Judul: Induction of genetic variability through gamma rays irradiation on embryogenic callus derived protoplast of tangerine cv. siam
Abstrak: Tangerine cv. Siam has sweet flavor, easily peeled skin, soft and juicy flesh. However, it has relatively many seeds (15-20 seeds per fruit), so it can not be competed with citrus from other countries. Fruit quality improvement of citrus has been the subject of citrus breeding program. The first step of breeding program is to increase variability, in order to efficient the selection process. Callus derived protoplast which sub cultured several years has a level of variability. The objective of this research was to increase variation of Tangerine cv. Siam through gamma irradiation on callus derived protoplast. Callus was exposed to gamma irradiation at 0, 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 Gray. Observation on the growth of callus four weeks after irradiation showed variation on morphology and weight of callus. At low doses (10-50 Gray) callus growth were not inhibited, but at high doses (60-100 Gray) callus growth were inhibited. The result of radio sensitivity dose analyzed by Curve Expert 1.4 software was 53.25 Gray. Callus regeneration ability (somatic embryo maturation and germination) were very diverse between irradiated and non-irradiated callus. Gamma irradiation affects the formation of somatic embryos. After four weeks on MW (Morel-Wetmore) medium containing 0.5 mg/l ABA, 50 Gray callus produced more somatic embryos than other doses. After four weeks on MW medium containing 0.5 mg/l GA3, only 75.9% somatic embryos from 50 Gray callus could germinate, less than other doses. All somatic embryos from non-irradiated callus could germinate. The germination of somatic embryos produced 72 regenerated plantlets. Dendogram based on morphological observations of 0 Gray regenerated plantlets showed 40% variability, while of 50 Gray were 47% and that of 60 Gray were 46%. Ten regenerated plantlets were chosen based on its variability and growth (P-2, P-8, 50-4, 50-6, 50-15, 50-24, 60-8, 60-10, 60-11 and 60-23). Dendogram based on morphological observation between 10 regenerated plantlets showed 30% variation. Molecular analysis of the 10 regenerated plantlets using three ISSR primers (ISSR-1, ISSR-2 and ISSR-4) produced 17 bands with nine polymorphic bands (52.94%). Dendogram based on molecular analysis between 10 regenerated plantlets and wild type shoots showed 22% genetic variation. In vitro and ex vitro grafting between regenerated plantlets and JC rootstock could accelerate optimal growth of plantlets. Application of ex vitro grafting was more efficient than in vitro grafting. Ex vitro grafting did not need acclimatization stage, where as in vitro grafting still need acclimatization stage before transfer to soil.
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Judul: Study Regeneration of Tengerine Citrus Batu 55 (Citrus reticulata) Through Somatic Embryogenesis Path Way
Abstrak: The global world market of citrus fruit that is consumed in fresh form to the current needs to fill a category of fruit that do not have seeds, easy to peel and has an attractive color (pigmented). Tangerine citrus Batu 55 is one of the mainstay of fresh fruit horticulture. Tangerine citrus Batu 55 has superior character who naturally have had so distinguished by citrus Siam but the characters are not as good as tangerine imports. Somatic embryogenesis is an important tool for supplying new varieties to be used cultivar genetic improvement programs in citrus, this technology has been extensively used and has many important implications. The objective of this research is to produce somatic embryos of Tangerine citrus Batu 55 from nucellar embryo. The research comprised: embryogenic callus induction, callus prolifertation, maturation of somatic embryo, germination of somatic embryo, shoot multiplication, roots induction, chromosome counting, acclimatization and grafting. The results showed that the medium of Murashige & Tucker + 3 mg/l BAP + 1 mg/l 2,4-D + 500 mg /l malt extract increased the percentage of the callus formation up to 40% after 4 weeks with total number of pre-embryos (PEM ) 31.0. The medium proliferation used was MS with the addition of vitamin Morell & Wetmore (MW) +3 mg/l BAP+300 mg/l casein hydrolisat. These medium improved callus diameter up to 2.3 mm after 4 weeks cultured. Maturation of embryos was obtained by transferring globular structure in the medium MW + 2.5 mg/l ABA + 500 mg/l malt extract. These medium increased the percentage of mature somatic embryo up to 98% after 4 weeks cultured. Somatic embryos up to 84% germinated when the cotyledons grown in the medium MW + 2.5 mg/l GA3. The shoot multiplication containing MW medium + 7 mg/l biotin +500 mg/l malt extract was able to produce the highest percentage of shoot multiplication up to 86 %. The root induction containing MS medium + 3 mg/l IBA was able to produce the highest percentage of root induction up to 86%. Acclimatization of plantlets with roots increased survival rate up to 90% after 5 weeks acclimatization.
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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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