Somatic embryogenesis from cultured mature cotyledons of cassava (Manihot esculenta Crantz)

Abstract

Somatic embryogenesis was obtained from mature cassava cotyledons explants. A two-step medium sequence was developed for efficient embryogenesis. Application of 2,4-D (4 mg 1-1) yielded proembryogenic masses which developed into somatic embryos after transfer to a medium containing NAA (0.01 mg l-t), BA (0.1 mg l -l) and GA3 (0.1 mg 1-l). The 2,4-D concentrations used for embryo initiation strongly influenced embryo development. Among the cultivars tested, TMS 30395 was most responsive. Full strength MS basal medium alone or with 4 x MS micro salts was efficient for the formation of somatic embryos. Casein hydrolysate, adenine sulfate, nicotinic acid, glycine, tryptophan, and serine were ineffective for embryo development. High sucrose concentration (6%, w/v) inhibited the induction of somatic embryos, while 6% sucrose was optimal concentration for the development of somatic embryos after an induction treatment using 2% sucrose. Addition of 0.52 mg 1-1 ABA to the induction media resulted in an increase in somatic embryos production. The ploidy levels of the regenerated plantlets were determined by flow cytometry analysis. Fifty regenerants tested were all tetraploids as the source plants and were morphologically normal. The implications of these results are discussed in relation to genetic transformation using the cotyledons as the explant source.

Somatic embryogenesis from callus cultures of Terminalia chebula Retz.: an important medicinal tree

“…In contrast it has also been found that higher concentrations of sucrose in the medium did not improve somatic embryo maturation in hybrid chestnuts (Vieitez 1995). Higher concentrations of sucrose were optimal for the development of somatic embryos in Manihot esculenta (Konan et al 1994). The effects of high sucrose concentrations in the maturation medium may have resulted from high osmolarity, which has been used to prevent precocious embryo germination, and enhance embryo maturation in some other plant species (PliegoAlfaro et al 1996).…”

“…The effects of high sucrose concentrations in the maturation medium may have resulted from high osmolarity, which has been used to prevent precocious embryo germination, and enhance embryo maturation in some other plant species (PliegoAlfaro et al 1996). ABA has been used in maturation media to improve synchronisation, and conversion of somatic embryos in to plantlets (Konan et al 1994;Kumari et al 1998;Xing et al 1999). However, in the present study ABA did not help in the maturation of somatic embryos.…”

Plant regeneration via somatic embryogenesis of Camptotheca acuminata in temporary immersion system (TIS)

“…In species such as Solanum melongena and Medicago sativum 2-3% sucrose was enough to achieve somatic embryos (Meijer and Brown 1987). Conversely, high levels of sucrose (6%) were reported to inhibit the induction of somatic embryos (Konan et al 1994). Cunha and Fernandes-Ferreira (1999) also reported that a low concentration of 2% sucrose was much more effective for the induction of somatic embryos than 4% which shows a decrease of about 50%.…”

Relationship between auxin-induced cell proliferation and somatic embryogenesis in culture of carrot cotyledons

“…Therefore, cotyledon morphology of somatic embryos may be affected by the duration of the 2,4-D treatment. In other studies, somatic embryogenesis, such as in young leaves of cassava, was inhibited when they were cultured on a medium with a higher concentration of 2,4-D (12 mg/L; Konan et al, 1994). Likewise, somatic embryogenesis from soybean explants on a medium containing 10 mg/L 2,4-D was arrested at the globular stage (Choi et al, 1994).…”

“…For example, *Corresponding author; fax +82-63-270-3362 e-mail showy@moak.chonbuk.ac.kr cotyledon development in soybean embryos was arrested when they were produced on a medium containing a high concentration of 2,4-D (Choi et al, 1994). Likewise, thestructural abnormality of somatic embryos depended on the concentration and period of 2,4-D treatment in the medium (Konan et al, 1994). Cotyledon abnormality in Aralia cordata was induced during long-term culture on a medium with 2,4-D (Lee and Soh, 1993a).…”