Judul: Colonization dynamics of three ectomycorrhizal fungi scleroderma spp. and their role on host plant growth
Abstrak: Ectomycorrhizal symbiosis represented one of the most important mutualistic association in forest ecosystem. Scleroderma spp. have already been known as ectomycorrhizal fungi which could form symbioses with Dipterocarpaceae, Pinaceae, and Gnetaceae. This study was conducted in three steps, (1) Compatibility test of three ectomycorrhizal fungi Scleroderma spp. under in vitro condition. The aim of this study was to determine the mycelial antagonism and interaction patterns among the fungus under in vitro condition. Three species Scleroderma spp. were cultured on solid Modified Melin Norkrans (MMN) medium. Each fungus was cultured as single, pairs and triple combinations. A completely randomized design were used with 7 treatments and 8 replicates Petri dishes. We found that the radial growth of S. sinnamariense mycelia was two times faster than S. columnare and S. dictyosporum. There was no antagonism pattern between fungal mycelia when they grown together. (2) Colonization dynamics of three ectomycorrhizal fungi Scleroderma spp. and their relation to host plant growth. The aim of this study was to determine the compatibility and specificity of each ectomycorrhizal fungi with the host plants, and the effect on host plants growth. S. columnare, S. dictyosporum and S. sinnamariense were inoculated in single-, two-, and three- species treatments to Shorea pinanga, Pinus merkusii and Gnetum gnemon seedlings using spores suspension. After 6, 8, and 10 months of inoculation, seedlings were harvested to determine colonization percentage, height and diameter growth, and plant biomass. The results revealed that S. sinnamariense did not form association with S. pinanga and P. merkusii but form association with G. gnemon. On the other hand, S. columnare and S. dictyosporum both in single- and multi- species treatments could form association with all the host plants. Generally, Scleroderma spp. increased the growth of host plants. The last was (3) Root characteristics of ectomycorrhizal fungi on S. pinanga, P. merkusii, and G. gnemon. The aim of this study was to determine the morphology (hyphae colour, branching pattern, clamp-connection) and anatomy (mantel and Hartig net) of ectomycorrhizal roots in each host plants which associated with the ectomycorrhizal fungus. This result revealed that morphology were affected by fungi, while branching pattern and Hartig net were affected by plants. S. pinanga dan G. gnemon were have monopodial branching pattern which P. merkusii was dichotomously branching pattern. The depth of mantels and Hartig net were increase by time. The Hartig net was only at epidermis S. pinanga and G. gnemon, while its penetrated in cortex on P. merkusii., Fungi ektomikoriza memainkan peranan penting dalam berbagai ekosistem, melalui keterlibatannya dalam siklus karbon dan nutrisi, jejaring makanan di bawah tanah, serta dinamika komunitas tanaman. Fungi ektomikoriza merupakan salah satu komponen penting dalam ekosistem hutan, dan diketahui membentuk simbiosis dengan sebagian besar tanaman kehutanan. Scleroderma merupakan genus fungi ektomikoriza yang diketahui dapat membentuk simbiosis dengan Dipterocarpaceae, Pinaceae, dan Gnetaceae. Simbiosis dengan fungi ektomikoriza akan membantu pertumbuhan dan ketahanan hidup tanaman inang karena fungi ektomikoriza akan membantu dalam penyerapan unsur hara dan air, meningkatkan ketahanan terhadap patogen dan meningkatkan ketahanan terhadap kekeringan. Beberapa fungi ektomikoriza juga menghasilkan tubuh buah yang dapat dikonsumsi (edible mushroom). Penelitian ini dilaksanakan
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Judul: Identifikasi dan isolasi cendawan ektomikoriza Scleroderma Pers.
Abstrak: Telah berhasil diidentifikasi tiga spesies Scleroderma dari hutan Haur Bentes, Jasinga; Kebun Percobaan Cikarawang, Fakultas Kehutanan, Institut Pertanian Bogor; dan halaman rumah di Bogor. Scleroderma yang ditemukan dari tegakan Hopea odorata, H. mengarawan, Shorea leprosula, S. stenoptera ialah Scleroderma columnare, sedangkan dari tegakan Pinus merkusii ialah S. dictyosporum dan dari tegakan Gnetum gnemon ialah S. sinnamariense. Sebuah basidioma S. columnare juga ditemukan tumbuh pada kayu yang melapuk. Dari lima macam medium yang digunakan untuk mengiso- lasi basidioma Scleroderma, pertumbuhan hanya terjadi pada medium Hagem saja. Setelah dua minggu, pertumbuhan terhenti pada saat koloni mencapai diameter 6 mm…dst
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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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