Judul: Studi Kolonisasi Rizobakteria Pemacu Tumbuh Tanaman Pseudomonas sp. dan Bacillus sp. di Rizosfer Tanaman Kedelai
Abstrak: Rhizosphere is a portion of soil affected by substances released by roots (root exudates), which are substrates for microbial growth, thereby triggering a competition amongst various microorganisms to colonize the rhizosphere. The survival and colonization of Pseudomonas sp. Crb 17, Crb 64, and Bacillus sp. Cr 76 were tested in the rhizosphere of soybean grow on sterile and non-sterile soil for six weeks. A marker used to monitor the dynamic population of the isolates in the rhizosphere was rifampicin resistance marker. Based on the results obtained, the rhizosphere colonization ability of these three isolates in the sterile soil was not significantly different (α = 0.05) from that in non-sterile soil, although there was a tendency of higher population in sterile soil compared to non-sterile soil. Colonization ability amongst the isolates was also not significantly different (α = 0.05) both in sterile and non-sterile soil. However, in non-sterile soil, colonization ability of isolate Crb 64 was better than that of two isolates. Isolate Crb 64 is the most competitive isolate in colonizing soybean rhizosphere. In general, all isolates have high ability to colonize and survive in the soybean rhizosphere as shown by their high population numbers until the end of the observation period, i.e. around 6 to 7 log cells/g dry soil.
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Judul: Studi Kolonisasi Rizobakteria Pemacu Tumbuh Tanaman Pseudomonas sp. dan Bacillus sp. di Rizosfer Tanaman Kedelai
Abstrak: Rhizosphere is a portion of soil affected by substances released by roots (root exudates), which are substrates for microbial growth, thereby triggering a competition amongst various microorganisms to colonize the rhizosphere. The survival and colonization of Pseudomonas sp. Crb 17, Crb 64, and Bacillus sp. Cr 76 were tested in the rhizosphere of soybean grow on sterile and non-sterile soil for six weeks. A marker used to monitor the dynamic population of the isolates in the rhizosphere was rifampicin resistance marker. Based on the results obtained, the rhizosphere colonization ability of these three isolates in the sterile soil was not significantly different (α = 0.05) from that in non-sterile soil, although there was a tendency of higher population in sterile soil compared to non-sterile soil. Colonization ability amongst the isolates was also not significantly different (α = 0.05) both in sterile and non-sterile soil. However, in non-sterile soil, colonization ability of isolate Crb 64 was better than that of two isolates. Isolate Crb 64 is the most competitive isolate in colonizing soybean rhizosphere. In general, all isolates have high ability to colonize and survive in the soybean rhizosphere as shown by their high population numbers until the end of the observation period, i.e. around 6 to 7 log cells/g dry soil.
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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