Judul: Respon Pohon Gaharu dan Reaksi Hipersensitif Tembakau Terhadap Elisitor Acremonium spp. dan Fusarium spp. Asal Gaharu
Abstrak: This research was carried out to investigate the effectiveness of Acremonium spp. and Fusarium spp. biomass in inducing agarwood formation and the effectiveness of the cell wall elicitor (CWE), conidia elicitor (CE), and crude filtrate elicitor (CFE) of Acremonium spp. (IPBCC 07.525, 07.526, 07.566) and Fusarium spp. (IPBCC 09.568, 09.569, 09.570, 09.571) in inducing the hypersensitivity response of tobacco leaves. Biomass of Acremonium spp. and Fusarium spp. were grown on PDA medium for 14 days and used as inoculant on Gyrinops verstegii branch. All Elicitors were derived from the 12 days Acremonium spp. and Fusarium spp. culture in PDB medium. Agarwood formation was determined by score system (0-10) and classified into three categories based on the average score of each three respondents observation. Acremonium sp. IPBCC 07.526, 07.566, and Fusarium sp. IPBCC 09.571 induced agarwood formation with scores 2,67, 2,89, and 2,78, respectively at 14 days after inoculation (dai). These agarwood were in category 2. Hypersensitive reaction of tobacco leaves (Nicotiana tabacum cv. Gewol) caused by elicitors of all isolates were shown in the necrosis spot with score range of 0,33-1,33 from score system 0-3. All elicitors had the different pathogenicity. The ability of fungi to induce agarwood formation were comparable to hypersensitivity reaction caused by those elicitors. The correlation of agarwood formation by Acremonium sp. IPBCC 07.526, 07.566, Fusarium sp. 09.571 with hypersensitive reaction of their EDS, EK, EFK was positive, high, and significant with correlation coefficient (r) values respectively were 0,831, 0,884, 0,884.
Keyword: 

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.
Keyword: 

Judul: Penyelesaian Masalah Rotasi Aliran Fluida Kental Von Karman Menggunakan Metode Homotopi
Abstrak: Von Karman equation is an equation that describes fluid viscous flow induced by infinite disk rotation. By assuming steady flow and laminar, viscous incompressible fluid flow is represented in Von Karman equation by an angular velocity and the vertical direction velocity as the independent variables. Von Karman equation is a nonlinear problem that is solved using the homotopy method. The use of homotopy method is done by defining an homotopy function that requires auxiliary parameters to control the convergent region of the solution. The solution is a recursive formula with given initial conditions. Using software based-functional shows that velocity components converge to a value.
Keyword: