In vitro regeneration of Carlina acaulis subsp. simplex from seedling explants

Abstract

The aim of the study was to obtain an efficient system for Carlina acaulis subsp. simplex propagation. The experimental materials were shoot tips, fragments of hipocotyls, cotyledons and roots isolated from 10-day-old seedlings. The explants were transferred to the proliferation medium supplemented with different types of cytokinin: BA (13.3 lM), kinetin (13.9 lM) and zeatin (13.7 lM) in combination with NAA (0.54 lM). The best morphogenetic response was observed when explants were cultured on the BA supplemented medium. The maximum shoot organogenesis frequency was observed for shoot tip (nearly 94%). On average 8.6 axillary shoots were induced per explant. Multiplication rate increased during the first three subcultures. The shoots revealed a wide range of morphogenetic responses. Differences were observed in the presence or absence of hair on the surface of lamina. These changes had epigenetic character and were the effect of changes in DNA methylation, which is shown by differences in methylation pattern between 18S rRNA and 25S rRNA genes in the analyzed regenerated plants. Nearly 94% of plantlets were rooted on auxin lacking medium. Addition of auxin (NAA or IAA) increased both the rooting percentage (100%) and the number of roots per shoot, but their growth was inhibited. Shortening of the auxin exposition time reduced the number of roots. Moreover, high efficiency (90%) was observed for ex vitro rooting. Plantlets with a large number of roots survived better than the ones with only a few roots. Plants were able to flower and gave viable seeds.

Shoot Multiplication and in Vitro Rooting of Carlina onopordifolia Basser

“…1). Similar results have been reported from studies in Carlina acaulis (Trejgell et al, 2009) and other Asteraceae species (Joshi and Dhar, 2003;Baskaran and Jayabalan, 2005;Trejgell et al, 2010). The presence of auxin was necessary for induction of roots on C. onopordifolia shoots (Tab.…”

“…Earlier studies of regeneration in the genus Carlina used C. acaulis. In that case, propagation was reported to be most effective from zygotic embryos (Grubisić et al, 2004) and shoot tips (Trejgell et al, 2009). …”

Micropropagation of Senecio Macrophyllus M. Bieb

“…The multiplication rate was highest (8.3 ± 1.0) for explants treated with 4.4 μM BA. These results are in conformity with earlier reports for Senecio × hybridus (Gertsson, 1988) and other plants of the Asteraceae family, such as Tagetes erecta (Misra and Dutta, 1999), Wedelia calendulacea (Emmanuel et al, 2000), Echinacea purpurea (Korach et al, 2002), Eclipta alba (Dhaka and Kothari, 2005) and Carlina acaulis (Grubisić et al, 2004;Trejgell et al, 2009), where the highest multiplication rate was achieved with BA-supplemented MS medium. In subsequent subcultures of S. macrophyllus the number of shoots per explant decreased (Fig.…”

“…1b). Similar results have been described for other species of the Asteraceae family (Joshi and Dhar, 2003;Baskaran and Jayabalan, 2005;Trejgell et al, 2009). BA at a concentration of 2.2 μM in combination with NAA at 0.27 μM caused limited inhibition of shoot elongation; average shoot length was 31.9 ± 1.6 mm (Tab.…”

“…2). Earlier studies have examined the rooting process on MS medium without auxin in many members of the Asteracae family: Guizotia abyssinica (Sujatha, 1997), Centaurea paui (Cuenca et al, 1999), Echinacea purpurea (Korach et al, 2002) and Carlina acaulis (Trejgell et al, 2009), as well as many other species. The incidence of root formation on auxin-free medium may be due to the presence of endogenous auxin in regenerated shoots (Minocha, 1987).…”