Judul: Hubungan antara inhibitor enzim pada Sengon dengan pertumbuhan larva Boktor dalam Artificial Diet
Abstrak: INTRODUCTION. Sengon (Paraserianthes falcataria (L) Nielsen) is widely planted for reforestation programs, especially in establishment of community forest as its timber is utilized for constrction, package box, lighter as well as raw material of pulp and paper. However, there is main problem in sengon plantation, which is boktor (Xystrocera festiva Pascoe) pest attact. In the midgut of boktor larvae it was detected trypsin and α-amylase enzymes activity. Whereas on sengon tree it was reported contains inhibitory substance against trypsin and α-amylase enzymes of boktor larvae. The inhibitory activity was assumed as defense mechanism of sengon tree against the pest attack. In order to clarify the assumption an investigation on the correlation between trypsin and α-amylase inhibitor of sengon with larval growth on an artificial diet is necessary. The experiments aimed at obtaining correlations between the activities of trypsin and α-amylase inhibitors of sengon tree with the growth of boktor larvae, with small (±1,5 cm) and big sizes (±3 cm) on an artificial diet containing respective sengon tree materials. METHODOLOGY. Plant material used was the wood and the bark of sengon trees made into powder by freeze drying. Two provenances were selected, i.e Kediri and Solomon, consisted of two conditions each i.e. healthy and heavily infested. Both small (±1,5 cm) and big sizes (±3 cm) of boktor larvae were put in a big test tubes filled with artificial diet, which contained powder of sengon wood and bark, as their main feed outside their natural habitat. Larvae growth parameters (weight, head diamaters, length and diet consumption) were observed and measured every two weeks. Data on trypsin and α-amylase inhibitors was obtained from biochemical analysis of wood and bark powders using a spectrophotometer. Two kinds of data, larval growth parameters and inhibitors activities, were then correlated using Pearson correlation in Microsoft Excel 2007. RESULTS AND CONCLUSION. Result of the experiments showed that correlation obtained between inhibitor activities of each tissue of each condition and corresponding larvae growth parameters was not all negative, as espected. Out of 64 observations about 35 are positive and about 29 are negatively correlated. In a healthy tree with high trypsin inhibitor activity small size boktor larvae do not prefer attacking. On the contrary similar larvae prefer heavily infested tree with low inhibitor activity. Healthy tree with high α-amylase inhibitor activity will be saved from big size boktor larvae preferences. The opposite accurs on heavily infested tree with low inhibitor activity, which is preferred by big size larvae. In order to obtain negative correlation for trypsin inhibitor it was suggested to do similar experiments using small size larvae, while for α-amylase inhibitor it was suggested using big size larvae.
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Judul: Pengaruh Provenan Sengon Terhadap Perkembangan Larva Boktor (Xystrocera Festiva Thoms) Dalam Makanan Buatan (Artificial Diet)
Abstrak: Problem which is most commonly encountered in the management of sengon plantation forest, at present was the attack by stem borer insect Xystrocera festiva Thoms, a pest which is more often referred to as boktor, uter-uter, wowolan, and engkes-engkes. Up to now, the effective and efficient specific control for boktor pest, has not been discovered yet. One method which had ever been practiced was slicing the sengon bark and discarding the boktor larvae existing inside the tree. However, this practice will damage the physiological process of sengon trees, and this will in turn reduce the quality and price of sengon wood. One of the cause which makes the control of boktor has not been fully successful is the lack of knowledge concerning this insect, particularly in its larval stadium (the damaging phase), when this insect larvae live under the bark, which makes the study of biology and physiology of the insect difficult. For overcoming this phenomenon, a laboratory research was conducted where the boktor insects were reproduced and observed while being raised using artificial diet. This research was useful for obtaining information on the behavior and life cycle of boktor. The objectives of this research were learning the effects of provenance, tree health condition (sick or healthy condition of trees) and artificial diet on the growth of boktor larvae, and seeking the appropriate composition of artificial diet for boktor larvae. Materials used in this research were sengon wood powder from Kediri and Subang provenance with two kinds of tree condition (sick and healthy trees) while each of them had undergone freeze drying process, yeast extract, streptomycin, sucrose, agar, aquadest, vitamin C, vitamin B, benzoate, NaCl, dolomite, olive oil, and small sized boktor larvae (1.4 – 2.4 cm). The parameters observed and measured were larvae weight, weight of consumed food by the boktor larvae, larvae length, and diameter of boktor larvae head. Observation and measurements were conducted each week for 8 weeks, while conducting also food change. Results of analysis of variance showed that the provenance factor exhibited the greatest and significant effect on larvae growth (larvae length, diameter of larvae head) and amount of food consumed by the boktor larvae. On the other hand, factor of tree condition did not create significant effect on all parameters for 7 weeks. Factor of tree condition was seen to have effect on week 8. Patterns of average growth of larvae weight and length, for all treatments showed significant decrease in week-5 and 6. This phenomenon occurred because at week 5 and 6, many larvae underwent ecdysis (molting). Results of Duncan test showed that Subang provenance gave the best effect. The best growth of boktor larvae, namely those of Subang provenance had larvae length increment of 2.53 mm and larvae head diameter increment of 0.166 mm. Feeding behavior of boktor larvae during the laboratory research, using artificial diet, was similar with that in the field. Keywords: sengon, artificial diet, boktor
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Judul: Persamaan Gelombang Permukaan Dalam Sistem Hamiltonian
Abstrak: Fluida adalah suatu zat yang bentuknya dapat berubah secara kontinu akibat gaya geser. Dua bentuk fluida yang dikenal adalah fluida yang berbentuk cairan dan gas. Dalam tulisan ini akan dibahas fluida yang berbentuk cairan. Persamaan yang memodelkan fenomena gelombang fluida di antaranya adalah sistem Hamiltonian. Persamaan ini berasumsi babwa fluida dalam keadaan ideal di mana fluida tak mampu mampat (inkompresibel), fluida tak rotasional (irrotasional).
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