Judul: Potensi dan Keanekaragaman Fungi Mikoriza Arbuskula (FMA) di Ekosisitem Hutan Karet Alam, Jambi
Abstrak: Mikoriza adalah bentuk simbiosis mutualisme antara fungi dengan sistem perakaran tanaman tingkat tinggi. Mikoriza memiliki banyak manfaat bagi tanaman inang, salah satunya meningkatkan penyerapan unsur hara seperti fosfor. Penelitian mengenai keanekaragaman Fungi Mikoriza Arbuskula (FMA) di berbagai tipe ekosistem sudah banyak dilakukan, namun penelitian di ekosistem karet alam masih terbatas. Penelitian ini dilakukan untuk menganalisis keanekaragaman dan potensi FMA di ekosistem karet alam Harapan dan Bukit Dua Belas, Jambi. Perhitungan potensi propagul menggunakan metode Most Probable Number (MPN). Pengamatan Kolonisasi FMA pada akar Purarea javanica menggunakan teknik pewarnaan akar sedangkan isolasi spora menggunakan metode tuang basah. Genus FMA yang ditemukan di kedua lokasi adalah Glomus dan Acaulospora. Jumlah spora dan potensi FMA lebih tinggi di ekosistem karet alam Harapan, karena memiliki kandungan fosfor di dalam tanah lebih sedikit dibandingkan ekosistem karet alam Bukit Dua Belas. Hasil pengamatan menunjukan bahwa jumlah kepadatan spora tidak berpengaruh terhadap jumlah kolonisasi akar.
Keyword: fungi mikoriza arbuskula, kolonisasi, potensi propagul

Judul: Potensi Fungi Mikoriza Arbuskula (FMA) di Ekosistem Tanaman Karet, Jambi
Abstrak: Mikoriza adalah suatu hubungan simbiosis mutualisme antara fungi dengan perakaran tumbuhan. Fungi mikoriza arbuskula merupakan fungi yang penyebarannya sangat luas di alam, tetapi penelitian FMA di ekosistem tanaman karet belum pernah dilakukan. Penelitian ini perlu dilakukan untuk mengetahui keanekaragaman dan potensi FMA di ekosistem tanaman karet. Pengamatan kolonisasi FMA pada akar Pueraria javanica menggunakan teknik pewarnaan akar sedangkan isolasi spora dengan menggunakan metode tuang basah. Penghitungan potensi propagul digunakan metode Most Probable Number (MPN). Hasil pengamatan menunjukkan bahwa jumlah kepadatan spora tidak berpengaruh terhadap jumlah kolonisasi akar. Dalam penelitian ini ditemukan 3 genus spora yaitu Glomus sp., Acaulospora sp., dan Gigaspora sp. Genus Glomus merupakan genus yang paling dominan karena terdapat pada setiap lokasi. Jumlah propagul di ekosistem tanaman karet daerah Harapan lebih banyak dibandingkan dengan daerah Bukit Dua Belas.
Keyword: fungi mikoriza arbuskula, kolonisasi, potensi propagul

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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