Judul: Optimization of Basic Media and Growth Regulator for In Vitro Multiplication of Jeruk Kunci (Citrus x microcarpa Bunge) Plant
Abstrak: Jeruk kunci (Citrus x microcarpa) merupakan tanaman jeruk dengan habitus semak yang banyak tumbuh di wilayah Bangka-Belitung. Jeruk ini memiliki banyak manfaat baik secara langsung atau tidak langsung. Akan tetapi, pertumbuhan dan perkembangbiakannya lambat, sehingga salah satu upaya memperbanyak tanaman tersebut ialah dengan kultur in vitro. Penelitian ini bertujuan menentukan kombinasi antara media dasar MS atau DKW dengan BAP yang optimal untuk multiplikasi tunas jeruk kunci secara in vitro. Penelitian ini menggunakan RAL dengan dua faktor, yakni jenis media dan taraf konsentrasi BAP. Pemberian BAP pada 0,1-2,0 mg/L ke dalam media MS atau DKW mampu menginduksi kalus dan tunas adventif dibandingkan tanpa BAP. Perlakuan DK3 dan DK4 menunjukkan waktu muncul kalus tercepat pada minggu kedua, sedangkan waktu muncul tunas adventif secara berurutan juga paling cepat pada minggu ketiga dan kelima. Rata-rata jumlah tunas adventif (7,2 tunas), tinggi tunas (2,14 cm), jumlah tunas aksilar (19,6 tunas), dan jumlah daun (50,4 helai) tertinggi ditunjukkan oleh perlakuan DK3., Citrus x microcarpa, given in Indonesia as jeruk kunci, is a citrus plant with a shrub habitus that grows in the majority in the Bangka-Belitung Islands, offering numerous direct and indirect benefits. However, its growth and reproduction are slow, so one of the efforts to reproduce the plants is by in vitro culture. This study aimed to determine an optimal combination of MS or DKW basic media with benzyl amino purine (BAP) growth regulator to get multiple shoots in vitro. This study was designed in CRD with two factors: the basic media type and BAP concentration levels. The provision of BAP at 0,1-2,0 mg/L added to MS or DKW media induced callus and adventitious buds compared to the control without BAP. The DK3 and DK4 treatments showed the fastest callus emerging time, which was in the second week, while adventitious buds were also obtained the most rapid in both media, the third and fifth weeks, respectively. The highest average number of adventitious buds (7,2 buds), shoot height (2,14 cm), number of axillary buds (19,6 buds), and number of leaves (50,4 leaves) were shown by treatment DK3.
Keyword: adventitious bud, axillary bud, BAP concentration, basic medium

Judul: Propagasi mikro dan Sambung Mikro Jeruk Keprok Garut (Citrus reticulata) Hasil Mutagenesis In Vitro dengan Batang Bawah Japansche Citroen
Abstrak: This study aimed to get proper concentration of kinetin for multiplication of Mandarin var. Garut as derived from in vitro mutation, to determine period of immersion of Japansche citroen seed in GA3 10 mg/l solution and to get proper concentration of sucrose concentration in agar for grafted plant. This research is consist of three steps. For the first step, shoot as derived from in vitro mutation multiplicated with 2 books cutting and planted in standard medium with kinetin 1 mg/L, 3 mg/L, 5 mg/L added. For the second step, JC seed immersed in 10 mg/L of GA3 for 1, 2, and 3 hours and planted in standard medium. For the last step, explant from the first and second step was grafted and planted in standard medium with sucrose 30 g/L, 50 g/L, and 70 g/L. The optimal concentration of kinetin for scion growth is 1 mg/l and for multiplication is 5 mg/l. The best period for rootstock immersion in GA3 solution is 3 hours. The best percentage of success micrografting occured in 70 g/l sucrose medium.
Keyword: Bogor Agricultural University (IPB), sucrose, multiplication, kinetin, gibberellin

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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