Judul: Effect of BAP and GA3 on Flowering and Bulb Production of Polianthes tuberosa L. var. Roro Anteng
Abstrak: Kebutuhan bunga potong sedap malam (Polianthes tuberosa L.) terus meningkat setiap tahun. Budi daya tanaman sedap malam dilakukan menggunakan umbi karena sulit untuk menghasilkan benih dan penggunaan benih masih terbatas hanya untuk pemuliaan tanaman. Produksi umbi tidak mencukupi kebutuhan bahan tanam untuk memproduksi bunga potong sesuai permintaan. Penelitian ini bertujuan meningkatkan produksi dan mutu umbi sedap malam varietas Roro Anteng melalui perendaman umbi dalam BAP dan GA3 sebelum tanam. Penelitian dilakukan dalam rumah plastik di Kebun Percobaan Tajur, IPB University. Percobaan dilaksanakan dalam RKLT satu faktor yaitu perendaman umbi dalam BAP pada konsentrasi 50, 100 150, dan 200 ppm dan GA3 pada konsentrasi 100, 200, 300, dan 400 ppm selama 24 jam. Umbi sedap malam varietas Roro Anteng yang sesuai untuk dataran rendah digunakan dalam penelitian ini. Hasil pengamatan menunjukkan bahwa perendaman umbi bibit sedap malam varietas Roro Anteng dalam BAP (100‒200 ppm) atau GA3 (200‒400 ppm) selama 24 jam meningkatkan produksi umbi utama 64‒71% pada 7 BST, dengan diameter umbi berkisar antara 2,08‒2,29 cm. Penggunaan BAP atau GA3 tidak dapat meningkatkan produksi umbi anakan. Perendaman umbi bibit dalam BAP atau GA3 juga mempercepat pembungaan, dengan persentase tanaman berbunga 20,0‒46,7% (< 7 BST). Bunga yang terbentuk tidak memenuhi standar bunga potong sedap malam di Indonesia.
Keyword: floret, jumlah kuntum, mutu bunga, perendaman umbi

Judul: Induksi Pertunasan pada Umbi Tanaman Sedap Malam (Polianthes tuberosa L.) dengan Pengasapan dan Aplikasi Zat Pengatur Tumbuh
Abstrak: Increasing flower production of Polianthes is hindered by limited supply of bulb. Newly harvested bulb shows after ripening phenomenon, in which new bulbs are not readily sprouting. Farmers usually air or sun-dried the bulbs followed by curing above the kitchen stove for 1-3 months to induce sprouting. It is therefore necessary to accelerate sprouting. The purpose of this research was to study if bulbs of different sizes will sprout at the same time and if sprouting could be accelerated. The research was conducted at the Laboratory of Seed Science and Technology, Department of Agronomy and Horticulture, IPB Darmaga during November 2010 - February 2011. The research consisted of two experiments. In the first experiment bulbs were grouped into small (0.5 < Ø < 1.5 cm), medium (1.5 < Ø < 2.5 cm) and large ( Ø > 2.5 cm) sizes and subjected to air-drying or curing for six days. Each treatment was replicated four times with 20 bulbs for each experimental unit. In the second experiment sprouting was induced using BAP, GA3 or cured as three different set of experiments. The concentrations of BAP were 0, 100, 200, 300 ppm, whereas GA3 were 0, 50, 100, 150, and 200 ppm. Curing was carried out for 0, 2, 4, 6 days. The result showed that larger bulb produced higher number of sidebulb, so did curing as opposed to air-drying. The large bulb produced higher percentage of sprouting bulb than medium and small bulb. The larger the bulb the earlier they sprout. Result from the second experiment showed that the higher concentration of BAP give higher number of sidebulbs and earlier sprouting. Bulbs treated with BAP at 300 ppm uniformly sprouted within one week after treatment. However, it was not significantly different from BAP at 200 ppm. Use of GA3 up 100 ppm affected number of sidebulb and shoot length but did not affect percentage of sprouting bulbs. Use of curing did not affect number of sidebulb, shoot length as well as percentage of sprouting bulbs.
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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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