Judul: Aspek biologi dan genetika pada sistem reproduksi mindi (Melia azedarach Linn.)
Abstrak: The study was aimed to determine biological and genetical aspects of reproductive system of mindi in relation to securing high quality of seeds. The study was conducted at four sites in West Java for the periods of 2009-2011. Direct observation over the trees (n=5-20 trees) were conducted on the periods of flowering and fruiting as well as floral morphology. Representative buds, flowers and fruits were sampled for microscopic dissection and reproductive study. The level of genetic diversities of maintained parental and produced offspring were evaluated either phenotipically or genotipically. Molecular characters were determined by using microsatellite markers. The genotipe deviation was evaluated based on Hardy-Weinberg and inbreeding structures. The observation revealed that floral initiation had proceeded for more than three months and the highest percentage of floral initiation occured in September. Reproductive cycle was proceeded for 5-6 months within the year, first observation commenced from generative buds to flower burst in September-October. Fruits reached maturity in January-February that took about 2-3 months after flower burst. The flower was hermaphroditic with position of anther was closed to stigma that selfing might be happened. Stigma receptivity lasted from 08.00 am to 11.00 am, rate of receptif was 66% in average, at 12.00 the receptivity was decreased to 40% and pollen viability was fluctuated from 4,89%-7,03% observed from 07.00 am-11.00 am. Controlled pollination exposed that mindi could be able to do both of cross- and self-pollination with the percentage of fruit set ranged of 70-77% and 42-57%, respectively. The genetic variation of mother trees and progenies for all loci and population were at range of 0,49-0,51 and 0,288-0,426, respectively. Genotipe deviation in progeny was detected at a small part of loci in two population with an average fixation index of -0,0680 and thus inbreeding might have been occured in a mating system of mindi in a low level. Assortative mating was detected in a very low degree. Three characters of seedling growth i.e length of bud, length of petiole and ratio of petiole to leaf length, might have to be used as keys to effective indicator for seedling selection.
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Judul: Keragaman Genetik dan Sistem Perkawinan pada Tegakan Benih Mindi (Melia azedarach Linn.) di Wanayasa, Purwakarta
Abstrak: Mindi is a fast growing species belonging to family Meliaceae which is potential to be developed in community forest. Efforts to increase productivity of mindi seed stand require basic knowledge on genetic diversity and mating system. The sexual flower character of mindi is of hermaphrodite type raising a question about the mating system of Mindi. Genetic diversity and mating system characteristics of mindi can be analyzed by microsatellite. This study was aimed to i) cross-amplify microsatellite primers of Mahogany (Swietenia spp) and Neem (Azadirachta indica) in Mindi, ii) estimate genetic variation of mother trees and their offspring and iii) characterize the parameters of mating system of a mindi seed stand. The samples for DNA analysis were 10 mother trees and their respective offspring (n=5). Specific primers Ai-05 and Ai-34 from Neem and SM45 from Mahogany was successfully amplified in Mindi. Data analysis using POPgene version 1.31 showed the average values of genetic diversity of He=0.565 in the seed stand population. Mating system analysis analyzed by multilocus mating system program showed outcrossing values of tm= ts = 1.00 based on the method of expected maximum (EM). These findings indicated that Mindi in the seed stand Wanayasa is predominantly outcrosser. Basic information on the mating system characteristics of Mindi may be used for effective management for increasing the productivity of seed stands.
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Judul: Pemanasan Sekunder Reaksi Fusi Plasma dengan Menggunakan Radio Frequency
Abstrak: Plasma merupakan bentuk ke-empat dari materi setelah padat, cair dan gas yang terbentuk dari proses ionisasi gas. Plasma dapat digunakan dalam reaksi fusi, yaitu reaksi penggabungan dua inti atom ringan menjadi inti atom yang lebih berat sambil melepaskan energi. Untuk mendapatkan energi dari reaksi fusi, inti yang akan direaksikan harus dipanaskan pada temperatur yang sangat ekstrem tingginya. Salah satu cara agar dapat mencapai kondisi ini adalah memberikan pemanasan tambahan atau pemanasan sekunder kepada plasma dalam reaksi fusi tersebut. Nilai daya serap rata-rata ion Deuterium yang sesuai dengan selang nilai daya dari data ITER adalah daya yang menggunakan frekuensi 50 MHz sampai dengan 60 MHz. Dengan menggunakan frekuensi 60 Hz diperoleh nilai daya rata-rata yang diserap sebesar 1,235.10-12 W.
Keyword: gelombang radio, pemanasan sekunder, plasma, reaksi fusi