Judul: Leaf Anatomy of Several Local Starfruit (Averrhoa carambola L.) varieties in Mekarsari Fruit Garden, Bogor
Abstrak: Belimbing manis (Averrhoa carambola L.) menjadi salah satu tanaman buah yang digemari oleh masyarakat Indonesia karena memiliki rasa manis dan aroma yang khas. Taman Buah Mekarsari mengembangkan beberapa varietas belimbing manis di antaranya Demak Jingga, Demak Kapur, Demak Kunir, Sembiring, Bangkok, Filipina, Dewi, Wulan, Malaya, Penang, Welahan, dan Rawasari. Secara anatomi, karakter mengenai tanaman belimbing manis lokal belum banyak diketahui sehingga penelitian ini bertujuan mengamati struktur anatomi daun lima varietas belimbing manis lokal di Taman Buah Mekarsari. Bahan yang digunakan yaitu daun belimbing lima varietas lokal yaitu varietas Demak Jingga, Demak Kapur, Demak Kunir, Welahan, dan Wulan. Daun dari lima varietas belimbing manis lokal dibuat sediaan mikroskopis berupa sayatan paradermal dengan metode whole mount serta sayatan transversal dengan metode parafin. Hasil pengamatan sayatan paradermal daun belimbing manis menunjukan tipe dinding sel epidermis yaitu berlekuk lurus dan berlekuk dangkal dengan bentuk sel epidermis bersegi empat, bersegi lima, dan bersegi banyak. Stomata daun lima varietas belimbing manis yang diamati memiliki tipe stomata yang sama yaitu parasitik. Hasil perhitungan nilai indeks, ukuran, dan kerapatan stomata beragam antar varietas. Kerapatan dan indeks stomata tertinggi dijumpai pada varietas Welahan. Trikoma yang teramati yaitu trikoma non kelenjar uniselular. Hasil sayatan transversal daun belimbing manis menunjukkan bagian daun yang teramati terdiri dari lapisan kutikula, epidermis atas, jaringan palisade dan bunga karang serta epidermis bawah berupa papil. Kelima varietas tanaman belimbing manis lokal memiliki jaringan mesofil bertipe dorsiventral. Varietas Wulan memiliki daun dan jaringan mesofil yang cendrung lebih tebal dibandingkan dengan varietas yang lainnya., Sweet star fruit (Averrhoa carambola L.) is one of the most popular fruit plants in Indonesia because of its sweet taste and distinctive aroma. Mekarsari Fruit Garden develops several varieties of sweet starfruit including Demak Jingga, Demak Kapur, Demak Kunir, Sembiring, Bangkok, Filipina, Dewi, Wulan, Malaya, Penang, Welahan, and Rawasari. Anatomically, the characters of local sweet star fruit plants are not widely known so this study aims to observe the anatomical structure of the leaves of five local sweet star fruit varieties in Mekarsari Fruit Garden. The materials used were star fruit leaves, five local varieties, including Demak Jingga, Demak Kapur, Demak Kunir, Welahan, and Wulan. The leaves of five local sweet star fruit varieties were made microscopic preparations in the form of paradermal incisions using the whole mount method and transverse incisions using the paraffin method. The observation result of the paradermal incision of sweet star fruit leaves shows that the type of epidermal cell wall is straight and shallow grooved with rectangular, five-sided, and multi-faceted epidermal cells. The leaf stomata of five sweet star fruit varieties were observed to have the same type of stomata, namely parasitic. The results of the calculation of the index value, size and density of stomata varied between varieties. Demak Kunir has the largest stomata size with a low density. The highest stomata density and index were found in the Welahan variety. The trichomes that were observed were unicellular gland trichomes. The results of the transverse incision of sweet starfruit leaves showed that the observed leaf parts consisted of a layer of cuticle, epidermis, palisade tissue and sponges and
Keyword: Averrhoa carambola L., characterization, stomata index, trichomes

Judul: Karakterisasi Morfologi dan Anatomi Tanaman Belimbing Manis (Averrhoa carambola L.) di Taman Buah Mekarsari Bogor.
Abstrak: Belimbing manis di Indonesia memiliki berbagai macam varietas yang masing-masing memiliki ciri khas tersendiri. Karakterisasi morfologi maupun anatomi terhadap tanaman belimbing manis belum banyak dilakukan sehingga karakter mengenai tanaman belimbing manis belum banyak diketahui. Tujuan penelitian ini adalah mendeskripsikan karakter morfologi dan anatomi serta melengkapi data tanaman belimbing manis di Taman Buah Mekarsari. Metode yang dilakukan adalah penentuan sampel, pengamatan karakter morfologi dan anatomi, dan pengamatan data sekunder tanaman. Karakter morfologi masing-masing varietas yang diamati menunjukkan ciri khas yang berbeda-beda. Morfologi buah merupakan karakter paling dominan dalam menjelaskan perbedaan pada masingmasing varietas. Karakter anatomi pada dua varietas terpilih (Malaya dan Sembiring) menunjukkan kesamaan pada stomata yang bertipe parasitik dan trikoma yang bertipe uniselular.
Keyword: anatomi, belimbing manis (Averrhoa carambola L.), morfologi

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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