Judul: Cendawan Mikoriza Arbuskula pada Kecapi (Sandoricum koetjape) di LIPI Cibinong
Abstrak: Research on the association of arbuscular mycorrhizal fungi (AMF) with plants fruits are still rarely done and kechapi (Sandoricum koetjape) is one of the plants that has not been studied. This study aims to identify AMF and arbuscular mycorrhiza structures on kechapi. Spores isolated from the rhizosphere soil samples of kechapi and pot culture. Spores were isolated by wet sieving and decanting method followed by centrifugation then later identified. Observations of arbuscular mycorrhiza structure on roots done by staining using trypan blue then observed structures of arbuscular, coiled hyphae, internal hyphae, and vesicles. The result showed that the percentage infection of roots of kechapi is 36-50%, and the structures of infections in roots of kechapi were coiled hyphae, internal hyphae, and vesicles. The genera of AMF assosiated with kechapi were Acaulospora, Funneliformis, Gigaspora, and Glomus
Keyword: Sandoricum koetjape, Glomus, Gigaspora, Funneliformis, arbuscular mycorrhizal fungi, Acaulospora

Judul: Keanekaragaman Fungi Mikoriza Arbuskula di bawah Tegakan Tanaman Agroforestri Jabon (Anthocephalus cadamba Miq.) di Purwakarta, Jawa Barat
Abstrak: Anthocephalus cadamba is a one of tree species from Rubiaceae family that may symbiotic with arbuscular mycorrhizal fungi (AMF). The presence of AMF is very important for the soil nutrient existence, such as P, K, Mg, Fe, and also Mn to increase the growth of plants. The purpose of this research is to identify the diversity of AMF spores under stand of jabon agroforestry plants and to analyze the AMF status on various jabon planting patterns. Spores isolation was taken from soil sample using wet sieving method and decanthing method. Spores from the isolation morfologically identified by observing spores reaction through Melzer’s liquid. The result of this research indicated that soil chemical characteristic on three planting patterns of jabon do not give any concrete effects to the percentage of AMF’s root colonization. There are three genus of AMF found on the research location consist of Glomus sp., Acalauspora sp., and Scutellospora sp. Based on statistical analysis result, the jabon intercropping planting patterns which combining cucumber plants resulting the highest value of both diameter and height growth on various jabon planting patterns.
Keyword: root colonization, planting pattern, arbuscular mycorrhizal fungi

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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