Judul: Ekspresi Gen Aminocyclopropane Carboxylic Synthase pada Klon Tanaman Karet Akibat Pemberian Etefon
Abstrak: Stimulant treatment using etephon is one way to increase production of natural rubber. Etephon will affect gene expression of Hb ACS, a gene coding for the enzyme. The research aimed to isolate and compare the gene expression patterns of Hb ACS due to the provision 2.5% etephon on the leaves and bark of rubber tree clones PB 217, GT 1 and PB 260. The samples that already treated with 2.5% etephon were collected at the time 0 until 8 hours, then the RNA were isolated and analyzed of gene expression by RT-PCR. Etephon treatment capable to affects the expression of Hb ACS-F2 and Hb ACS-E4 on PB 217 clone at the maximum observed in the leaves between 2-4 hours and 6-8 hours on the bark. Hb ACS-D10 expression in the leaves was observed at the 2nd and 6th hours, while in the bark was observed on the 8th hour. Hb ACS-F2 and Hb ACS-E4 expression on GT 1 clone were observed at the maximum on the leaves after 4-8 hours, while in the bark the expression of Hb ACS-F2 was observed more uniform until 8 hour and the Hb ACS-E4 fragment was not expressed. The Hb ACS-F2 expression on PB 260 clone maximum observed on leaves at 0, 4th, and 8th hours, while in the bark was observed after 2 hours maximum. The Hb ACS-E4 expression on PB 260 clone was observed more uniformly on the leaves until 8th hour, while in the bark maximum observed at 0 hours after application etephon. The Hb ACS-D10 expression on GT 1 and PB 260 clones were not observed.
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Judul: Response of physiological characters and latex production to ethylene stimulation on several rubber tree clones
Abstrak: Penelitian bertujuan untuk mengetahui variasi musiman karakter fisiologi tanaman karet akibat pemberian etepon, dan hubungan antar karakter fisiologi dengan produksi lateks. Penelitian dilaksanakan di Bogor, Jawa Barat (250 m dpl) mulai September 1997 hingga Desember 1998. Percobaan dalam dua faktor perlakuan, yaitu delapan klon karet (AVROS 2037, BPM 24, PR 261, RRIM 712, GT 1, BPM 1, PR 228, dan LCB 1320) dan tiga sistem eksploitasi (& = '/z S d/2, El = '/z S d/3.ET2.5%, E2 = '/z S d/3.ETS.O%). Peubah yang diamati adalah produksi lateks, indeks penyumbatan, kadar karet kering, %-KAS, pH lateks, kadar sukrosa, kadar fosfat anorganik, kadar tiol, aktivitas SOD, produksi etilen, kadar ACC, aktivitas ACC-oksidase; dan protein dalam fraksi serum-C dan lutoid Hasil penelitian menunjukkan bahwa perlakuan stimulasi meningkatkan produksi lateks pada empat klon (PR 261, BPM 24, PR 228, dan AVROS 2037).
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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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