Judul: Effect of bacteria Micrococcus endophyticus G053 and Bacillus sp. L-12 on the Growth of Potato Cultivar Jala Ipam
Abstrak: Umbi kentang kultivar Jala Ipam sangat cocok untuk kentang goreng. Micrococcus endophyticus G053 dan Bacillus sp. L-12 merupakan bakteri endofit yang mampu meningkatkan pertumbuhan tanaman. Inokulasi bakteri endofit ke planlet kentang kultivar Jala Ipam in vitro diharapkan dapat meningkatkan pertumbuhannya. Penelitian ini bertujuan untuk menganalisis pengaruh Micrococcus endophyticus G053 dan Bacillus sp. L-12 terhadap pertumbuhan kentang kultivar Jala Ipam. Inokulasi bakteri dilakukan pada planlet kentang Jala Ipam yang berumur 2 MST (minggu setelah tanam). Setelah 4 MST, planlet disubkultur untuk mengetahui pengaruh inokulasi endofit pada pertumbuhan planlet hasil subkultur dan keberadaan bakteri endofit. Inokulasi bakteri endofit Micrococcus endophyticus G053 dan Bacillus sp. L-12 meningkatkan pertumbuhan tajuk dan akar planlet kentang. Setelah dua minggu inokulasi, kedua bakteri endofit masih terdapat pada planlet dan dapat tumbuh dengan baik. Subkultur planlet kentang kultivar Jala Ipam menunjukkan bahwa planlet yang sebelumnya diinokulasi dengan kedua bakteri endofit tersebut mempunyai pertumbuhan yang cenderung lebih baik dari pada planlet yang sebelumnya tidak diinokulasi dengan endofit. Hasil ini menunjukkan bahwa bakteri endofit M. endophyticus G053 dan Bacillus sp. L-12 mempunyai pengaruh meningkatkan pertumbuhan planlet kentang kultivar Jala Ipam dan dapat bertahan hidup dengan baik di dalam planlet secara in vitro., The tuber of potato cultivar Jala Ipam is suitable for french fries. Micrococcus endophyticus G053 and Bacillus sp. L-12 are endophytic bacteria that can improve plant growth. The inoculation of endophytic bacteria into the plantlet of potato cv Jala Ipam in vitro is expected to increase its growth. This study aimed to analyze the effect of Micrococcus endophyticus G053 and Bacillus sp. L-12 on the plant growth of potato cv Jala Ipam in vitro. Inoculation of bateria was carried out on the plantlets two weeks after planting (WAP). After 4 WAP, the plantlets were subcultured to determine the effect of endophytic inoculation on the growth of subcultured plantlets and the presence of endophytic bacteria. Inoculation of the endophytic bacterias Micrococcus endophyticus G053 and Bacillus sp. L-12 increased the shoot and root growth of the potato plantlets. After two weeks ofinoculation, both endophytic bacteria were still present in the plantlets and could grow well. The subculture of plantlets of potato cv Jala Ipam showed that the plantlets previously inoculated with endophytic bacteria had better growth than those that were not inoculated. These results indicate that the endophytic bacteria M. endophyticus G053 and Bacillus sp. L-12 have the effect of increasing the growth of plantlets of potato cv Jala Ipam and can survive well in the plantlets in vitro.
Keyword: Bacillus sp. L-12, kentang kultivar Jala Ipam, Micrococcus endophyticus G053, pertumbuhan tanaman

Judul: Growth of Transgenic and Non-transgenic Jala Ipam Potato Inoculated by Endophytic Bacteria Micrococcus endophyticus G053
Abstrak: Tanaman kentang kultivar Jala Ipam transgenik JCL2 dan JCL3 mengekspresikan gen LYZ-C secara konstitutif di dalam sitosol sehingga resisten terhadap bakteri patogen, yaitu Ralstonia solanacearum dan Pectobacterium carotovorum subsp. carotovorum. Gen LYZ-C menyandi lisozim yang merusak dinding sel bakteri dengan cara memotong ikatan β-1,4 di antara N-asetil-D-muramat dengan N-asetil-D-glukosamin pada peptidoglikan sehingga dapat mengakibatkan lisisnya sel bakteri. Bakteri endofit Micrococcus endophyticus G053 dapat meningkatkan pertumbuhan tanaman kentang. Penelitian ini bertujuan untuk mengetahui pertumbuhan plantlet kentang kultivar Jala Ipam transgenik yang mengandung gen LYZ-C dan non-transgenik yang diinokulasi dengan bakteri endofit M. endophyticus G053 secara in vitro. Plantlet kentang kultivar Jala Ipam non-transgenik, JCL2, dan JCL3 yang diinokulasi dengan bakteri endofit M. endophyticus G053 secara in vitro, tidak menunjukkan perbedaan nyata dalam pertumbuhan tinggi batang, jumlah buku, panjang akar, dan jumlah akar. Reisolasi bakteri dari plantlet yang telah diinokulasi sebelumnya dengan M. endophyticus G053 dan dari hasil subkultur plantlet tersebut menunjukkan bahwa M. endophyticus G053 tidak mengalami kematian di plantlet transgenik. Hasil ini mengindikasikan bahwa gen LYZ-C yang terdapat di dalam tanaman kentang kultivar Jala Ipam transgenik JCL2 dan JCL3 yang diekspresikan secara konstitutif di dalam sitosol tidak mempengaruhi pertumbuhan dan perkembangan bakteri endofit M. endophyticus G053. Kata kunci: jumlah akar, jumlah buku, lisozim, panjang akar, tinggi batang, The transgenic potato cultivar Jala Ipam JCL2 and JCL3 expressed the LYZ-C gene constitutively in the cytosol so that it was resistant to pathogenic bacteria Ralstonia solanacearum and Pectobacterium carotovorum subsp. carotovorum. The LYZ-C gene encodes the lysozyme that damages cell walls of the bacteria by cutting the β-1,4 bonds between N-acetyl-D-muramate and N-acetyl-D-glucosamine of peptidoglycan resulting in bacterial cells lysis. Endophytic bacteria Micrococcus endophyticus G053 increases the growth of potato plants. This study aims to determine the growth of transgenic potato cv Jala Ipam plantlets containing the LYZ-C genes and non-transgenic one which were inoculated with endophytic bacteria Micrococcus endophyticus G053 in vitro. Non-transgenic Jala Ipam, JCL2, and JCL3 inoculated with endophytic bacteria M. endophyticus G053 in vitro, did not show significant differences in the growth of stem height, number of nodes, root length, and number of roots. The re-isolation of bacteria from the plantlets previously inoculated with M. endophyticus G053 and the results of the plantlet subcultures showed that M. endophyticus G053 did not die in the transgenic plantlets. These results indicated that the LYZ-C gene contained in the transgenic potato cultivar Jala Ipam, i.e. JCL2 and JCL3 which was expressed constitutively in the cytosol did not affect the growth and development of endophytic bacteria M. endophyticus G053. Keywords: lysozyme, number of nodes, number of roots, root length, stem height
Keyword: lysozyme, number of nodes, number of roots, root length, stem height

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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