Judul: Pruning Akar untuk Meningkatkan Kolonisasi Ektomikoriza pada Bibit Melinjo (Gnetum gnemon) Umur 2 Bulan
Abstrak: Melinjo seedling inoculation with ectomycorrhizal fungi should be done when the seedlings are still young, to get the seedlings with the high colonization. Ectomycorrhizal colonization on the young melinjo seedlings (age 2 months) perhaps can be improved by root pruning. Objective at the research is to study the effect of root pruning toward the increasing of ectomycorrhizal colonization and melinjo seedling growth (age 2 months). The research used split plot design. Source of ectomycorrhizal inoculum as main plots consisted of 3 levels, i.e. control, ectomycorrhizal seedling, and soil inoculum. Root pruning as sub plots consisted of 3 levels, i.e. 0%, 30%, and 50%. The results showed that root pruning can improve the root system of melinjo seedlings through the increasing of branching roots and could increase ectomycorrhizal colonization. Root pruning at 50% level that combined with soil inoculum more effective to increase rate of ectomychorrhizal colonization compared with other treatments. Increasing of ectomychorrhizal colonization did not significantly improving the growth of melinjo seedling.
Keyword: root pruning, Gnetum gnemon, ectomychorrhizal

Judul: Pengaruh Penambahan Media Tanam terhadap Keberhasilan Aplikasi Pangkas Akar dan Inokulasi Fungi Ektomikoriza pada Bibit Melinjo
Abstrak: Root pruning has been known to fix root’s root system and enhancing ectomycorrhiza colonization in 2 months old melinjo seeds, but during 6 months of observation, it is not giving any significant effect to enhance growth of seedlings. This research aimed to determine the effect of replenishment of planting media and time of observation to the success rate of ectomycorrhiza fungal infection and the growth of inoculated melinjo seedlings after 8 months. Planting media replenishment affected the growth of roots and shoots of the observed melinjo seedlings. Planting media replenishment shown its influence to the growth of melinjo seedlings at the 3rd month of after weaned. Root pruning is no longer giving a significant effect, either to ectomycorrhiza colonization or melinjo seedlings growth. Fungi’s ectomycorrhiza inoculation enhance the growth of melinjo seedlings.
Keyword: Bogor Agricultural University (IPB), Ectomycorrhiza, Gnetum gnemon, Planting media, Root pruning

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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