated in other species of the Lamiaceae family ( [36] [37] [38] [39]).…”

“…Application of polyamines alone, including spermine and spermidine at concentrations greater than 10 µM, inhibits the root formation of Lavandula × intermedia "Grosso" vitroplants (Erland and Mahmoud 2014) [51]. El Ansari et al (2019) [36] found that the best propagation of buds, shoots and roots of Thymus vulgaris L. was marked in the medium supplemented with 10 µM spermine and demonstrated that 50 µM spermidine was effective for better propagation of roots whereas 10 µM of the same polyamine was favorable for root propagation.…”