Initiation of embryogenic cell suspensions of taro (Colocasia esculenta var. esculenta) and plant regeneration

Abstract

Embryogenic callus was initiated by culturing in vitro taro corm slices on agar-solidified half-strength MS medium containing 2.0 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) for 20 days followed by transfer to 1.0 mg/L thidiazuron (TDZ). Callus was subsequently proliferated on solid medium containing 1.0 mg/L TDZ, 0.5 mg/L 2,4-D and 800 mg/L glutamine before transfer to liquid medium containing the same components but with reduced glutamine (100 mg/L). After 3 months in liquid culture on an orbital shaker, cytoplasmically dense cell aggregates began to form. Somatic embryogenesis was induced by plating suspension cells onto solid media containing reduced levels of hormones (0.1 mg/L TDZ, 0.05 mg/L 2,4-D), high concentrations of sucrose (40-50 g/L) and biotin (1.0 mg/L). Embryo maturation and germination was then induced on media containing 0.05 mg/L benzyladenine (BA) and 0.1 mg/L indole-3-acetic acid (IAA). Histological studies of the developing embryos revealed the presence of typical shoot and root poles suggesting that these structures were true somatic embryos. The rate of somatic embryos formation was 500-3,000 per mL settled cell volume while approximately 60% of the embryos regenerated into plants.

Pretreatments, conditioned medium and co-culture increase the incidence of somatic embryogenesis of different Cichorium species

“…We have previously shown that AGPs are released in the culture medium of embryogenic and non-embryogenic chicories but no major difference in the soluble AGP profiles was detected. 33,38 We have also shown earlier that complexation of soluble AGPs with b-D Glc Yariv reagent inhibits mitosis while cell reactivation still occurs. 33,38 To test whether the difference in the ISE of the embryogenic hybrid and of the cv Pévèle was correlated with differences in the quantity of released AGPs, we determined the mean quantity of soluble AGPs Figure 1.…”

“…33,38 We have also shown earlier that complexation of soluble AGPs with b-D Glc Yariv reagent inhibits mitosis while cell reactivation still occurs. 33,38 To test whether the difference in the ISE of the embryogenic hybrid and of the cv Pévèle was correlated with differences in the quantity of released AGPs, we determined the mean quantity of soluble AGPs Figure 1. Effects of pretreatment of leaves of the embryogenic hybrid of Cichorium, with 0.5 mM polyamines (putrescine, spermidine, or spermine), of 330 mM glycerol,or of several concentrations of (± ) cis, trans abscisic acid (ABA), on the number of somatic embryos (mean ± SEM for n = 9 independent experiments).…”

“…6,31,32 Addition of other osmotica, such as mannitol or sucrose, was also shown to promote SE (Colocasia esculenta, Cucumis melo, Cucumis sativus, Eleutherococcus sentocosus, Pinus taeda, Saccharum officinarum, or androgenesis (wheat). 22,[33][34][35][36][37][38] The high osmolarity in the culture medium can also be a consequence ABA is a plant growth regulator often associated with totipotency and its endogenous concentration should be low to promote SE in Daucus carota, Medicago or Nicotiana 14,40-42 while it should be high to promote SE in other models (Cucumis melo, Daucus carota, Pennistum purpureum). 34,43,44 Exogenous addition of ABA led to improve the ISE in monocots (Cocos nucifera, Cynodon hybrid Musa sp.)…”

Induction of somatic embryogenesis in gum arabic tree [Acacia senegal (L.) Willd.]

“…Means in each column followed by different letters are significantly different according to DMRT at P<0.05 1997) and enhances the synthesis of certain metabolites (Deo et al 2010). Earlier, the beneficial role of Lglutamine in the induction of somatic embryogenesis has also been reported in a number of studies (Garin et al 2000;Robichaud et al 2004;Zouine and Hadrami 2007;Deo et al 2010).…”

“…Means in each column followed by different letters are significantly different according to DMRT at P<0.05 1997) and enhances the synthesis of certain metabolites (Deo et al 2010). Earlier, the beneficial role of Lglutamine in the induction of somatic embryogenesis has also been reported in a number of studies (Garin et al 2000;Robichaud et al 2004;Zouine and Hadrami 2007;Deo et al 2010). In contrast to our observations, insignificant role of L-glutamine in somatic embryogenesis was also reported in Acacia catechu (Rout et al 1995), Prunus incise (Cheong and Pooler 2004), Psidium guajava (Rai et al 2009).…”