Judul: Pollen Morphology of Legume Plants in IPB University Campus, Dramaga
Abstrak: Tumbuhan berbunga menghasilkan polen dengan karakter morfologi yang bervariasi. Informasi mengenai polen dapat digunakan untuk identifikasi, penelitian genetika, sumber bukti taksonomi, serta perubahan evolusi pada tumbuhan. Penelitian ini bertujuan mendeskripsikan karakter morfologi polen yang berasal dari tumbuhan legum di kampus IPB, Dramaga. Pengamatan morfologi polen dilakukan terhadap 20 spesies tumbuhan dari famili Fabaceae. Pengambilan dan pengoleksian bunga dilakukan dengan metode jelajah di beberapa wilayah kampus IPB, Dramaga. Sediaan mikroskop sampel polen dibuat dengan metode asetolisis standar. Karakter morfologi polen yang diamati meliputi unit polen, bentuk polen dari sisi polar dan ekuatorial, indeks P/E, ukuran polen, tipe aperture, dan ornamentasi eksin. Hasil penelitian menunjukkan bentuk polen dari sisi polar dan ekuatorial pada sebagian spesies tumbuhan legum berupa circular dan circular oval. Ukuran polen yang diamati sangat bervariasi yaitu berukuran sangat kecil hingga sangat besar. Hasil pengukuran polen berdasarkan indeks P/E memiliki nilai >1,00. Tipe aperture yang dijumpai sangat bervariasi meliputi monoporate, tetraporate, tricolpate, tricolporate, dan triporate. Ornamentasi eksin yang ditemukan berupa psilate, reticulate, dan scabrate. Kata kunci: aperture, asetolisis, Fabaceae, ornamentasi eksin, ukuran polen, Flowering plants produce pollen with varied morphology characteristics. Pollen information can be used for identification, genetic research, taxonomic evidence sources, and evolutionary changes in plants. This study aimed to identify the pollen morphology characteristic of legume plants from the IPB campus, Dramaga. Pollen grains morphology observations were carried out on 20 species of the family Fabaceae. The collection and collection of flowers are carried out by the roaming method in several areas of the IPB campus, Dramaga. Pollen sample microscopy was prepared by the acetolysis standard method. The morphological characters of pollen grain observed were pollen unit, pollen shape from polar and equatorial view, P/E index, pollen size, aperture type, and exine ornamentation. The observations result showed that the pollen shape from the polar and equatorial of some species of legumes plant was circular and circular oval. The size of pollen grains varied greatly, from very small to very large sized. The results of the pollen measurement based on the P/E index had a value >1.00. The types of aperture found varied including monoporate, tetraporate, tricolpate, tricolporate, and triporate. Exine ornamentation is found in the form of psilate, reticulate, and scabrate. Keywords: acetolysis, aperture, exine ornamentation, Fabaceae, pollen size
Keyword: acetolysis, aperture, exine ornamentation, Fabaceae, pollen size

Judul: Diversity of Reproductive Structures in Epiphytic Ferns in the Campus Area of IPB, Dramaga, Bogor
Abstrak: Institut Pertanian Bogor merupakan kampus dengan biodiversitas tinggi. Tumbuhan paku epifit menjadi salah satu tumbuhan yang sangat melimpah jumlah dan jenisnya, tetapi informasi struktur reproduksinya masih terbatas. Penelitian ini bertujuan mengkarakterisasi struktur reproduksi tumbuhan paku epifit yang tumbuh di kawasan kampus IPB, Dramaga, Bogor. Metode penelitian terdiri dari koleksi sorus, pengawetan dengan alkohol 70%, pengamatan menggunakan mikroskop majemuk yang dihubungkan pada kamera optilab, dan pengukuran menggunakan aplikasi imageRaster v2.1. Tumbuhan paku epifit yang diamati bervariasi pada susunan dan letak sorus serta ciri sporanya. Sorus berbentuk bulat dan garis. Sebagian besar sorus terletak pada tepi daun. Sebanyak 22 jenis tumbuhan paku yang memiliki spora bentuk monolete dengan laesura garis, satu jenis bentuk bulat, dan satu jenis bentuk tetrahedral-globose dengan laesura triradiate. Ukuran spora yang dijumpai yaitu medium, besar dan sangat besar. Semua spora memiliki nilai rasio P/E ≤1,00 dengan tipe peroblate, oblate, suboblate, oblate bulat dan prolate bulat. Permukaan perispora sangat beragam yaitu alate-angular, globules, shallow verrucae, verrucate, echinulate, tuberculate, rugate, globules, echinate, laevate, cristate, regulate, colliculate, granulose, dan costate-alate., Bogor Agricultural University is a campus with high biodiversity. Epiphytic ferns are one of the most abundant plants in terms of numbers and types, but information on their reproductive structures is still limited. This study aims to characterize the reproductive structure of epiphytic ferns that grow in the IPB campus area, Dramaga, Bogor. The research method consisted of a collection of sorus, preserving it with 70% alcohol, observing using a compound microscope connected to an optilab camera, and measuring using the imageRaster v2.1 application. The observed epiphytic ferns varied in the arrangement and location of the sorus and the characteristics of the spores. The sorus was round and line. Most of the sorus were located on the leaf margins. A total of 22 fern species had monolete spore with line laesura, one species had round spore, and one species had tetrahedral-globose spore with triradiate laesura. Spore sizes found were medium, large, and very large. All spores had a P/E ratio value of ≤1.00 with peroblate, oblate, suboblate, round oblate, and round prolate types. The surface of the perispora is very diverse, namely alate-angular, globules, shallow verrucae, verrucate, echinulate, tuberculate, rugate, globules, echinate, laevate, cristate, regulate, colliculate, granulose, and costate-alate.
Keyword: biodiversity, characterization of spores, perispore surface, sorus

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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