Thesis Abstract

This study was carried out on the nutrient requirements for the in vitro propagation of Ricinus communis employing the basal media of Murashige and Skoog (1962), Gamborg et al. (1968), and Schenk and Hildebrandt (1972) using zygotic embryos as explants. Zygotic embryos were excised from mature seeds and cultured on the three basal media with 3 per cent sucrose and 8 g/l of agar. Plant growth regulators were not added to the media. This study was done to determine the most suitable basal medium for the growth of R. communis zygotic embryo. The results obtained showed that the three basal media employed supported in vitro regeneration of the embryo explants. The highest mean shoot length (4.450±0.231 cm), the highest mean root length (2.190±0.262 cm), highest mean fresh weight (0.365±0.032 g), highest mean leaf area (1.999±0.189 cm2), highest mean per cent sprouting (91.660±0.000), and highest mean number of roots (4.600±0.163) were observed on Murashige and Skoog medium whereas the highest mean sprout rate (0.330±0.000) was obtained on Murashige and Skoog and Gamborg et al. media. The embryo explants were able to develop into normal plantlets even in the absence of growth regulators. This may suggest that endogenous hormones in the zygotic embryo were present at an optimal level to support regeneration. Results from this study indicated that Murashige and Skoog basal medium was the best basal medium for the in vitro propagation of Ricinus communis zygotic embryo. The results are discussed in the light of its potential for mass production of Ricinus communis for its economic values.

Thesis Overview