Judul: Karakter Reproduktif Gandum (Triticum aestivum L.) Sensitif Suhu Tinggi pada Aplikasi Putresin di Dataran Sedang dan Tinggi
Abstrak: Wheat (Triticum aestivum L.) is originated from subtropic area. Cultivating wheat in Indonesia faces high temperature stress. Putrescine application may be used to overcome the problem. The objective of this research was to study the effect of putrescine and wheat genotype to the reproductive characters of wheat that were planted in medium (Cisarua) and high (Cipanas) altitudes. The experiment was a factorial experiment with two factors. The first factor was putrescine concentration with 3 levels i.e, 0.0, 1.25, and 2.5 mM. The second factor was three wheat genotypes consisted of Dewata, Munal, and S-03. Putrescine did not affect wheat growth and production. In Cipanas, wheat genotype also affected several reproductive characters, i.e: flowering age, the angle of inflorescence, harvesting time, length of panicle, number of spikelet, number of floret, number of empty floret, and weight of seed per panicle. In Cisarua, wheat genotype affected flowering age, the angle of inflorescence, harvesting time, length of panicle, number of spikelet, number of floret and number of empty floret per panicle. Genotype S-03 is the best genotype to be planted in Cipanas, whereas Dewata is the best genotype to be planted in Cisarua.
Keyword: Triticum aestivum L., sensitive temperature, putrescine, Character reproduktif

Judul: Karakter Morfologi dan Fisiologi Genotipe Gandum (Triticum aestivum L.) Introduksi Toleran Suhu Tinggi di Dataran Tinggi dan Sedang
Abstrak: Wheat (Triticum aestivum) is a member of Gramineae family originated from subtropical regions, that is consumed as a second food in Indonesia, but most of it are imported. Efforts to save foreign exchange from import of wheat is to develop wheat in Indonesia. Planting wheat in Indonesia is facing high temperature stress. Application of putrescine is expected to induce high temperature stress tolerance. This research aimed to study the morphological and physiological respons of two introducted wheat genotypes (Sbr and Astreb) that are tolerant to high temperatures under putrescine application. Wheat was planted in two locations: Cipanas (1100 m asl) and Cisarua (600 m asl) and then was observed the morphological (plant height, number of tillers, number of stomata; angles, thickness and flag leaf area) and physiological characters (chlorophyll content and transpiration rate) to evaluate the effect of 0, 1.25 and 2.5 mM putrescine application. Putrescine treatment in plants significantly affected on the content of chlorophyll a, b and total chlorophyll after 2nd period of putrescine application consentration 2.5 mM in Cipanas. Genotypic differences only affected on adaxial stomatal density after putrescine application in Cipanas, and adaxial stomatal density after 1st period of putrescine application in Cisarua. Genotype Sbr showed better growth in both locations compared with genotype Astreb at high temperature area.
Keyword: Bogor Agricultural University (IPB), Triticum aestivum, putrescine, physiology, morphology

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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