In vitro grafting procedure for facilitating growth of separated shoots in castor

Abstract

Regenerated adventitious buds in an Agrobacterium-mediated genetic transformation system of castor (Ricinus communis L.) are difficult to develop in intact plants.Therefore, an in vitro grafting system in castor was established in this study. The stocks and scions were obtained from castor seedlings, and complete castor plants could be gained by in vitro grafting. To promote growth of grafted seedlings, the effects of indole 3-butyric acid (IBA), 6-benzyl aminopurine (6-BA), kinetin (KT), sodium nitrophenolate (SN), and diethyl aminoethyl hexanoate (DA-6) on the development of grafted seedlings were explored. The experimental results indicated that when adding IBA, KT, and SN to the media at concentrations of 0.1, 0.2, and 0.8 mg L −1 , respectively, the growth of castor grafted seedlings could be promoted strongly; however, when 6-BA or DA-6 was added to media, the growth and development of castor grafted plantlet were inhibited significantly. Moreover, the survival rate of transplantation of grafted seedlings was up to 74.5%. The method of in vitro grafting in castor could be used to obtain robust and complete castor plants quickly and might provide a solution to the problems of adventitious bud growing and rooting difficulty in the genetic transformation of castor.

An Efficient and Rapid Protocol for Somatic Shoot Organogenesis from Juvenile Hypocotyl-Derived Callus of Castor Bean cv. Zanzibar Green

“…In vitro shoot regeneration via both direct and indirect organogenesis was achieved on culture medium containing different types and concentrations of cytokinins such as TDZ [ 20 , 22 , 26 ], zeatin [ 18 , 23 ], 6-BAP [ 25 ], kinetin [ 25 ], and 2iP [ 27 ] alone or in combination with a low concentration of auxin (IAA [ 23 , 25 ] or 1-naphthylacetic acid (NAA) [ 22 , 25 ]). Some authors propose to simultaneously combine two cytokinins in the shoot induction medium for improving regeneration capacity, for example, BAP and kinetin [ 21 , 24 , 33 ] or BAP and TDZ [ 18 ]. The application of 15 mg/L glutamine [ 22 ] and gibberellic acid [ 19 , 21 , 22 ] was also recommended as additional culture medium components for the formation and elongation of regenerants.…”

“…In contrast, Zalavadiya et al (2014) did not achieve rooting of shoots on RIM containing IAA, IBA, and AgNO 3 singly or in combinations even after 30 days of culture [ 21 ]. As an alternative, an in vitro grafting procedure has been developed for the rooting of regenerants and subsequent efficient adaptation of plantlets to soil conditions [ 33 ]. In the current study, we successfully induced rhizogenesis in shoots regenerated from juvenile hypocotyl-derived callus tissue on the RIM, both without PGRs and supplemented with 1 mg/L IBA.…”