Judul: Induced mutation by gamma-ray irradiation for the development of superior orchid clones Spathoglottis plicata Blume. Accession Bengkulu
Abstrak: Spathoglottis plicata Blume. is one species of orchids with lower level of genetic diversity, especially in flower color compared to other orchids. S. plicata accession Bengkulu usually produce pink to purple flower with a bright purple stems and flower stalk. The aimed of the research were (1) to find the tissue culture protocols to propagate S. plicata though protocorm like bodies, (2) to induce the genetic diversity of S. plicata accession Bengkulu using gamma irradiation to plantlets, (3) to determine a lethal dose 50% (LD50) for plantlets through gamma irradiation, and (4) to identify genetic variations of orchids S. plicata and its mutants using morphological characters and ISSR markers. The growth and multiplication of protocorm like bodies can be induced by using MS medium supplemented with 50 to 100 ml L-1 coconut water. The best treatment to develope plb into plantlet was MS medium containing of vitamin B5 with addition of 75 ml L-1 coconut water and 2% activated charcoal or MS medium supplemented with 20 μM BA and 2% activated charcoal. Furthermore, MS medium containing of B5 vitamin enriched with 20 μM BA or MS medium containing of vitamin B5 with addition of 75 ml L-1 coconut water was the best treatment for plantlet multiplication. Induced mutation using gamma-ray irradiation to the plbs and plantlets could increase the genetic diversity of S. plicata. Lethal Dose 50% (LD50) of plb survival rate was 47.71 Gy, while LD50 of plantlet survival rate was 50.74 Gy. Gamma-ray irradiation to the plantlet resulted nine potential mutants (0.36%) that be selected by morphological characters of the shape and color of flowers. Morphological characters and ISSR markers can be used to identify the mutants. Clustering analysis by using Unweighted Pair Group Method and Arithmatic Average and Principal Component Analysis of 12 samples and its mutants based on ISSR markers could clearly distinguish the wild type and its mutants. It formed five groups of coefficient similarity at 0.68 with goodness of fit correlation matrix value of 0.91 (very suitable). The grouping of those samples was more accurate and more efficient by using ISSR markers compared to the morphologycal markers. This clustering successfuly separated the wild type and its mutants.
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Judul: Protocorm-like Bodies (plbs) induction and molecular characterization F2 population of phalaenopsis orchids
Abstrak: Efforts to increase the availability of Phalaenopsis orchid propagation material to provide quality propagules can be done either vegetatively or generatively. Tissue culture methods could be used as an alternative for vegetative plant propagation to produce uniform seedlings in large quantities. The success of this method is determined by some factors such as plant genotype, age and type of explants and culture media. The genotypes of plants from crossing of superior hybrid could be used for selection of new variety or as material for plant breeding. Molecular markers is an approach that can be used for plant selection at early growth so that it can be seen plants which have the same genotype or similar each other. The research objectives were to get the optimal medium for induction of plbs from leaf explants of Phalaenopsis orchids to make F2 population liniclone and molecular characterization of the Phalaenopsis orchid F2 population using SSR markers. This research consist of 4 phases: (1) plbs medium induction test on F2 populations of Phalaenopsis orchid 2) liniclone formation the F2 population using the best medium of phase 1; 3) Induction of axillary shoots; (4) Isolation of DNA individuals in F2 population and molecular characterization by SSR markers. The results of the phase 1 was an appropriate medium for plbs induction namely the medium ½MS (Murashige and Skoog) with addition of BAP 0.5 mg L-1 + TDZ 0.5 mg L-1 + 2.4-D 0.2 mg L-1. Explants forming plbs response in the medium was 80%. On the phase 2, twenty-six accessions produce plbs between 4-55 in 12 weeks after planting. Most plbs formation obtained on the accession 9 (55 plbs) and highest weight on accession plbs 3 (17.45 g). On the phase 3, all accessions did not produce axillary shoots until 12 weeks after planting. On the phase 4, in experiments of the molecular characterization of F2 population, three primary showed polymorphism banding pattern namely IPS14, PeGBMS466 and PeGBMS478 primary. The average PIC value obtained was 0.290 with the highest PIC value was 0.38 on PeGBMS478 locus. The average heterozygosity (He) 0.367 and average homozygosity (Ho) 0.491 with the He highest score at the locus PeGBMS478 was 0.496. Level of genetic similarity between P1 to P2 by 48%, while the genetic similarity between P2, F1, F2 and 21 progeny was approximately 90%.
Keyword: Genetic similarity, medium composition, liniclone, SSR, axillary shoot

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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