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: 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: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model