Judul: Induksi Pembelahan Sporofitik Mikrospora Kedelai Melalui Kultur Antera Pada Sistem Media Dua Lapis
Abstrak: Pemuliaan kedelai masih dilakukan secara konvensional, yaitu dengan cara menyilangkan antar varietas yang dilanjutkan dengan proses seleksi untuk menghasilkan varietas baru. Proses ini membutuhkan waktu yang lama, khususnya dalam proses seleksi untuk memperoleh galur-galur yang stabil secara genetik, yaitu 7-8 generasi. Untuk itu diperlukan introduksi teknik untuk mempercepat stabilitas genetik dari suatu hasil persilangan. Salah satu alternatif untuk mempercepat stabilitas genetik adalah teknologi haploid melalui induksi androgenesis untuk embriogenesis.
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Judul: Perkembangan Mikrospora dan Induksi Pembelahan Sporofitik pada Kultur Antera Kelapa Sawit (Elaeis guineensis Jacq.)
Abstrak: Pengembangan varietas hibrida kelapa sawit membutuhkan ketersediaan galur-galur murni untuk dijadikan tetua. Teknologi haploid dapat dikembangkan untuk menghasilkan galur-galur murni (tanaman haploid ganda) secara efisien hanya dalam 1-2 generasi. Penelitian ini bertujuan menginduksi pembelahan sporofitik pada kultur antera dalam media dua lapis yang merupakan langkah awal pengembangan kultur haploid pada kelapa sawit. Pangkal spikelet dari spikelet yang terdapat pada pangkal malai dari malai jantan yang memiliki ¼ bagian pangkal malai berwarna kuning dan ¾ bagian ujung malai berwarna coklat mengandung mikrospora tahap uninukleat akhir. Sedangkan ujung spikelet dari spikelet yang terdapat pada ujung malai dari malai jantan berwarna coklat dan sebagian seludang telah terbuka mengandung mikrospora tahap biselular awal. Mikrospora tahap uninukleat akhir yang dikulturkan pada media standar embriogenesis somatik kelapa sawit, memperlihatkan perkembangan gametofitik sampai tahap biselular pada umur 6 sampai 10 hari setelah kultur (HSK). Pemberian cekaman suhu tinggi (32-33ºC) dalam periode 0, 1, 3 dan 7 hari yang dikombinasikan dengan perlakuan sumber karbon berupa sukrosa, maltosa ataupun manitol tidak dapat menginduksi pembelahan sporofitik dalam antera pada kutur in vitro. Namun perlakuan cekaman suhu tinggi selama satu hari yang dikombinasikan dengan sumber karbon maltosa 40 g/l dapat mempertahankan persentase mikrospora hidup sebesar 74.5% sampai 28 HSK.
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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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