Judul: The Ability of Endophytic Fungi from Pilea microphylla (L.) Leibm In Indole Acetic Acid Production
Abstrak: Pilea microphylla (L.) Liebm. merupakan herba sukulen yang memiliki kemampuan toleran cekaman kekeringan. Kemampuan tersebut mungkin terkait dengan keberadaan cendawan endofit dalam jaringan P. microphylla dan dapat menghasilkan metabolit sekunder di antaranya asam indol asetat (IAA) atau auksin. Namun, kemampuan dan waktu optimum cendawan endofit asal P. microphylla dalam menghasilkan IAA belum diteliti. Penelitian ini bertujuan mengukur konsentrasi auksin yang dihasilkan oleh isolat cendawan endofit PM 2A2.3 dan PM 2A2.4 asal P. microphylla pada berbagai waktu inkubasi. Hasil penelitian menunjukkan bahwa morfologi koloni dua kultur pada medium PDA berwarna putih dengan tekstur miselium berupa cottony. Namun dua kultur memiliki tipe pertumbuhan miselium berbeda yaitu miselium PM 2A2.3 tumbuh ke atas substrat (aerial), sedangkan miselium PM 2A2.4 merata (non aerial). Dua kultur menghasilkan konsentrasi IAA paling banyak pada masa inkubasi 2 minggu, yaitu 27,61 ppm oleh PM 2A2.4 dan 19,68 ppm oleh PM 2A2., Pilea microphylla (L.) Liebm is a succulent herb which tolerates drought stress. This fitness may be related to endophytic fungi in P. microphylla tissue and could produce secondary metabolites, including indole acetic acid (IAA). However, the ability and optimum time of endophytic fungi from P. microphylla to produce IAA have not yet been studied. This study aimed to measure the concentration of IAA produced by isolates of endophytic fungi PM 2A2.3 and PM 2A2.4 from P. microphylla at various incubation times. The colony morphology on the PDA medium from both isolates was white with a cottony mycelium texture. Both cultures had different types of mycelium growth, that was PM 2A2.3 had aerial mycelium, while PM 2A2.4 was evenly distributed (non-aerial). The isolates of PM 2A2.4 and PM 2A2.3 produced the highest concentrations of IAA at two weeks of incubation, that is 27.61 and 19.68 ppm, respectively.
Keyword: drought stress, IAA, potato dextrose broth, succulent herb

Judul: Kemampuan bakteri endofit Micrococcus endophyticus G053 dalam memproduksi IAA-like compound dan meningkatkan pertumbuhan tanaman
Abstrak: Endophytic bacteria are able to act as PGPB (plant growth-promoting bacteria) by producing hormones or increasing availability nutrients for plants. This study aimed to test the ability of endophytic bacterium Micrococcus endophyticus G053 to produce IAA-like compound, fix free nitrogen, and its ability to increase potato plantlet and tobacco plant growth. The ability of M. endophyticus G053 to produce IAA-like compound in TSB 50% and TSB 100% was tested using Salkowski reagent, whereas its ability to fix free nitrogen was tested by growing it in LGI agar. Potency of M. endophyticus G053 to increase plants growth was tested in vitro using potato plantlets and in planta using tobacco plants. The results showed that M. endophyticus G053 was able to produce IAAlike compound in both media and to fix free nitrogen. The highest production of IAA-like compound was at 6th day of incubation in TSB 50% (64.35 ppm) and at 8th day of incubation in TSB 100% (69.10 ppm). Potato plantlets inoculated with M. endophyticus G053 was able to increase plantlet height and its number of shoot. M. endophyticus G053 inoculated in tobacco plants rhizosphere was also able to increase shoot length, root length, and dry weight of tobacco plants. The ability of M. endophyticus G053 to increase potato plantlets and tobacco plants growth was due to their ability to produce IAA-like compound and to fix free nitrogen.
Keyword: Bogor Agricultural University (IPB), nitrogen-fixing bacteria, Micrococcus endophyticus G053, indole-3-acetic acid (IAA), endophytic bacteria

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