Influence of growth regulators on somatic embryogenesis, plantlet regeneration, and post-transplant survival of Echinochloa frumentacea
1992
Sankhla, A. | Davis, T.D. | Sankhla, D. | Sankhla, N. | Upadhyaya, A. | Joshi, S.
After placement on Murashige and Skoog's basal medium supplemented with 3-5 mg/l 2,4-D, immature inflorescence explants of Echinochloa frumentacea gave rise to three distinct types of callus: a) loosely arranged and soft; b) compact and translucent; c) compact, sticky and mucilaginous. Somatic embryo formation occurred in type 'b' callus in about 18-24 d. Callus types 'a' and 'c' did not produce somatic embryos. The highest percentage of cultures exhibiting somatic embryogenesis occurred on the medium containing 5 mg/l 2,4-D and 0.5 mg/l kinetin. Somatic embryos also formed directly on the inflorescence (without intervening callus formation) in about 15% of the explants placed on this medium. The addition of paclobutrazol or uniconazole (0.25 or 1 mg/1) to the medium had no influence on the percentage of cultures exhibiting direct somatic embryogenesis, but paclobutrazol slightly increased the mean number of somatic embryos per culture. Many of the callus-derived somatic embryos germinated when subcultured on basal MS medium supplemented with kinetin. Addition of paclobutrazol or uniconazole to the culture medium at 0.25 or 1 mg/l decreased somatic embryo germination and shoot elongation but increased root length and leaf width. Both paclobutrazol and uniconazole increased survival of the plantlets following transplanting to soil. Increased post-transplant survival was accompanied by reduced water loss from plantlets produced on culture media containing triazoles.
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