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: Effect of Plant Growth Regulator and Explant Size on In Vitro Turmeric Plants (Curcuma domestica Val.)
Abstrak: Kunyit merupakan salah satu tanaman biofarmaka dengan kegunaan dan jumlah permintaan yang banyak di Indonesia. Peningkatan produksi rimpang kunyit melalui kultur jaringan memiliki beberapa keunggulan seperti potensi mendapat bibit yang sehat, hasil dalam jumlah yang banyak serta berkesinambungan. Penelitian ini bertujuan untuk mendapatkan konsentrasi zat pengatur tumbuh (ZPT) kinetin dan ukuran eksplan terbaik pada pembiakan in vitro tanaman kunyit. Penelitian dilaksanakan pada bulan Januari 2022 hingga April 2023 di Laboratorium Biologi Molekuler Tanaman 1, Departemen Agronomi dan Hortikultura, Fakultas Pertanian, IPB University, Dramaga, Bogor. Penelitian menggunakan rancangan acak lengkap faktorial. Faktor pertama adalah konsentrasi ZPT kinetin (0,5 ppm, 1 ppm, 1,5 ppm) + NAA 0,1 ppm dan faktor kedua adalah ukuran eksplan (besar dan kecil). Didapat 6 taraf perlakuan yang diulang sebanyak 4 ulangan, dengan tiap satuan percobaan terdapat 3 eksplan yang ditanam masing-masing dalam 1 botol, sehingga didapat total 72 satuan pengamatan. Hasil penelitian menunjukkan ukuran eksplan berpengaruh sangat nyata terhadap panjang akar terpanjang dan keberhasilan aklimatisasi, serta interaksi konsentrasi ZPT dan ukuran eksplan berpengaruh nyata terhadap hari muncul akar., Turmeric is a biopharmaceutical plant with many uses and demand in Indonesia. Increasing the production of turmeric rhizomes through tissue culture has several advantages, such as the potential to obtain healthy seeds, produce large quantities, and be sustainable. This research aims to obtain the best concentration of the plant growth regulator (PGR) kinetin and the explant size for in vitro breeding of turmeric plants. The research was conducted from January 2022 to April 2023 at the Plant Molecular Biology Laboratory 1, Agronomy and Horticulture Department, Agriculture Faculty, IPB University, Dramaga, Bogor. The research used a completely randomized factorial design. The first factor is the concentration of kinetin PGR (0.5 ppm, 1 ppm, 1.5 ppm) + NAA 0.1 ppm; the second factor is the explant size (large and small). There were 6 treatment levels, which were repeated in 4 repetitions, with each experimental unit having 3 explants planted in 1 bottle each, so a total of 72 observation units were obtained. The results showed that explant size had a very significant effect on the longest root length and acclimatization success, and the interaction of PGR concentration and explant size had a significant effect on the days of root emergence.
Keyword: Akar, Kinetin, Kultur jaringan, Root, Tissue culture

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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