Judul: Cendawan Mikoriza Arbuskula pada Pohon Bisbul (Diospyros blancoi) di Bogor
Abstrak: Bisbul (Diospyros blancoi) fruit is edible and could be potent inhibitors of the ageing process in the skin. Study on arbuscular mycorrhizal fungi (AMF) of bisbul has never been reported, while most of root plants associated with AMF. The general objective of this study was to observe the AMF colony and AMF spore in the rhizophere of bisbul tree and attempt to pot culture with Pueraria javanica as the host plant. Root and soil samples from rhizosphere of bisbul were taken from three locations, i.e Kampus IPB Darmaga, Cibinong, dan Ciampea. Roots were stained by using of trypan blue 0.05%. Soil samples were air dried, then part of it used for spore isolation and other part for pot culture. Spores were separated by using wet sieving and decanting method and continued with centrifugation. The result showed that bisbul roots have arbuscules, vesicles, coiled hypha, and internal hypha of AM. AMF spores isolated from bisbul rhizosphere were Acaulospora scrobiculata, Acaulospora tuberculata, Gigaspora spp., Glomus spp., and Scutellospora sp
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Judul: Cendawan Mikoriza Arbuskula pada Sawo Duren (Chrysophyllum cainito) di Kampus IPB Darmaga
Abstrak: Arbuscular mycorrhizal fungi (AMF) are soil fungi that symbiosis with the plant roots. Research about AMF on fruit plants are rarely reported. The objectives of this research are to identify AMF spore and to detect the structure of arbuscular mycorrhiza (AM) on star apple. AMF spore was isolated from the star apple rhizosphere soil following the wet sieving and decanting method and centrifugation, and then identified based on shape, color, size, and spore wall ornamentation. The AM structure was observed on colored root using trypan blue. The result of the research showed that AMF was associated with star apple. The structures of AM in the roots of star apple were internal hyphae, coiled hyphae, and vesicles. The percentage of AM infection in the star apple’s root was 12-31 %. The AMF spores found in the star apple rhizosphere were Acaulospora bireticulata, A. scrobiculata, Ambispora cf. fecundisporum, Funneliformis cf. geosporum, Glomus cf. aggregatum, Glomus cf. microaggregatum, Glomus sp. 1, and Glomus sp. 2.
Keyword: Acaulospora, Ambispora, arbuscular mycorrhiza, Chrysophyllum cainito, Funneliformis, Glomus

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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