Judul: Barcoding DNA Study of Diospyros spp. in Malesian Region
Abstrak: Diospyros spp. di kawasan Malesia memiliki keanekaragaman yang tinggi dan berpotensi sebagai komoditi ekonomi. Namun, banyak Diospyros spp. yang belum teridentifikasi dan kurang tepat dalam identifikasi serta penamaannya sehingga keanekaragaman tersebut perlu dikonfirmasi. Identifikasi hingga tingkat jenis pada marga Diospyros spp. sulit dilakukan karena keberadaan organ generatif (bunga dan buah) jarang ditemukan sedangkan organ generatif merupakan ciri pembeda yang biasa digunakan untuk identifikasi jenis dari marga Diospyros spp. Pendekatan DNA barcoding pada daun dapat digunakan dalam identifikasi jenis spesimen hidup Diospyros spp. di kawasan Malesia. Tujuan dari penelitian ini untuk memberikan informasi mengenai keanekaragaman Diospyros spp. di kawasan Malesia melalui pendekatan DNA barcoding dan mengungkapkan informasi filogeni Diospyros spp. di kawasan Malesia. Penelitian dilaksanakan pada bulan Mei 2020 hingga Februari 2021 di Laboratorium Molekuler Pusat Penelitian Konservasi Tumbuhan dan Kebun Raya, LIPI. Sampel Diospyros spp. diambil dari koleksi Kebun Raya Bogor. Prosedur pengamatan DNA barcoding meliputi empat tahap utama yaitu ektraksi DNA, amplifikasi, visualisasi DNA dan produk PCR, serta sekuensing. Primer barcoding yang digunakan berasal dari plastida trnL-F intergenic spacer (IGS). Data sekuen DNA barcoding dianalisis menggunakan perangkat lunak BioEdit untuk proses konstruksi konsensus sekuen. Selanjutnya dilakukan data mining melalui BLAST secara online untuk identifikasi kemiripan sekuen berdasarkan database yang terdapat di National Center for Biotechnology Information (NCBI), Multiple alignment sequences melalui multiple sequence comparison by log-expectation (MUSCLE) dan konstruksi pohon filogenetik dengan metode Maksimum Parsimoni (MP) dan algoritma Tree-Bisection-Regrafting (TBR) yang dilakukan menggunakan perangkat lunak MEGA X dengan pairwise deletion option dan bootstrap 1000x. Konstruksi pohon filogenetik menggunakan 20 aksesi Diospyros spp yang disekuensing, 40 aksesi sekuen Diospyros spp. hasil BLAST dan empat outgroup berasal dari database NCBI. Keanekaragaman Diospyros spp. di kawasan Malesia telah diungkapkan terhadap 20 aksesi yang mewakili 18 jenis Diospyros. melalui pendekatan DNA barcoding dengan menggunakan primer trnL-F IGS. Sepuluh jenis Diospyros merupakan informasi sekuen baru yang dipublikasikan di Kawasan Malesia. Berdasarkan lokasi asal aksesi, Diospyros paling banyak ditemukan di Pulau Jawa (6 aksesi) dan Sulawesi (5 aksesi), sedangkan yang paling sedikit ditemukan di Pulau Sumatra dan Filipina, masing-masing satu aksesi. Validasi pada 20 aksesi Diospyros dengan data sekuen pada GenBank menunjukkan adanya hubungan kekerabatan dengan 44 jenis Diospyros lainnya di dunia. Rata-rata frekuensi nukleotida pada sekuen trnL-F IGS dalam Diospyros spp. adalah 34,7 % (T), 21,0 % (C), 29,2 % (A), dan 15,0 % (G). Analisis filogenetik menggunakan metode maksimum parsimoni dan 1000 ulangan bootstrap pada 68 DNA sekuen (64 Diospyros spp. dan empat outgroup) menghasilkan satu pohon filogeni yang kokoh dengan nilai consistensy index (CI) 0,82 dan retention index (RI) 0,89. Semua Diospyros spp. yang dianalisa membentuk satu kelompok monofiletik dan selanjutnya terbagi menjadi tujuh klada. Ketujuh klada ini memperbarui data filogenetik Diospyros di Kawasan Malesia. Hipotesis kedekatan biogeografi mendukung hasil filogenetik. Distribusi jenis dalam klada ditentukan berdasarkan kemiripan basa nukleotida dan juga dapat dikelompokkan berdasarkan sebaran dari Diospyros tersebut: Kawasan Malesia (klada I dan V), Kawasan Malesia-Kaledonia (klada III dan IV), Kosmopolit hampir di semua bioregion (klada II, VI dan VII).
Keyword: eboni, filogeni, Malesia

Judul: Pemoposan sebagai Bukti Taksonomi Jenis-jenis Diospyros (Ebenaceae)
Abstrak: People tend to use generative structures for plant identification. Nevertheless, generative structure availibility limits the identification practice for a plant with once-a-year fruit-bearing-phase, such as Diospyros L. Being vegetative characters, leaf flushing are rarely used for plant identification so that they have not been explored as a taxonomic evidence. In this paper, leaf flushings and their taxonomic implication were studied using eight species of Diospyros grown in Ecopark of Cibinong Science Center LIPI, Bogor. This study explored Diospyros leaf flushing, including the following: 1) morphological developments, 2) phenology, 3) morphological variations, 4) taxonomic implication, and 5) phenetic relationships. Morphological and phenological data was observed on eight species of Diospyros with 22 qualified individual trees. Data obtained then descriptively and phenetically analized. Arrested growth in the development of Diospyros bud produce a rhythmic growth. After a dormant period, bud broke and produced a flushing set before finally back to its dormancy. Diospyros flushing set was usually distinguishable from the previous one by cataphyll scars at the twigs and the pattern of phytomer in a flushing set (leaf size, the length internodus and petiole), except on D. buxifolia which the phytomer was uniform and the cataphylls were very small and sometimes absent. Dorsal cataphyll only found in D. jaherii. The presence of small reduced leaf due to an arrested growth also can be used to indicate the base of flushing set in D. blancoi dan D. jaherii. The time of bud broken was not simultaneous in all Diospyros species, all individual trees within the same species, even in all buds of an individual tree under similar external condition. Diospyros have a seasonal growth pattern, except for D. jaherii. A mature flushing set was formed in 40-55 days. Leaves of Diospyros observed were arranged alternately and have equitant vernation. Leaf flushing provided 39 characters (included bud, young leaves, mature leaves, and flushing set characters) that can be used as taxonomic evidence for distinguishing eight species of Diospyros observed. A determination key for these species solely based on leaf flushing characters is presented. Dendrogram obtained showed that leaf flushing characters were capable to divide individuals observed as well as their species at the coefficient of similarity 76%. The most similar species were D. blancoi and D. celebica (74%). Both of them are belongs to subgenus Eudiospyros (L.) Bakh., section Ebenaster Bakh. The cophenetic correlation value obtained was 0,98 or very good fit (Rohlf 1998). Two principal coordinate analysis used shows the diversity of 26,79% and divided Diospyros into three groups. Group I contained D.malabarica, D. beccarioides, D. cauliflora and D. pilosanthera. Group II cotained D. blancoi, D. celebica dan D. jaherii. Group III contained D. buxifolia. Flushing characters seems to be varied and can be used as field identification of Diospyros observed. Thus, leaf flushing was proved capable as a taxonomic evidence for Diospyros species observed.
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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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