Judul: Induksi Keragaman Genetik dengan Mutagen Sinar Gamma pada Nenas Secara In Vitro
Abstrak: Improvement of the genetic variability of pineapple plant can be done by mutation induction with gamma rays. The aim of the research was to increase genetic variability on pineapple through gamma irradiation of calli that have been frequently subculture. Medium for calli induction was MS + 1 mg L-1 benzylaminopurine (BAP) + 0.05 mg L-1 2,4-dichlorophenoxyacetic acid (2,4-D), while the medium for shoot regeneration was MS + 1.5 mg L-1 kinetin + 0.5 mg L-1 NAA. Calli were then irradiated with 0, 15, 25 and 35 Gy gamma irradiation. Completely randomized design with 40 replication were used in this experiment. The result showed that irradiation gamma rays were affected on growth and regeneration on calli. Generally, the 15 Gy induced variance of shoot growth, phenotypic and genetic variability. Gamma irradiation changed the banding pattern of DNAs as they were amplified with five primers of ISSR molecular marker to analysis genetic variability among regenerant. Serial selection based on erect leaves structures and narrow canopy diameter character resulted to seven regenerants mutant with erect leaves structure and narrow canopy diameter without reducing plant height and leaves number compared to those of control regenerants population.
Keyword: 

Judul: Induksi Keragaman Genetik Dengan Mutagen Sinar Gamma pada Nenas Secara In Vitro
Abstrak: Nenas (Ananas comosus (L.) Merr) merupakan tanaman buah yang potensial untuk dikembangkan karena telah banyak digunakan baik sebagai makanan segar, bahan industri makanan, kosmetik, obat-obatan dan industri tekstil. Produktivitas nenas di Indonesia masih rendah dan rasio bobot buah dengan tanaman hanya berkisar 0.43-0.46, sedangkan di negara maju telah mencapai rasio 0.6. Pusat Kajian Buah Tropika IPB telah memiliki klon harapan nenas yang memiliki kualitas buah unggul, namun produktivitasnya masih rendah. Salah satu kendala dalam meningkatkan produktivitas di lapangan secara agronomi adalah diameter tajuk yang lebar mecapai 1 m, daun yang panjang mencapai 1 m atau lebih, serta kedudukan daun terkulai sehingga memerlukan jarak tanam yang lebar.
Keyword: 

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.
Keyword: