Induction of Indirect Somatic Embryogenesis on Embryonic Axis of TRI2025 Tea Clone

Abstract

Tea (Camellia sinensis L.) is classified as cross-pollinated crop and vegetative multiplication becomes commercially the main method of propagation with some limitations such as high heterogeneity and poor in survival rate and also in rooting. A proven tissue culture method, somatic embryogenesis, is the only challenging way to meet the needs of tea seedlings in large quantities. The study was conducted with TRI2025 tea clone selected from Polyclonal garden of PT. Pagilaran (Batang, Central Java). The explants were cultured on MS media supplemented with four concentrations of 2,4-D (0, 1, 2, and 5 mg L-1) in two incubation conditions; dark and light. The results showed the only concentration of 2,4-D that can induce somatic embryo was 2 mg L-1 2,4-D in light condition and its percentage was about 5%. Other concentrations of 2,4-D that given for treatments both in two conditions will not induce somatic embryo. This study needs more improvements for getting powerful and efficient of method to get somatic embryo-derived plant and also for futher successful genetic engineering of tea biotechnology.

Morphological, Histological, and Protein Profiling of Tea Embryo Axis at Early Stage of Culture

“…The unique thing that only happened to almost explants cultured on A medium was the visible globular-like structure; a slightly transparent white near the shoot meristem (Figure 1C, white cycle). This transparent globularlike structure was the main differentiator of explants cultured on A medium and this phenomenon had been reported (Eskundari et al 2018). It was likely that this globular-like structure was the result of the presence of 54 kDa and 81 kDa protein.…”

“…This removed growth points of axis embryo later to be cultured on two different induction media; somatic embryogenesis and in vitro organogenesis induction medium (or called by A and B medium, respectively). The A medium was MS medium added with 2 mg L -1 of 2,4-D (Eskundari et al 2018) and the other was ½ MS media added with 2 mg L -1 of BAP (according to our best result of preliminary study). Both of these media were adjusted to 5.6 of pH prior to autoclaving.…”

“…One alternative choice of its vegetative propagation is through tissue culture, both somatic embryogenesis or in vitro organogenesis. There have been many reports that provided information about the success of tea propagation, with different culture conditions, such as differences in plant growth regulators (PGRs), incubation time, and other tissue culture conditions (Seran et al 2006;Kaviani 2013;Gonbad et al 2014;Eskundari et al 2018).…”

“…One crucial point is the root-apical axis development that only occurs at explants induced through somatic embryogenesis (Bassuner et al 2006). In tea, there were many reports about somatic embryogenesis and in vitro organogenesis using different clones (Gunasekare & Evans 2000;Sandal et al 2005;Seran et al 2006;Kaviani 2013;Gonbad et al 2014), and TRI2025 tea clone has been reported for source clone of various explants; through both techniques (Akula & Dodd 1998;Seran et al 2006;Eskundari et al 2018). Besides specific clone requirements, successful of somatic embryogenesis and in vitro organogenesis also require specific PGRs to promote the explant's growth and development.…”

“…Its role related to somatic embryogenesis (also to zygotic embryogenesis) is well correlated with its capability to induce cell expansion, cell cycle, and morphogenesis in plant tissue culture (Raghavan 2004). Especially in tea's tissue culture, 2,4-D is usually added to the culture medium to induce somatic embryogenesis, either by callusing pathway or directly (Kaviani 2013;Eskundari et al 2018).…”