TITLE:
Micropropagation and Acclimatization of Common Oregano (Origanum vulgare L. Subsp. vulgare) by Shoot Tip Culture
AUTHORS:
Rajae Benkaddour, Naouar Ben Ali, Ouafaa Hamdoun, Alain Badoc, Latifa Azaroual, Patrick Martin, Ahmed Lamarti
KEYWORDS:
Auxins, Cytokinins, Gibberellic Acid, Macronutrients, Micropropagation, Polyamines, Origanum vulgare
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.13 No.6,
June
29,
2022
ABSTRACT: Origanum vulgare L. is a
commercially valued species with remarkable biological properties. It is
subject to over-exploitation practices that seriously threaten its
sustainability for future generations. Thus, micropropagation serves as a tool
for the protection and domestication of this species. In this study, we
established an in vitro vegetative
propagation protocol for Origanum vulgare. This is done through the
axillary bud technique by carrying out various tests. Six culture media (MS,
MSm, N30K, SD, SH and B5) were tested. Therefore, SD was chosen for
the following experiments. Seven cytokinins (adenine (Ad), N6-(2-isopentenyl)
(2ip), zeatin (Zeat), kinetin (Kin), benzyladenine (BAP), 1,3-diphenylurea
(DPU) and thidiazuron (TDZ) at 5 concentrations (0.44, 1.33, 2.22, 3.11 and
4.44 μM/L) were evaluated. Thus, Kin at 3.11 μM allowed high regeneration of vitroplants,
optimal elongation, total rooting of explants, maximum bud multiplication, and
absence of hyperhydric explants. In fact, the integration of auxins
(indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), and
1-naphthaleneacetic acid (NAA)) into the culture medium and their combinations
with 3.11 μM Kinetin contributed to the optimization of the root part. Thus, it
was improved in particular in the case of 3.11 μM Kin and 6.27 μM IBA. Three
polyamines (Putrescine, Spermidine and Spermine) at different concentrations
(1.134, 3.402, 5.67, 7.938 and 11.34 μM/L) combined at 3.11 μM Kin and 6.27 μM
IBA were tested. In fact, 1.304 μM putrescine was considered to be the most
suitable for in vitro culture of
explants, since it allowed optimal propagation of buds and roots, also a high
rate of regeneration and rhizogenesis. GA3 at 1.15 μM combined with
3.11 μM Kin and 6.27 μM IBA permitted maximum bud multiplication. The
acclimatization was carried out successfully using vitroplants showing good
foliar and root development. Thus, three months after acclimatization, the
seedlings were transferred into large pots under natural light and temperature
conditions. Almost all acclimatized plants developed flowers in the first year
between May and July.