Judul: Tribe Colocasieae (Araceae) in Indonesia
Abstrak: Colocasieae Engler is one of the members of Araceae family which has high economic value. In Malesia, especially in Indonesia Colocasieae consist of 3 genera, Remusatia, Colocasia and Alocasia. Study of Araceae especially on the relationship among members of Colocasieae is still poorly known. A total number of 295 specimens deposited in Herbarium Bogoriense (BO), Singapore Herbarium (SING), Bogor Botanical Garden Herbarium and recent collections from several locations in Indonesia such as Mount Wilis (East Java), Mount Watuwila and Natural Forest Ulungolaka (South East of Sulawesi) and Gunung Leuser National Park, Ketambe (Sumatra, Aceh) were examined using morphological approach. 20 species of Colocasieae are known from Indonesia, consisted of 17 species of Alocasia, two species of Colocasia and one species of Remusatia. The presence of Alocasia flemingiana and Remusatia vivipara in several islands in Indonesia is newly reported. Phylogenetic analysis using Maximum Parsimony indicated that each genus is monophyletic. Alocasia is more closely related to Colocasia while Remusatia forms a different clade. The grouping some species in Alocasia clade supports Hay’s 1991 and 1998 group, although these grouping are not supported by high bootstrap value. The lack of phylogenetic signal in morphological data shows the need for additional informative data, such as molecular data for revealing more robust phylogenetic relationships.
Keyword: Colocasieae, Alocasia, Colocasia, Remusatia, Indonesia

Judul: Perbanyakan in vitro Alocasia suhirmaniana dan analisis keragaman genetik Alocasia grup Longiloba koleksi Kebun Raya Bogor
Abstrak: Alocasia suhirmaniana (Araceae) is a new species of genus Alocasia with beautiful leaves. This plant grows endemic in South-East Sulawesi. Alocasia suhirmaniana collected from Taman Wisata Alam Mangolo, Kolaka, South-East Sulawesi has been grown at the Centre of Plant Conservation, Bogor Botanic Garden-LIPI. This plant is now difficult to be found in their original area and considers as endangered species. Therefore, conservation and multiplication of its domestication is needed. The aim of the research was to establish a protocol for in vitro propagation from bud explant
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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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