Benita Kalicharan
Title: Micropropagation and micro-morphological studies of Stachys natalensis Hochst.
Biography
Biography: Benita Kalicharan
Abstract
Stachys is one of the largest genera in the family Lamiaceae with many members being used as ornamentals, edible food sources and as therapeutic agents in traditional medicine. Stachys natalensis Hochst., is a perennial, straggling shrub found in grassy and woody areas along the east coast of southern Africa. This study was undertaken to describe key micro-morphological features of the foliar structures of S. natalensis and establish an in vitro micropropagation protocol for the sustained and high-yielding production of this difficult to cultivate species. Furthermore, the foliar micro-morphological fidelity between field and in vitro propagated material was compared. Successful decontamination of axillary bud explants involved immersion in 1 % and 3 % NaClO, followed by 0.1 % HgCl2. Bud break was achieved within 3 weeks on MS media supplemented with benzylaminopurine (BAP) and indole-3-butyric acid (IBA). Shoot multiplication (9.1 ± 3.6 shoots/explant) was achieved in media containing kinetin and indole-3-acetic acid (IAA) after 12 weeks. The addition of IAA to MS medium allowed for 64 % of shoots to produce adventitious roots in 5 weeks, after which rooted plants were acclimatized. Acclimatized plantlets (92 ± 4.2 %) did not show any gross morphological abnormalities compared to field-grown plants, apart from the presence of visibly longer non-glandular trichomes. Glandular trichomes of acclimatized plants were morphologically similar to their field-grown counterparts. Trichome density of micro-propagated plants decreased with leaf maturity, as observed on field-grown plants. With an effective in vitro propagation protocol presently established, further optimization is required for enhanced plantlet production.