Judul: Adaptation of taro (Colacasia esculenta (L.) Schoot) at different soil water availability
Abstrak: Indonesia is one of the countries with the greatest diversity of taro variety, while the study of taro's morphology and nutritional characteristics is limited. The aim of this study was to evaluate the anatomical of plant and nutritional value of taro tuber. This research observed fourteen genotypes of Colacasia esculenta (7 Eddoe types, 7 Dasheen types) and 3 Xanthosoma genotypes. In three blocks of replications, the eddoe and Xanthosoma genotypes were cultivated using cormel and the dasheen genotypes with sucker. Plant anatomy (leaf, stem, and root) and tuber nutritional characteristics were analyzed. From this research, explained that stomata and epidermis number, length from stomata and epidermis, number leaf epidermis, length of leaf and stem epidermis, also length of root epidermis, endodermis, cortex, and stele among 17 genotypes of taro were statistically different. The diversity of taro based on the nutrition content of tuber between 17 genotypes of taro was considered high, as represented by water, ash, fat, protein, carbohydrate, energy, and glucomannan, which were statistically different.
Keyword: keragaman, perubahan iklim, TALAS; CEKAMAN. AIR, KEKERINGAN, GENANGAN, TALAS, AIR

Judul: Adaptasi Tanaman Talas (Colacasia Esculenta (L.) Schoot) Terhadap Perubahan Ketersediaan AIr Tanah
Abstrak: Tujuan dari penelitian ini adalah untuk mengetahui mekanisme adaptasi dan respon genotipe talas pada berbagai tingkat ketersediaan air tanah. Penelitian ini dilakukan dengan menggunakan rancangan petak terbagi dengan petak utama adalah tingkat ketersediaan air tanah 60%, 80% 100%, 120% dan 140% KL (Kapasitas Lapang), sedangkan anak petak adalah lima genotipe talas: talas dasheen (ketan dan california), talas eddoe (satoimo dan jepang hijau) dan Xanthosoma (talas kuning). Peubah yang diamati meliputi pertumbuhan, hasil umbi, karakteristik fisiologis seperti laju fotosintesis, transpirasi, konduktansi stomata, ABA, prolin, dan kandungan metabolik sekunder. Tingkat ketersediaan air tanah 120% KL dan 140% KL memberikan pertumbuhan dan hasil terbaik pada semua genotipe talas. Talas satoimo dan jepang hijau menghasilkan bobot umbi segar lebih berat dibandingkan talas ketan, california dan talas kuning pada semua perlakuan tingkat ketersediaan air tanah. Respon pertumbuhan dan produksi talas yang baik pada tingkat ketersediaan air tanah 120% KL dan 140% KL didukung oleh peningkatan laju fotosintesis, transpirasi dan konduktansi stomata lebih tinggi pada tingkat ketersediaan air tanah 120 dan 140% KL dibandingkan dengan perlakuan 60% KL dan 80% KL. Dibandingkan dengan 4 genotipe yang lain, talas jepang hijau pada ketersediaan air tanah 60% KL menghasilkan bobot segar umbi yang tinggi, menunjukkan tanaman dapat beradaptasi pada kondisi kekeringan, hal ini dapat dikaitkan dengan peningkatan efisiensi penggunaan air, kandungan prolin, dan fenol sebagai mekanisme adaptasi pada kondisi kekeringan. Peningkatan kandungan ABA, prolin, MDA, flavonoid, tanin, alkaloid, fenol dan glukomanan pada tingkat ketersediaan air tanah 60% KL dan 80% KL merupakan mekanisme adaptasi talas terhadap ketersediaan air tanah yang rendah (kering).
Keyword: Cultivation, Drought, Stress, Taro, Waterlogging

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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