Judul: Studi Pembungaan dan Perkembangan Buah Serta Viabilitas Polen Pohon Gaharu (Gyrinops versteegii)
Abstrak: Gyrinops versteegii is a potential agarwood tree which should be developed and cultivated. In purpose of widely cultivated, information of fruit and flower development is needed. The aim of this research was to study fruit and flower development and the viability of pollen of agarwood tree. Morphology of flower and fruit studies were carried out in the field, while the anatomical observation and viability of pollen were carried out in laboratory. The result showed that generative bud generally had 1-15 flowers. The flower belongs to a perfect flower, with a racemose inflorescense. Amount of stamen, petal and sepal are varied within 3-8. Sepal and petal arranged in radial form. The colour of flower is green-yellowish. Length of flower 10-18 mm. Flower bud grew to form full flower about 13-27 days. After 7-20 days after anthesis flower formed a fruit. Fruit became yellowish in the fifth week after anthesis. Percentage of fallen flower was about 88,8%. The shape of fruit is circular, green, and when ripening the colour of rind is orange. The fruits have started ripening at 8-11 week after anthesis. The seed is 2 generally in each fruit. Percentage of fallen fruit was about 61,9%. Pollen viability were tested by stainning technique with eithers stain. Pollen viability was determined by either anilin blue 1% or I2KI 1% staining technique. Viability was depended on the stainer used. Viability with I2KI 1% (96,4% - 98,9%) was higher than those with anilin blue 1% (88,3% - 97,7%).
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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: Invers Drazin dari Matriks Toeplitz Singular
Abstrak: Matriks Toeplitz adalah matriks yang setiap unsur pada diagonal utama bernilai sama dan setiap unsur pada subdiagonal yang bersesuaian dengan diagonal utama juga bernilai sama. Matriks singular adalah matriks yang tidak bisa ditentukan inversnya. Akan tetapi, dapat diupayakan untuk ditentukan inversnya menggunakan invers matriks yang diperumum. Invers Drazin merupakan salah satu jenis invers matriks yang diperumum. Pada karya ilmiah ini ditentukan invers Drazin dari matriks Toeplitz singular dengan menggunakan metode Leverrier Faddeev. Kemudian, ditentukan invers Drazin dari matriks Toeplitz singular yang direpresentasikan sebagai penjumlahan segitiga bawah dan segitiga atas matriks Toeplitz berdasar pada teorema Gohberg dan Semencul., Toeplitz matrix is a matrix in with element on the main diagonal has the same value and on the subdiagonal corresponding to the main diagonal also has the same value. Singular matrix is a matrix that has no inverse. However, it can be attempted to determine the inverse using a generalized inverse matrix. Inverse Drazin is a type of generalized matrix inverse. This paper discussed the inverse Drazin for a singular Toeplitz matrix using the Leverrier Faddeev method. Then, the Drazin inverse of the singular Toeplitz matrix which is represented as a sum of products of lower and upper triangular Toeplitz matrix based on Gohberg and Semencul theorem.
Keyword: inverse Drazine, singular Toeplitz matrix