Judul: Studi iradiasi sinar gamma pada kultur kalus nodular manggis untuk meningkatkan keragaman genetik dan morfologi regeneran
Abstrak: Tanaman manggis termasuk tanaman apomik obligat dan karena itu keragaman genetiknya sempit. Peningkatan keragaman genetik ini dapat dilakukan dengan induksi mutasi dengan sinar gamma. Tujuan dari penelitian ini adalah mengembangkan metode regenerasi tanaman manggis secara in vitro dan meningkatkan keragaman genetik manggis melalui induksi mutasi dengan iradiasi pada kultur kalus nodular. Penelitian terdiri dari empat rangkaian percobaan, yaitu : (1) Studi regenerasi tanaman manggis in vitro, (2) Induksi mutasi dengan sinar gamma pada kultur kalus nodular dan uji keragaman dari regeneran, (3) Studi anatomi daun mutan putatif manggis in vitro, (4) Uji keragaman genetik mutan putatif dengan marka RAPD. Percobaan dilakukan di Laboratorium Kultur Jaringan dan Molekuler Pusat Kajian Buah-buahan Tropika (PKBT) IPB, sejak Juli 2002 sampai dengan Desember 2005.
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Judul: Analisis keragaman genetik manggis (Garcinia mangostana L.) hasil iradiasi sinar gamma berdasarkan morfologi, anatomi, dan penanda ISSR
Abstrak: Manggis merupakan buah asli indonesia yang mempunyai prospek sangat cerah untuk dikembangkan. Tanaman manggis berkembangbiak secara aseksual melalui embrio adventif, sehingga keragaman genetiknya rendah dan perbaikan sifat melalui persilangan konvensional tidak mungkin dilakukan. Salah satu cara yang telah lazim digunakan untuk meningkatkan keragaman genetik manggis adalah dengan induksi mutasi dengan menggunakan iradiasi sinar gamma. Tujuan dari penelitian ini adalah untuk: (1) Mendapatkan manggis dengan keragaman genetik lebih tinggi melalui iradiasi dengan sinar gamma, (2) Mendapatkan metode iradiasi yang paling efektif pada manggis dalam rangka meningkatkan keragaman genetik. Materi yang digunakan dalam penelitian ini berasal dari biji manggis asal Kampung Cengal, Desa Karacak, Kecamatan Leuwiliang, Kabupaten Bogor. Pengamatan dilakukan terhadap karakter morfologi, anatomi, dan DNA dengan menggunakan marka ISSR. Pengamatan morfologi meliputi waktu dan jumlah munculnya tunas, tinggi tanaman, diameter daun, jumlah daun, panjang dan lebar daun. Pengamatan anatomi dilakukan terhadap irisan paradermal meliputi jumlah stomata, jumlah epidermis, indek stomata dan kerapatan stomata, dan irisan transfersal meliputi tebal kutikula, epidermis, parenkim palisade, bunga karang dan tebal daun. Pengamatan molekuler dilakukan berdasarkan pita-pita yang muncul.
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Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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