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: Application of Plasma Fine Bubble for Breaking of Dormancy and Promoting of Germination for Shallot Bulbs
Abstrak: Bawang merah (Allium ascalonicum L.) merupakan salah satu komoditas unggulan di Indonesia. Bawang merah umumnya digunakan untuk bumbu masakan dan obat tradisional. Populasi yang semakin meningkat menyebabkan peningkatan konsumsi bawang merah di Indonesia, tetapi produksi bawang merah di Indonesia masih relatif rendah. Teknologi untuk mempersingkat masa dormansi umbi bawang merah harus diterapkan untuk mendorong perkecambahan benih umbi bawang merah sehingga umbi bawang merah yang baru dipanen dapat lebih cepat digunakan sebagai bahan tanam. Penggunaan teknologi Plasma Fine Bubble (PFB) diharapkan mampu mempercepat laju perkecambahan benih umbi bawang merah. Tujuan penelitian ini adalah untuk menguji efektivitas PFB untuk pematahan dormansi dan peningkatan perkecambahan pada benih umbi bawang merah. Bawang merah lokal diberi perlakuan perendaman setelah 1 minggu setelah panen. Perlakuan perendaman menggunakan aquades, PFB 1 ppm, PFB 2 ppm dengan waktu perendaman selama 30 menit dan 1 jam serta perlakuan tanpa perendaman sebagai kontrol. Perendaman dilakukan setiap minggu sekali selama 3 minggu lalu dilakukan pengamatan titik tumbuh untuk mengetahui apakah bawang merah sudah selesai dormansi. Bawang merah yang sudah selesai dormansi dilakukan uji perkecambahan dengan cara menanam bawang merah pada polybag dan diamati selama hingga 7 minggu setelah tanam (MST). Parameter yang diamati selama penelitian berupa rasio titik tumbuh, daya kecambah, persentase kerusakan, serta tinggi tanaman. Hasil penelitian menunjukkan bahwa perendaman UFB 1 ppm dan 2 ppm dapat mempercepat pematahan dormansi yang ditandai dengan nilai rasio titik tumbuh yang tinggi, meningkatkan laju perkecambahan, serta meningkatkan pertumbuhan tanaman yang ditandai dengan ukuran tanaman bawang merah yang lebih tinggi. Hasil tersebut memberikan perbedaan dan pengaruh nyata terhadap daya berkecambah dan tinggi tanaman tetapi tidak memberikan pengaruh nyata terhadap rasio titik tumbuh., Shallot (Allium ascalonicum L.) is one of the leading commodities in Indonesia. Shallot is often used for seasoning and traditional medicine. The increasing population causes an increase in shallot consumption in Indonesia, but shallot production in Indonesia is still relatively low. Indonesian farmers often use bulbs in shallot cultivation. Technology to shorten the dormancy period and of shallot bulbs must be applied to promote shallot bulbs germination so that newly harvested shallot bulbs can be used as planting material sooner. The use of Plasma Fine Bubble (PFB) technology is expected to accelerate the germination rate of shallot bulbs. The objective of this research is to test the effectiveness of PFB for breaking of dormancy and promoting of germination rate for shallot bulbs. Local shallots were given immersion treatment after 1 week harvest. The immersion treatment using distilled water, PFB 1 ppm, PFB 2 ppm for 30 minutes and 1 hour while treatment without immersion is being used as control. The treatment was carried out once every week for 3 weeks then the growing point is observed to analyze whether the shallots had broken the dormancy. Shallots that have broken dormancy are subjected to a germination test by planting them in polybags and observed for up to 7 weeks after planting. Parameters observed during the study were the ratio of growing point, germination rate, damage percentage, and plant height. The results showed that 1 ppm and 2 ppm UFB immersion accelerated the breaking of dormancy
Keyword: Plasma Fine Bubble, dormansi, laju perkecambahan, bawang merah

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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