Judul: Pengaruh Ukuran Eksplan terhadap Keberhasilan Inisiasi Kultur Jaringan Eboni (Diospyros celebica Bakh.)
Abstrak: Eboni termasuk slow growing species dan memiliki benih rekalsitran. Pengembangbiakan eboni dapat dilakukan dengan kultur jaringan. Tujuan penelitian ini adalah menganalisis pengaruh ukuran eksplan terhadap faktor keberhasilan inisiasi eboni. Eksplan yang digunakan diambil dari tunas aksilar dan tunas apikal dengan ukuran 1,1–1,5 cm, 0,6–1,0 cm, 0,1–0,5 cm dan 0,05–0,09 cm. Eksplan kemudian diinisiasi untuk mendapatkan kultur eboni steril. Hasil penelitian menunjukkan bahwa ukuran eksplan berpengaruh terhadap keberhasilan inisiasi eboni. Semua ukuran eksplan yang digunakan dapat menghasilkan kultur eboni steril sebesar 55–85%. Semakin kecil ukuran eksplan eboni, maka semakin tinggi tingkat kematian kultur. Ukuran eksplan eboni terbesar (1,1–1,5 cm) memiliki tingkat browning yang tertinggi dibandingkan dengan ukuran eksplan lainnya. Secara umum, ukuran eksplan eboni berpengaruh terhadap faktor keberhasilan inisiasi eboni, tingkat kematian kultur, dan tingkat browning., Ebony is a slow growing species and has recalcitrant seeds. Ebony propagation can be done by tissue culture. The purpose of this study was to analyze the effect of explant size on the success factor of ebony initiation. The explants used were taken from axillary and apical buds with sizes of 1.1–1.5 cm, 0.6–1.0 cm, 0.1– 0.5 cm and 0.05–0.09 cm. The explants were then initiated to obtain sterile ebony cultures. The results showed that the size of the explant had an effect on the success of ebony initiation. All sizes of explants used can produce sterile ebony cultures of 55–85%. The smaller the size of the ebony explants, the higher the mortality rate of the culture. The largest size of ebony explants (1.1–1.5 cm) had the highest level of browning compared to other explant sizes. In general, the size of the ebony explants influenced the success of ebony initiation, the culture mortality rate, and the browning rate.
Keyword: eboni (Diospyros celebica), initiation, sterilization, explant size

Judul: Combination of Planting Media and Explant Treatment in In Vitro Tissue Culture of Aren (Arenga pinnata (Wurmb) Merr.) Seeds
Abstrak: Kultur jaringan dapat digunakan sebagai teknik budidaya tanaman dengan waktu dormansi lama, seperti aren. Namun pertumbuhan eksplan kultur jaringan juga dipengaruhi oleh berbagai faktor, salah satunya kontaminasi. Penelitian ini bertujuan mengidentifikasi dan mendeskripsikan keberhasilan serta pertumbuhan eksplan pada kultur jaringan aren (Arenga pinnata). Biji aren disterilisasi di luar Laminar Air Flow dan di dalam Laminar Air Flow lalu dibagi ke dalam 12 kombinasi perlakuan media dan eksplan. Hasil penelitian menunjukkan kontaminasi eksplan dominan disebabkan oleh cendawan eksternal pada kulit biji eksplan. Browning terjadi pada eksplan embrio di dalam media MS, BAP2, glisin, pepton, dan myo-inositol yang mengalami proses pertumbuhan kalus. Eksplan steril hingga akhir pengamatan merupakan eksplan embrio pada ketiga jenis media tanam yang digunakan. Pertumbuhan eksplan tertinggi pada media MS 0 dan media kombinasi MS, BAP 2, Myo-inositol, Glisin, dan Pepton dengan jenis ekplan biji dikupas lalu direndam larutan giberelin., Tissue culture is a technique that can be used to cultivate plants that have a long dormant period, such as the sugar palm. However, contamination is one element that affects the growth of tissue culture explants. The purpose of this research is to determine and report the success and growth of sugar palm explants in tissue culture (Arenga pinnata). palm seeds were sterilized outside the laminar air flow and inside the laminar air flow then separated into 12 different medium and explant treatment combinations. The results showed that the dominant explant contamination was caused by external fungi on the explant seed coat. Browning was observed in embryo explants grown on MS, BAP2, glycine, peptone, and myo-inositol medium during the callus formation process. Sterile explants until the end of the observation were embryo explants on the three types of growing media used. Explants grew the fastest on MS 0 media and a mixture of MS, BAP 2, Myo-inositol, Glycine, and Peptone media with peeled seed explants immersed in gibberellin solution.
Keyword: aren, kontaminasi, sterilisasi, sugar palm, contamination, sterilization

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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