Judul: The significance of mycorrhiza in regeneration of merbau [Intsia bijuga (Colebr.) O. Kuntze] originating from Papua
Abstrak: Merbau [Intsia bijuga (Colebr.) Kuntze] is considered as one of valuable timber tree in South-East Asia which has long been exploited but its silviculture for supporting plantation development is neglected. How to produce good quality of merbau seedlings by using generative and vegetative regeneration methods collaborated with the application of ectomycorrhizal association on merbau for improving the performance of the seedlings is an important issue to be answer. The research was carried out in a series of laboratory experiments and field work (exploration). Exploration was done in merbau natural stands, plantation and nurseries for collecting merbau seeds, wildlings, soils suspiciously containing ectomycorrhizal propagules, sporocarps and ectomycorrhizal root tips of merbau. While experiments to find out the efficient method of merbau regeneration through vegetative and generative propagation were conducted in the laboratory. Merbau was easily regenerated through seeds and shoot cuttings. Merbau seeds revealed variation in morphology and seed weight. Seed nicking followed with seed soaking in low concentration of sodium hypochlorite (0.525 %) for 15 minutes and then in hot water for 24 hours gave the highest percentage of seed germination of merbau (78.67%). Seed weight of > 2.25 g gave better in mean germination time and height performance of the seedlings. The application of auxin IBA/NAA (1000 ppm/500 ppm) gave highest percentage of rooted cuttings (77.1%) and of rooted and sprouted cuttings (50.0%). Merbau regeneration by micro cuttings in vitro was successful to produce explants although the regeneration was in low frequency. The constraints are mainly related to early defoliation of leaves and shoots, and the cessation of the growth after 2 months in the culture medium. Maintaining relatively high concentration of nitrogen and phosphate content close to those of MS medium likely gave beneficial effects for shoot initiation of micro-cuttings of merbau in vitro. Only one species of ectomycorrhizal fungus was found associated with merbau [Intsia bijuga (Colebr.) Kuntze]. The fungus formed mycorrhizae with monopodial pinnate branching type. The fungus was identified belonging to the genus of Scleroderma. The fungus could be cultured in both agar and semi-solid media of MMN. Other ectomycorrhizal fungi i.e. Scleroderma sinnamariense, Scleroderma columnare, Scleroderma. dictyosporum and Pisolithus sp were not able to form ectomycorrhizae with merbau seedlings. Inoculation using both suspension of spore masses and mycelia aggregates of Scleroderma sp did not gave any influences to the cuttings success. On the other hand the inoculation effectively improved the seedling and the transplanted-rooted cutting performance.
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Judul: Potential Combination of Miko-seedcookies and Biological Agents on Merbau Seeds (Intsia bijuga) in Post-mining Land
Abstrak: Penggunaan teknologi direct seeding dengan media tanam Miko-seedcookies (MSC) masih terbatas sehingga perlu ditingkatkan lagi melalui kombinasi dengan agens hayati agar dapat memberikan keberhasilan bagi pertumbuhan tanaman di lahan terdegradasi seperti lahan pascatambang. Penelitian ini bertujuan menganalisis pengaruh aplikasi Miko-seedcookies (MSC), mengetahui dosis agen hayati yang efektif serta mengetahui tingkat serangan hama dan penyakit benih Merbau. Bahan dari penelitian ini terdiri dari agen hayati Gliocladium sp. (Gli) dan Trichoderma hamatum (Tri). Penelitian ini menggunakan rancangan acak kelompok (RAK) dengan satu faktor yaitu dosis agen hayati dengan 3 ulangan dan 4 perlakuan yang terdiri dari MSC, MSC + GliTri 1%, MSC + GliTri 2% dan MSC + GliTri 5%. Hasil penelitian menunjukkan perkecambahan dan daya hidup tidak dipengaruhi oleh media tanam MSC dan dosis agen hayati namun berpengaruh pada tinggi, diameter, jumlah daun serta tingkat serangan hama dan penyakit pada Merbau (Intsia bijuga). Hama dan penyakit yang ditemukan pada tanaman Merbau berupa kutu, hawar daun, bercak daun, dan daun mengkerut dengan intensitas serangan tergolong ringan. Dosis agen hayati 1% dan 2% menunjukkan pengaruh yang paling baik terhadap pertumbuhan tanaman. Persen kolonisasi mikoriza berada pada rentang 16,32%-30% yaitu kelas rendah – sedang., Direct seeding technology with Miko-seedcookies (MSC) planting media is still limited and needs further enhancement by combining biological agents to provide successful plant growth.This study aims to analyze the effect of Miko-seedcookies (MSC) application, determine the effective dosage of biological agents, and assess the level of pest and disease attacks on Merbau seeds. The materials for this study consist of the biological agents Gliocladium sp. (Gli) and Trichoderma hamatum (Tri). This research used a randomized block design (RBD) with one factor,the dosage of biological agents with three replications and four treatments. The results showed that germination and viability were not affected by the MSC planting media and dosage of biological agents. However, they influenced the height, diameter, number of leaves, and the level of pest and disease attacks on Merbau (Intsia bijuga). Pests and diseases found on Merbau plants include aphids, leaf blight, leaf spots, and leaf curling. The 1% and 2% dosages of biological agents showed the best influence on plant growth. The percentage of mycorrhizal colonization ranged from 16.32% to 30%, which is a moderate level.
Keyword: Direct seeding, Glioclaldium sp., Lahan terdegradasi, Mikoriza, Trichoderma hamatum

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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