Judul: Teknik Perbanyakan dan Kekerabatan Genetik Pasak Bumi (Eurycoma longifolia Jack)
Abstrak: Pasak bumi (Eurycoma longifolia Jack) is a shrubs growing wildly in the forests of Southeast Asia and widely used throughout the region because of its medicinal properties. Uncontrolled harvesting of wild-grown trees has led to rapid decrease of natural populations, as well as causing a potential decrease in genetic diversity. The objectives of this research were 1). To get information about propagation technique of pasak bumi by seed and stem cutting and its suitable growing medium and 2). To estimate genetic relatedness of pasak bumi propagated by seed collected from Jambi using RAPD marker. Propagation by seed produced low germination percentage (14-34%) at different media. Seedling planted in pure carbonized rice husk medium produced the best growth variabel on vigority, primary root number, secondary root number, primary root length and secondary root length. Result from stem cutting showed that medium significantly improved secondary root length, while rooting percentage, primary root length and the number of root significantly was affected by Rootone F treatment. Genetic relatedness by RAPD marker showed that pasak bumi propagated by seed has high value of genetic diversity within population (He = 0,3076) and 78,57% all the loci tested were polimorphic, clustering analysis showed that the plant can be grouped into two group.
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Judul: Kajian ekologis pasak bumi (Eurycoma longifolia Jack.) di pusat kajian hutan tropika areal HPH Pt. Siak Raya Timber, Riau
Abstrak: Pasak bumi merupakan tumbuhan obat yang mempunyai banyak kegunaan. Di Indonesia, tumbuhan ini sudah mulai melangka karena penyebarannya yang terbatas (Kalimantan dan Sumatera) dan pemanenan secara langsung dari alam untuk bahan baku industri jamu. Berdasarkan pustaka, penelitian mengenai aspek ekologi pasak bumi belum pernah dilakukan. Diharapkan dari hasil penelitian ini dapat memberikan data dasar ekologi dalam upaya penangka- ran/pembudidayaan dan pelestariannya. Tujuan dari penelitian ini adalah untuk mengetahui karakteristik ekologis dari tumbuhan pasak bumi. Adapun komponen ekologis yang diamati yaitu komposisi jenis tumbuhan penyusun vegetasi, tanah yang mendukung kehidupan vegetasi, kondisi fisiografi lapangan, kondisi iklim, sifat toleransi terhadap cahaya, kondisi populasi serta pengaruh aktifitas manusia. Penelitian dilakukan melalui pengamatan terhadap kondisi tumbuhan pasak bumi dan hubungan semua faktor lingkungan yang diduga berpengaruh terhadap pertumbuhan dan penyebaran jenis tersebut. Hasil analisis faktor- faktor yang diamati disajikan secara deskriptif. Faktor biotik yang mempengaruhi pertumbuhan dan penye- baran pasak bumi adalah komunitas vegetasi hutan, mikro Sorganisme tanah (mikoriza) dan manusia, sedangkan faktor abiotiknya adalah tanah, kondisi fisiografis, mataheri, suhu dan kelembaban. sinar Suhu tempat tumbuh pasak bumi berkisar antara 23,5°C - 34,0°C. Kelembaban berkisar antara 62% - 98%. Pasak bumi didapati tumbuh pada tanah yang miskin hara dengan pH tanah asam sampai sangat asam. Tekstur tanah lempung liat berpasir, lempung berliat dan lempung berpasir. Dengan memanfaatkan mikoriza, tumbuhan ini dapat meningkatkan efektifitas dalam penyerapan unsur hara. Anakan pasak bumi memerlukan naungan, sedangkan pada tingkat belta dan pohon memerlukan banyak sinar matahari secara langsung untuk pertumbuhan diameter, pembentukan cabang dan organ generatifnya..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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