Judul: Vigor Of Lime Seed (Citrus Amblycarpa Hassk. Ohcse) On Saline And Drought Conditions
Abstrak: Lime is cultivated in many countries as food ingredient, food fragrances, flavorings and face cleaner. The crop is propagated by seeds generatively or by grafting vegetatively. There are limited information available on lime’s seed vigor in stress conditions. The research was consist of two experiment, i.e. saline and drought conditions. The experiment was conducted at the Laboratory of Seed Science and Technology IPB from March to July 2015. The objective of this research was to provide information related to vigor of lime seed in saline and drought conditions. First experiment was tested the vigor of lime seeds in different saline conditions by using NaCl, i.e. 0 ppm, 1500 ppm, 3000 ppm and 4500 ppm. Second experiment tested the vigor of lime seeds in different drought conditions using PEG 6000 at 0 bar, -0.75 bar, -1.5 bar and -2.25 bar. The experiment elucidated that saline and drought conditions significantly decreased germination percentage, vigor index and dry weight of normal seedling. The higher the concentration of NaCl (salinity condition) or PEG 6000 (drought condition), the smaller the germination percentage of lime seeds.
Keyword: drought, lime seed, saline, vigor

Judul: In Vitro Germination and Growth of Lime (Citrus aurantifolia) for Selection of Endophytic Bacteria to Control Huanglongbing Disease
Abstrak: Kendala yang sering dialami dalam pertanaman jeruk adalah tingginya serangan penyakit, salah satunya adalah penyakit Huanglongbing (HLB). Pengendalian HLB dapat dilakukan dengan memanfaatkan agen hayati berupa bakteri endofit. Teknik infeksi buatan serangan HLB secara in vitro telah berhasil dikembangkan sehingga seleksi bakteri endofit dapat dilakukan dengan lebih cepat. Jeruk nipis dipilih sebagai eksplan seleksi karena sangat peka terhadap serangan HLB. Penelitian ini bertujuan mendapatkan konsentrasi giberelin dan perlakuan skarifikasi terbaik untuk perkecambahan in vitro jeruk nipis, serta mengetahui isolat bakteri endofit terbaik dan lama perendaman optimal untuk pengendalian HLB. Pada tahap pertama penelitian, biji jeruk nipis dengan dan tanpa perlakuan skarifikasi dikecambahkan pada media dasar MS+VMW dengan tambahan giberelin 0 mgL −1 , 5 mgL −1 , 10 mgL −1 , dan 15 mgL −1 . Pada tahap kedua, tunas jeruk hasil perkecambahan direndam selama 1, 2, dan 3 hari dalam 7 suspensi isolat bakteri endofit yang berbeda lalu diinfeksi buatan secara in vitro dengan suspensi bakteri CLas, patogen HLB. Hasil penelitian menunjukkan bahwa konsentrasi giberelin optimal untuk menginduksi perkecambahan biji jeruk nipis adalah 5 ml −1 . Perlakuan skarifikasi secara nyata mampu mempercepat waktu berkecambah. Bakteri endofit Micrococcus endophyticus memberikan hasil lebih baik dalam mengurangi gejala infeksi HLB dibandingkan bakteri endofit Bacillus spp. Lama perendaman tunas jeruk dalam suspensi bakteri endofit optimal untuk mengurangi gejala infeksi Clas adalah 3 hari., The problem that is often experienced in citrus cultivation is the high incidence of diseases, one of which is Huanglongbing disease (HLB). HLB control can be done by utilizing biological agents in the form of endophyte bacteria. In vitro artificial infection techniques for HLB attacks have been developed so that selection of endophyte bacteria can be carried out more quickly. In vitro lime sprouts were chosen as the explants of selection because of its sensitivity to HLB attack. This study aims to obtain the best gibberellin concentration and scarification treatment for in vitro lime germination, as well as to determine the best endophyte bacterial isolates and optimal immersion time for HLB control. In the first stage of the research, seeds with and without scarification treatment were germinated on MS+VMW base medium with the addition of 0 mgL −1 , 5 mgL −1 , 10 mgL −1 , and 15 mgL −1 gibberellin. In the second stage, the shoots were cultured for 1, 2, and 3 days in 7 different endophyte bacterial suspensions and then infected with CLas bacteria, the pathogen of HLB. The results of this research indicate that the optimal concentration of gibberellin to induce lime germination is 5 mgL −1 . The scarification treatment significantly accelarated the germination time. Endophyte bacteria Micrococcus endophyticusshowed better results in reducing the symptoms of HLB infection than the endophyte bacteria Bacillus spp. The optimal duration of inoculation to reduce the symptoms of CLas infection was 3 days.
Keyword: Gibberellin, infection, inoculation, scarification

Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf