Judul: Increasing the growth of mangosteen (Garcinia mangostana) seedlings with growing media optimation
Abstrak: Mangosteen is slowly growth trees that caused by root system development. Mangosteen root system has limited number of lateral roots and easily disturbed by unfavorable medium environmental conditions such as poor aeration, water availability, and nutrient content. The objective of this study was to enhance the growth of mangosteen seedlings by modifying media properties. The experiment was conducted in the Plastic house at Centre for Tropical Fruit Studies (CETROFS) Bogor Agricultural University, Tajur from January 2009 until May 2011. The study consisted of five experiments. The first experiment conducted to study the morphological and physiological characteristics of mangosteen seedlings that cultivate in drought conditions. Experiment arranged in a completely randomized block design with three replications. The results shown that an increasing the level of drought stress was decreased canopy and root growth include plant height, leaf area, root length, shoot and root dry weight and also root volume. Increasing the level of drought stress also led to significantly increased proline content. The second experiment was conducted to obtain the porosity of the media from various sources. The result shown that the lowest porosity in media was 53.48% and the highest was 69.63%, thus this research obtained four porosity ranges e.i.: 51-55%, 56-60%, 61-65% and 66-70%. These criteria then applied as the basis of the experimental treatments for the third study. The third experiment was conducted to analyses the growth of mangosteen seedlings at different water availability and porosity of the media. The result shown that watering intervals 6 day + water retaining polymer (WRP) at 61-65% porosity media drive the availability of optimal water and air. It caused an optimal rate of photosynthesis, stomata conductivity and the highest water potential of leaf tissue. The fourth experiment was conducted to study the growth of mangosteen seedlings at different method of fertilizer application and porosity of the media. The result shown that fertilizer application by fertigation in 61-65% porosity media produced the highest growth of root length, root dry weight, shoot dry weight and total dry weight. Nutrient uptake of N in the leaf by fertigation applications was support shoot and root growth higher than the application of granular fertilizers and slow release fertilizer. The fifth experiment was conducted to study mangosteen plant growth in two types of pots containers in various media porosity. Results shown that the use of woven bamboo pots obtained shoot and root growth higher than the polybag. As the results from previous experiments, the porosity of 61-65% seems to consistently produce the highest shoot and root growth.
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Judul: Engineering technology of micrografting and microcutting in mangosteen (Garcinia mangostana).
Abstrak: The purpose of this study was to assemble propagation technology in mangosteen plant using micrografting and microcutting. This study consisted of four experimental steps, 1) in vitro bud induction technology development from bud explants of mangosteen seedling shoot, 2) physiology and anatomy studies of micrografting in mangosteen, 3) in vitro medium manipulation on mangosteen microcutting; 4) optimization of microcutting acclimatization on mangosteen with sterile porous medium technique (MSP) / in vitro soil-less propagation (IVS). The results of experiment I showed that the best medium for shoot induction phase was MS + BA 4,0 + TDZ 0,2 mg/l, MS + BA 8,0 BA + TDZ 0,2 or MS + BA 4,0 mg /l. Medium multiplication could not obtain shoot multiplication, only addition of nodes and elongation of shoots. The best medium for shoot elongation was medium MS + BA 1 mg/l + KIN 1 mg/l. Experiment II showed that the rootstock derived from a single intact seed germination was better success than other treatments in almost all the observed variables, such as flush shoot that was better success than dormant shoot. There are several factors that determine the success of micrografting, which is width of meristem encounter between the rootstock and scion, the equal cell growth rate between rootstock and scion cells, as well as the similarity in size and structural congeniality between rootstock and scion. The results of anatomical tissue observation (4 months after micrografting) indicated that there was a good graft union on micrografting. Roostsock and scion xylem tissue were fused perfectly. Experiment III results showed that the concentration of 25% MS medium concentration on various substrates with or without the addition of IBA might cause 50-80% of microcutting rooted with the root length between 1,8 to 4,38 cm. Experiment IV results showed that microcutting carried out using MSP technique could grow roots, even at the microcutting that were untreated with root growth stimulating substances. Microcutting that planted using a MSP technique with IBA and Rootone-F treatments at varied concentrations could cause mangosteen microcutting 100% rooted with the root length from 3,44 to 6,88 cm.
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Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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