Judul: In vitro regeneration of terubuk (Saccharum edule)
Abstrak: Terubuk is one of the potential vegetable known as cauliflower sugarcane. It is characterized by unusual, swollen and aborted inflorescences, which is sweet and edible. The inflorescences are used as a source of food in Fiji, New Guinea, Indonesia and Malaysia by the indigenous people. The inflorescences are abnormal in the sense that they remain enclosed within the leaf-sheaths, forming a compact mass about the size of a banana fruit. Terubuk is produced and consumed locally and traded in local market only. In Indonesian’s traditional market, it is sold in bunches of 10. Terubuk is closely related to Saccharum officinarum, S. spontaneum, and S. robustum. It is exclusively propagated by cuttings or by division of clumps. To provide more inflorescences, it needs higher plants production. Its production needs cutting materials or propagules. Conventional propagation requires a lot of planting material. Tissue culture is an alternative propagation technique to solve the inavailability of plant material. The objective of this research was to obtain the best method to propagate terubuk using in vitro micropropagation through direct and indirect organogenesis. Flower stalks were used as explants. The explant’s sterilization was done by spraying the inflorescences with alcohol 96 %, then the flower was burnt. The indirect organogenesis using calli induction showed that the best medium was MS + 3.0 mg l-1 2,4-D + 1.0 mg l-1 kinetin. This media did not produce shoots from calli proliferation stage. It was only able to produce roots. The other method was by direct organogenesis. It was shown that the best medium was MS + 0.25 mg l-1 thidiazuron + 0.1 mg l-1 NAA + 0.25 mg l-1 GA3 to produce shoots in 2 weeks without putting the explants in calli induction medium. Shoots obtained through the media varied in size. Only shoot with 1-3 cm in size were rooted. Root formation required full strength of MS salt. The percentage of success in rooting ranged from 50-80%. Acclimatization has been done, however, after 2 weeks the planlet did not survive.
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Judul: In Vitro Micropropagation and Induction of Alkaloid Accumulation in Jeruju (Hydrolea spinosa L.).
Abstrak: Hydrolea spinosa is one of the potential plant for antimalarial drugs. Alkaloid compound in this plant has antiplasmodial activity. Conventional vegetative propagation through auxilarry branching was inhibited cause required its habitation, i.e. wetland. Tissue culture as an alternative propagation technique of this plant was required a protocol of its micropropagation. This method was also used in the effort of the improvement of alkaloid content through various of manipulation methods. The objectives of these research were to find out the effect of plant regulators and explants types on shoot induction, proliferation and elongation, calli induction of H. spinosa tissue culture, and to improved alkaloid content with several methods in vitro. Shoot induction and proliferation was studied using shoot tip and node segments within various concentration of BAP, whereas calli induction from young leaf and stem explants used various concentration of auxins (2.4-D and NAA) with high level of cytokinin (BAP). Shoot elongation was carried using different strength of MS salts (full-, a half-, one-quarter strength) and with or without addition of gibberellin (GA3). Precursor amino acids (tryptophan), elicitor (salicylic acids) and high sucrose feeding (6%) used to improve alkaloid content in calli and shoot cultures. Cytokinin level produced a significant response on the numbers of shoot formed per explants and also showed effect on node number. Both of shoot tip and node segments had an equal potential as explants in shoot induction and proliferation. The presence of plant growth regulator was important to induce calli but the level was no significant effect on calli initiation. The young leaf explants was rather than stem in calli induction. The half strength of MS salts produced rooting of the shoot with vigorous performance. Planlets produced from elongation phase were acclimatized and had viability as 75%. All of the treatments were not improve the alkaloid content qualitatively.
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Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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