In Vitro Regeneration of Castor (Ricinus Communis L.) Using Cotyledon Explants

Abstract

<jats:p>An efficient plant regeneration protocol using cotyledon explants was established for castor (<jats:italic>Ricinus communis</jats:italic> L.), an important oilseed crop. Mature seed-derived cotyledon explants produced adventitious shoots when placed on Murashige and Skoog (MS) medium containing thidiazuron (TDZ). The rate of shoot regeneration was maximal (≈25 shoots per explant) when explants were cultured on shoot induction medium supplemented with 5 μ<jats:sc>m</jats:sc> TDZ and preincubated in the dark for the first 7 days before transferring to the day/night cycle (16/8 h). Only the proximal ends of cotyledon explants produced adventitious shoots, although green calli were observed in cotyledon veins. After 4 weeks in culture, explants with well-developed shoot buds were transferred to MS medium without plant growth regulators for the shoot elongation and development. At ≈4 months after culture initiation, shoots (2 cm in length) were transferred to root induction medium (MS medium supplemented with 5 μ<jats:sc>m</jats:sc> indole-3-butyric acid) where they developed roots in 4 to 6 weeks. Plantlets were transferred to soil and acclimatized to greenhouse conditions. Histological analysis showed the adventitious induction of the shoots originated from the cortical and epidermal cell layers of the cotyledon explants.</jats:p>

In Vitro Plant Regeneration of Andrographis Paniculata Nees Using Mature Zygotic Embryonic Explants

“…Shoot initials arose from the bulging in the cotyledons and from the apical region of the embryonal axes within 15 days of dark incubation. This observation indicates the necessity of exposure of the explants to dark period for the initial induction of shoot formation as was earlier reported for Zizyphus jujube [24] and Ricinus communis [19]. The chief characteristic of tissues grown in dark is preservation of light-sensitive endogenous or exogenous plant growth regulators [25].…”

“…Embryonic explants have been used for micropropagation and genetic transformation [13]. Direct shoot regeneration has been reported in many plants from zygotic embryo explant in Boscia Senegalensis [14], Cajanus cajan [15], from decapitated embryonic axes in Cicer arietinum [16], Clitoria ternatea [17] and cotyledons in Benincasa hispida [18] and Ricinus communis [19].…”

The root endophytic bacterial community of Ricinus communis L. resembles the seeds community more than the rhizosphere bacteria independent of soil water content

“…Collected roots and seeds were washed with sterile water, soaked in ethanol for 5 min and disinfected with 2.5% sodium hypochlorite for 15 min and rinsed with sterile water 65 . The root (1.5 g from each sampled plant) and seeds (1.5 g in triplicate) were macerated with liquid nitrogen to a fine powder.…”

Role of conventional and biotechnological approaches in genetic improvement of castor (Ricinus communis L.)

“…Studies on in vitro callus production from hypocotyl segments of castor revealed genotype specific hormone combination requirement for the production of friable callus reported shoot bud proliferation from embryo axis and shoot tip explants with up to 100% shoot proliferation with 22-81 shoots per explants on different concentration of BAP and thidiazuron (TDZ) (Khumsub, 1988;Sangduen et al, 1987;Molina and Schobert, 1995;Sujatha and Reddy, 1998). Induction of adventitious shoot buds originated from the epidermal and cortical cell layers of the cotyledon explants (Ahn and Chen, 2008). Application of TDZ for shoot induction and indole-3-butyric acid (IBA) for root induction has also been clearly demonstrated.…”