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A new and rapid protocol for optimum callus production and complete plant regeneration has been assessed in Malaysian upland rice (Oryza sativa) cv. Panderas. The effect of plant growth regulator (PGR) on the regeneration frequency of Malaysian upland rice (cv. Panderas) was investigated. Mature seeds were used as a starting material for callus induction experiment using various concentrations of 2,4-D and NAA. Optimal callus induction frequency at 90% was obtained on MS media containing 2,4-D (3 mg L(-1)) and NAA (2 mg L(-1)) after 6 weeks while no significant difference was seen on tryptophan and glutamine parameters. Embryogenic callus was recorded as compact, globular and light yellowish in color. The embryogenic callus morphology was further confirmed with scanning electron microscopy (SEM) analysis. For regeneration, induced calli were treated with various concentrations of Kin (0.5-1.5 mg L(-1)), BAP, NAA and 0.5 mg L(-1) of TDZ. The result showed that the maximum regeneration frequency (100%) was achieved on MS medium containing BAP (0.5 mg L(-1)), Kin (1.5 mg L(-1)), NAA (0.5 mg L(-1)) and TDZ (0.5 mg L(-1)) within four weeks. Developed shoots were successfully rooted on half strength MS free hormone medium and later transferred into a pot containing soil for acclimatization. This cutting-edge finding is unique over the other existing publishable data due to the good regeneration response by producing a large number of shoots.

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Aims: To investigate the influence of carbon sources and additives/surfactants on the mycelium growth and exopolysaccharides (EPS) production, including the morphology during submerged cultivation of Pleurotus ostreatus in the minimal-medium as the base medium. Methodology and results: Pleurotus ostreatus was cultivated in different types of carbon sources to investigate the effects of carbon sources to mycelium growth and changes of mycelium morphology which directly affects the synthesis of EPS. In addition, additives or surfactants can increase the bioavailability of less soluble substrates in the cultured medium for the mycelium growth and indirectly affects the EPS production. In this study, the cultivation of P. ostreatus in the minimal-medium by using glucose as the carbon source with the addition of lecithin at 1% (w/v) gave the highest EPS production 4.53 ± 0.30 g/L, an increase of about 89.53% when compared to the cultivation without the addition of lecithin. Addition of lecithin changes morphology of the pellets outer layer and under microscope showing a dense hyphal network surrounding the pellets with the sizes of micro pellets almost 0.5-1.5 mm which contributed to the increase of EPS production after 14 days cultivation at 26 °C. Conclusion, significance and impact of study: The choice of the carbon source should not only be for high productivity rate of mycelium growth and EPS production, but a cheaper alternative source should also be considered. In conclusion, high mycelium biomass and EPS production was achieved either by changes of the morphology through the type of carbon source and addition of additives such as lecithin.

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