Judul: Chromosome Doubling of White Albizia (Albizia falcataria L. Fosberg) Seeds through Oryzalin Treatment and Identification of Tetraploid Plants
Abstrak: Sengon (Albizia falcataria L. Fosberg) adalah salah satu tanaman kehutanan yang memiliki nilai ekonomi tinggi. Penggandaan kromosom sengon diharapkan akan menghasilkan tanaman sengon yang lebih baik secara morfologi atau kualitas kayunya. Penelitian ini bertujuan untuk mengetahui konsentrasi oryzalin dan periode perlakuan yang efektif dalam menggandakan kromosom sengon melalui perlakuan benih. Selain itu penelitian ini bertujuan mengamati pengaruh perendaman benih sengon dalam oryzalin terhadap pertumbuhan kecambah dan perubahan secara sitologi dan anatomi yang ditimbulkannya, serta untuk identifikasi tanaman sengon tetraploid. Konsentrasi oryzalin 5 μM dengan periode perendaman 6 jam merupakan perlakuan paling efektif dalam menginduksi penggandaan kromosom benih sengon yang menghasilkan 60% tanaman sengon tetraploid dengan tingkat kematian paling rendah dari perlakuan lain yaitu 50%. Pendugaan perubahan tingkat ploidi dari diploid menjadi tetraploid menyebabkan jumlah kloroplas pada sel penjaga stoma semakin tinggi dari rataan 6,5 kloropas per stoma menjadi 12,9 kloroplas per stoma, kerapatan stomata semakin rendah dari rataan 610,0 stomata per mm2 menjadi 342,1 stomata per mm2, dan ditandai dengan penghambatan pertumbuhan tinggi kecambah dari rataan 77,1 cm menjadi 60,6 cm. Peningkatan jumlah kloroplas menjadi sekitar dua kali lipat dapat dijadikan alat penduga efektif dalam peningkatan tingkat ploidi dari diploid menjadi tetraploid pada sengon.
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Judul: Penggandaan Kromosom Jati (Tectona grandis L.) dengan Oryzalin dalam Kultur In Vitro dan Pendugaan Tingkat Ploidi
Abstrak: Teak (Tectona grandis L.) is one of the forestry plants that have a high economic value and an important role in carbon absorbing. Chromosome doubling in teak was intended to produce a better plant both morphologically and it’s wood quality. Antimicrotubule, such as oryzalin treatment is one of the chromosome doubling inducing method. This research was conducted to get the most effective concentration and treatment period to induce the chromosome doubling of teak through in vitro culture. It’s effectivity was measured by the changes of chloroplast number in the stomatal guard cell and stomatal density, also supported by the lowest lethal effect that was measured by it’s survival percentation. The most effective oryzalin treatment to induce chromosome doubling of teak from diploids into tetraploids was estimated at 5 μM concentration with 3 days treatment period. The survival at this treatment reached 70% of the treated plants. In which about 60% of the treated plants had a doubled chloroplast number in their guard cells from average 6,0-11,9 into 12,0-23,9 chloroplast per stoma along with the decreased of stomatal density.
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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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