Judul: Pengaruh asam salisilat terhadap sifat kayu gaharu (Aquilaria crassna)
Abstrak: Salicylic acid is one of secondau signal molecule for the formation of secondary metabolites, that has a role as defense substance. The role of salicylic acid on the formation of agarwood is not yet known. The indicator of the agar formation is the modification of the wood characteristic such as wood discolouration.Wood discolouration may occur due to terpenoid accumulation. This research was carried out to determine the role of salicylic acid on the modification of wood characteristic interm of discolouration and te~penoida ccumulation of A. oassna. The bark and cambial layers of branches of 8 years A. crassna tree were peeled off about 2 cm long, then smeared with salicylic acid at 100mM (SA loo), 200mM (SA 200), 3001nM (SA 300), 400mM (SA 400), 700mM (SA 700) and IOOOmM (SA 1000). The level of wood colour intensity and the area of colour formation, accu~nulation of terpenoid (histochemical and Lieberman-Burchard analyses) and fiagrance level was observed at 5, 10, 25 and 50 days after application of salicylic acid (daa). The application of salicylic acid caused wood discolouration from white to brownish white, physiological symptoms such as chlorosis (SA 400 at 50 daa and SA 700 at 5 daa), wood brittleness and death of some branches (SA 700 at 25 daa and SA 1000 at 5 daa). Histochemically, the accumulation of terpenoid was found in parenchyma rays, included phloem, xylem vessel and pith of treated branches with SA 100, SA 200, SA 300 and SA 400. For those treated with SA 700 and SA 1000, terpenoid was found only in parenchyma rays and xyleni vessel. Accutnulation of lipid was found in parenchyma mys, included phloem and xylenl vessel of all treated branches. Whereas the accu~nulation of starch was found in parenchyma rays and included phloem on all treated branches at 5-10 daa. Yellowgreen the Liebennan-Burchard analysis indicated that terpenoid in the forin of sterol was formed in the heated wood. Salicylic acid can not induce fiagrance formation.
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Judul: Karakterisasi interaksi antara tanaman aquilaria microcarpa baill dengan fusarium solani dalam pembentukan gaharu
Abstrak: Aquilaria microcarpa is native to Indonesia and has been identified and promoted as potential tree species to yield high quality agarwood (gaharu). Individual trees of this species, both in its natural habitat and plantation, do not always yield agarwood due to many influencing factors. It is estimated that only 10% trees would be able to yield the resin. A clear mechanism of agarwood formation is unknown and there is a lack of information on underlying causes and triggers of the formation due to natural complexity and uncertainty. However, natural defense mechanisms through a series of pathogenesis are presumed as naturally observed in other resin producing tree species. Research on the characterization of host-pathogen interaction in gaharu formation was carried out based on the above mentioned problems with the following specific objectives, namely: i). to identify morphological characters of A. microcarpa trees interacting with F. solani sp, ii). to determine wood anatomical characters of A. microcarpa interacting with F. solani, and iii) to verify the genotypes of A. microcarpa seedlings and trees interacting with F.solani based on microsatellites. Results on tree morphological analysis showed that two out of 17 morphological characters (descriptor), namely tree height (m) and branching angles (0), showed significant differences between inoculated and non-inoculated individuals. In addition, microscopic observations on wood anatomical characters of A. microcarpa revealed that inoculated plants clearly deposited golden-brown colored resin in pores and canticles with a distinct scent. Further verification using GC MS on the sediment deposits identified common compounds as reported in many previous research on agarwood, namely: baimuxinal, elemol, 3-phenyl-2-butanone and chromone-3-one. On the other hand, tests on the viulence degrees of F. solani showed that one out of 4 strains, i.e. F.solani FORDA 512, showed the highest level of virulence and was significantly different with other F.solani, especially if inoculated on seedlings A60, A68 and B30. Two microsatellite loci of A. crassna, i.e. 6Pa18 and 71Pa17, were successfully transferable to A. microcarpa and could be used to characterize the genotypes of Fusarium-treated seedlings (n=40), inoculated trees (n=20) and non-inoculated trees (n=20). There were differences in terms of genetic structures between tree population and seedling population. Further sequence analysis on the microsatellite fragments on the most virulent F.solani FORDA 512- inoculated seedlings indicated genotype dependant responses for both seedling and tree stages. In addition, Sequence based cladogram showed that inoculated seedlings were closely placed with inoculated trees indicating certain genetic roles in the agarwood formation. In conclusion, tree morphological (i.e. height growth and branch habit) as well as genetic and genomic characters were clearly observed and useful to provide early information on gaharu formation. It is also supported by the wood anatomy analysis showing the presence of gaharu resin.
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Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model