Judul: Pengaruh Pematahan Dormansi Terhadap Kemampuan Perkecambahan Benih Angsana (Pterocarpus Indicus Will)
Abstrak: INTRODUCTION. So far, Seedling production of Angsana (Pterocarpus indicus Will) is done by stem cutting. Seedling propagation by seeds is not done widely, as well as its silvicultural system is still not known yet. Seed germination percentage is affected strongly by seed quality (physic, genetic and physiology). The main problem of seed germination of Angsana seeds is seed coat dormancy; therefore it is important to study the breaking dormancy techniques of Angsana seeds. The aim of this research was to study the effects of breaking dormancy treatment to the germination capacity of Angsana seeds. MATERIAL AND METHOD. This research was done from 30 June to 28 Agust 2008 at Green House, the Laboratory of Silviculture, Faculty of Forestry, Bogor Agricultural University. The material and equipment used in this experiment consisted of Angsana seeds, hot water, H2SO4, KNO3, water from fermented bamboo shoots (Gigantochloa apus Kurz), rice hull charcoal, subsoil, germination boxes, soaking bath, watering equipment, analytical balance, stationary, ruler, calliper, and digital camera. The research procedures consisted of several steps; those were seed extraction and selection, seed water content measurement, breaking dormancy treatments, germination, maintenance, observation, and data collection and analysis. The experimental design in this research was completely randomised design which consisted of 6 soaking treatments, those were soaking in hot water for 30 minutes followed by soaking in cold water for 12 hours (B0), soaking in the fermented bamboo shoot liquid for 12 hours (B1), soaking in H2SO4 1% for 10 minutes (B2), soaking in H2SO4 1 % for 15 minutes (B3), soaking in KNO3 1 % for 12 hours (B4) and soaking in KNO3 for 24 hours (B5). Each experiment unit was replicated in three replicates. The observed parameters consisted of germination capacity, germination value, speed of germination, germination rate, germination time at 80%, high and diameter of transplanted seedlings. The collected data was analysed using F test followed by Duncan Multiple Range Test (DMRT). RESULTS AND CONCLUSSION. Angsana seeds had embryonic and seed coat dormancies. Based the results of F test and Duncan test showed that soaking in H2SO4 1% for 10 minutes and in KNO3 1 % for 24 hours could break those dormancies. It was indicated by it high germination percentage (100 %), and other values such as germination value (1,13% to 1.05% normal germinants/day2), germination speed (1, 41 %/day), germination rate (19,32 – 18,59 day), germination time at 80% (25 day), seedlings height (1,53 cm) , and diameter growth (1,06 mm to 1,1 mm) respectively. Key word: Angsana, Pterocarpus indicus Will, Dormancy.
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Judul: Dormancy Breaking Methods of Ketapang Kencana (Terminalia mantaly) Seeds
Abstrak: Budidaya ketapang kencana secara generatif memiliki kendala karena adanya dormansi benih, sifat dormansi ini dapat dihilangkan melalui metode pematahan dormansi untuk memperbaiki viabilitas dan vigor benih. Penelitian bertujuan menganalisis metode pematahan dormansi yang tepat untuk benih ketapang kencana. Perlakuan pematahan dormansi yang diterapkan adalah: (1) kontrol, (2) benih dipotong, (3) benih diampelas, (4) benih direndam dalam larutan H2SO4, (5) benih direndam air panas, (6) benih direndam air 12 jam, (7) benih direndam air 72 jam. Hasil penelitian menunjukkan terdapat tiga perlakuan yang tepat yaitu pemotongan, pengampelasan dan perendaman benih dalam air selama 12 jam. Perlakuan pematahan dormansi berpengaruh nyata terhadap indeks perkecambahan, pertumbuhan kecambah normal (berat kering, tinggi kecambah, panjang akar) dan awal mula tumbuh kecambah. Benih berukuran besar memiliki indeks perkecambahan, potensi tumbuh maksimum, daya berkecambah, vigor benih dan berat kering kecambah lebih tinggi dibandingkan dengan benih yang berukuran lebih kecil., The generative cultivation of Ketapang Kencana has problems due to seed dormancy, this dormancy can be removed through the dormancy breaking method to improve seed viability and vigor. This study aims to analyze the appropriate dormancy breaking methods for Ketapang Kencana. The dormancy breaking treatments applied were: (1) control, (2) seeds cut, (3) seeds sanded, (4) seeds soaked in H2SO4 solution, (5) seeds soaked in hot water, (6) seeds soaked in water 12 hours, (7) seeds soaked in water 72 hours. The results showed that there were three appropriate treatments, cutting near the growing point, sanding, and soaking the seeds in water for 12 hours. The treatment of breaking dormancy had a significant effect on germination index, normal germination growth (dry weight, sprout height, root length), and early germination. Seed size affects germination and dry weight of normal germination. Large seeds had a higher germination index, maximum growth potential, germination capacity, seed vigor and dry weight of germination compared to smaller seeds.
Keyword: seed dormancy, seed germination, seed size, seed vigor, Terminalia mantaly

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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