Judul: Induction of Poliploid Diversity and  Regeneration Capability of Coelogyne fragrans Schltr. with Colchicine
Abstrak: Coelogyne fragrans merupakan anggrek yang berpotensi dikembangkan sebagai tanaman hias pot. Pemuliaan mutasi menggunakan kolkisin dapat meningkatkan keragaman genetik dan menginduksi poliploidi sehingga berpotensi meningkatkan kualitas karakteristik sifat agronomi tanaman. Penelitian ini bertujuan mempelajari respon C. fragrans terhadap konsentrasi kolkisin dan durasi perendamannya. Penelitian dilaksanakan dari bulan Mei hingga Agustus 2019 di Laboratorium Kultur Jaringan Tanaman II, Departemen Agronomi dan Hortikultura, Fakultas Pertanian, Institut Pertanian Bogor. Rancangan yang digunakan dalam penelitian ini adalah Rancangan Acak Lengkap (RAL) Faktorial dengan dua faktor, konsentrasi kolkisin yang terdiri dari 6 taraf: 0.0%, 0.02%, 0.04%, 0.06%, 0.08%, dan 0.10% dan durasi perendaman yang terdiri dari 2 taraf: 24 dan 48 jam. Pengamatan dan pengukuran dilakukan setiap minggu selama 12 minggu sejak eksplan ditanam pada media dasar ½ MS. Parameter yang diamati meliputi tingkat persentase hidup, persentase eksplan berploriferasi, jumlah tunas terbentuk dan jumlah akar terbentuk. Durasi dan konsentrasi kolkisin yang digunakan dalam penelitian ini berada dalam kisaran aman untuk persentase hidup eksplan. Perendaman 24 jam menghasilkan jumlah eksplan berproliferasi nyata lebih banyak dibandingkan perendaman 48 jam. Peningkatan konsentrasi kolkisin dari 0.02% hingga 0.10% tidak mempengaruhi persentase hidup eksplan dan jumlah tunas pada 12 minggu setelah kultur., Coelogyne fragrans is one of the orchid species that has the potential to be developed as potted flowering ornamentals. Mutation breeding using colchicine enhance the genetic diversity and to induce polyploidy, thus can potentially improve plant growth and flowering characteristics.The study was conducted to determine the responses of C. fragrans to different concentrations of colchicine and duration of immersion. The research was carried out from May to August 2019 at the Plant Tissue Culture Laboratory II, Department of Agronomy and Horticulture, Faculty of Agriculture, Bogor Agricultural University. The design used in this study was a completely randomized design (CRD) with two factors, concentration of colchicine which consisted of 6 levels: 0.0%, 0.02%, 0.04%, 0.06%, 0.08%, and 0.10%, and duration of immersion which consists of 2 levels: 24 and 48 hours. Observations and measurements were conducted every week for 12 weeks since the explants were planted on MS base media. Parameters measured included survival percentage, percentage of p explant, number of formed shoots and number of formed roots. The duration and concentration of colchicine used in this study were within the safe range for the explant survival percentage. Immersion in colchicine for 24-hour resulted in significantly more number of explant proliferated than 48-hour immersion. Increasing the concentration of colchicine from 0.02% to 0.10% did not affect the percentage of explant survival and the number of shoots at 12 weeks after culture.
Keyword: kolkisin, mutasi, orchidaceae, proliferasi, tunas, colchicine, mutation, proliferation, shoots, Coelogyne fragrans

Judul: Induction of Polyploidy Grammatophyllum speciosum Mutation with Colchicine on In Vitro at Different Consentrations and Duration of Immersion
Abstrak: Anggrek Grammatophyllum speciosum merupakan spesies anggrek yang banyak digunakan sebagai tanaman hias dan bisa digunakan sebagai obat. Keragaman genetik diharapkan mampu ditingkatkan dengan penggunaan kolkisin untuk tujuan perakitan varietas baru yang lebih unggul. Penelitian ini bertujuan mempelajari pengaruh interaksi konsentrasi dengan lama perendaman kolkisin pada tingkat ploidi anggrek Grammatophyllum speciosum berdasarkan pengamatan morfologi dan histologi. Induksi mutasi dengan kolkisin dilakukan menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) 2 faktor, yaitu konsentrasi kolkisin dan lama perendaman. Hasil penelitian menunjukkan 0,01% dan 0,02% kolkisin selama 2 jam menghasilkan pertumbuhan protocorm sekunder dan tunas terbaik. Interaksi konsentrasi kolkisin dan lama perendaman berpengaruh terhadap jumlah kloroplas, kerapatan stomata, dan ukuran stomata. Konsentrasi kolkisin dan lama perendaman meningkatkan jumlah kloroplas dan ukuran stomata, serta menurunkan kerapatan stomata. Jumlah kloroplas terbanyak diperoleh dari perlakuan kolkisin 0,04% selama 48 jam. Kerapatan stomata terendah dihasilkan dari perlakuan kosentrasi kolkisin 0,04% selama 24 jam. Ukuran stomata terbesar dihasilkan dari perlakuan kolkisin 0,06% selama 2 jam (panjang stomata) dan 0,06% selama 48 jam (lebar stomata)., Grammatophyllum speciosum orchid is an orchid species which is widely used as an ornamental plant and also medicine. Genetic diversity is expected to be increased by using colchicine to create new, superior varieties. The objective of this research is examine the effect of concentration and duration of immersion colchicine on the ploidy level of Grammatophyllum speciosum orchids based on morphological and histological observations. Mutation induction with colchicine was carried out using a Randomized Complete Block Design (RCBD) with 2 factors; colchicine concentration and duration of immersion. The results showed that 0.01% and 0.02% colchicine for 2 hours is the optimum treatment for secondary protocorm and shoot growth. The interaction of colchicine concentration and duration of immersion were affected to the numbers of stomatal chloroplasts, size and stomatal density. Colchicine consentration and duration of immersion increased the number of stomatal chloroplasts and size, also decreased stomatal density. The highest number of chloroplasts was obtained from 0.04% colchicine treatment for 48 hours immersion, followed by the lowest stomata density which in 0.04% colchicine concentration for 42 hours immersion. The largest stomatal size was obtained from 0.06% colchicine treatment for 2 hours (stomatal length) and 0.06% for 48 hours (stomatal width).
Keyword: colchicine, concentration, duration of soaking, Grammatophyllum speciosum, mutation

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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