Judul: Seleksi Kekeringan pada Beberapa Varietas Batang Bawah Jeruk secara In vitro
Abstrak: Drought stress could be simulated by decreasing the water potensial media through polyethylene glycol (PEG) addition. The objective of this experiment was to explain the effect of drought stress to some citrus rootstocks growth under in vitro conditions. The experiment used a factorial completely randomized design (CRD). The first factor was PEG addition which consist of four level: 0 g l-1 PEG is equivalent to 0% (0 bar), 20 g l-1 PEG is equivalent to 2% (-0.12 bar), 40 g l-1 PEG is equivalent to 4% (-0.32 bar), 60 PEG g l-1 is equivalent to 6% (-0.59 bar). The second factor was citrus rootstock varieties, which consist of Rough Lemon, Kunci-10, and Nipis. The result showed that all of the parameters decreased with the increasing of osmotic stress by PEG. Three varieties showed same response toward PEG addition on the last week of observation. Kunci-10 and Nipis have more stability under drought stress simulation rather than Rough Lemon.
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Judul: Optimization of Basic Media and Growth Regulator for In Vitro Multiplication of Jeruk Kunci (Citrus x microcarpa Bunge) Plant
Abstrak: Jeruk kunci (Citrus x microcarpa) merupakan tanaman jeruk dengan habitus semak yang banyak tumbuh di wilayah Bangka-Belitung. Jeruk ini memiliki banyak manfaat baik secara langsung atau tidak langsung. Akan tetapi, pertumbuhan dan perkembangbiakannya lambat, sehingga salah satu upaya memperbanyak tanaman tersebut ialah dengan kultur in vitro. Penelitian ini bertujuan menentukan kombinasi antara media dasar MS atau DKW dengan BAP yang optimal untuk multiplikasi tunas jeruk kunci secara in vitro. Penelitian ini menggunakan RAL dengan dua faktor, yakni jenis media dan taraf konsentrasi BAP. Pemberian BAP pada 0,1-2,0 mg/L ke dalam media MS atau DKW mampu menginduksi kalus dan tunas adventif dibandingkan tanpa BAP. Perlakuan DK3 dan DK4 menunjukkan waktu muncul kalus tercepat pada minggu kedua, sedangkan waktu muncul tunas adventif secara berurutan juga paling cepat pada minggu ketiga dan kelima. Rata-rata jumlah tunas adventif (7,2 tunas), tinggi tunas (2,14 cm), jumlah tunas aksilar (19,6 tunas), dan jumlah daun (50,4 helai) tertinggi ditunjukkan oleh perlakuan DK3., Citrus x microcarpa, given in Indonesia as jeruk kunci, is a citrus plant with a shrub habitus that grows in the majority in the Bangka-Belitung Islands, offering numerous direct and indirect benefits. However, its growth and reproduction are slow, so one of the efforts to reproduce the plants is by in vitro culture. This study aimed to determine an optimal combination of MS or DKW basic media with benzyl amino purine (BAP) growth regulator to get multiple shoots in vitro. This study was designed in CRD with two factors: the basic media type and BAP concentration levels. The provision of BAP at 0,1-2,0 mg/L added to MS or DKW media induced callus and adventitious buds compared to the control without BAP. The DK3 and DK4 treatments showed the fastest callus emerging time, which was in the second week, while adventitious buds were also obtained the most rapid in both media, the third and fifth weeks, respectively. The highest average number of adventitious buds (7,2 buds), shoot height (2,14 cm), number of axillary buds (19,6 buds), and number of leaves (50,4 leaves) were shown by treatment DK3.
Keyword: adventitious bud, axillary bud, BAP concentration, basic medium

Judul: Formulasi Hamiltonian untuk Menggambarkan Gerak Gelombang Soliter Dimensi Tiga di Permukaan Laut
Abstrak: Gelombang permukaan adalah gelombang yang terjadi perbedaan rapat massa antara air dan udara. Salah satu gelombang permukaan yang ditinjau adalah gelombang soliter. Formulasi gelombang soliter dilakukan dengan menggunakan formulasi Hamiltonian.
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