Judul: Pemanfaatan Bakteri Rhizoplane dan Fungi Mikoriza Arbuskula (FMA) Untuk Meningkatkan Pertumbuhan Semai Jelutung (Dyera polyphylla Miq. Steenis.)
Abstrak: Nontimber forest products (NTFPs) represent sources of income from tropical forest, but some NTFP species have decreased in population and become endangered due to overexploitation. There is increasing concern that the planting stock of Dyera polyphylla is not sufficient to sustain the yield of NFTPs. The beneficial root colonizing rhizosphere bacteria, the so-called plant growthpromoting rhizobacteria have been known to carry out many important ecosystem processes, such as those involved in the nutrient cycling and/or seedling establishment. The roots of most plant species associate with certain soil fungi and establish what are known as mycorrhiza. The objective of this study was to determine the effect of two arbuscular miycorrhizal (AMF) fungi, Glomus sp., Gigaspora sp. and thirteen strains of rhizoplane bacteria (CK32, FL.13.2.1, JW1, JW6, JW9, JW13, JW14, CK26, CK4, JW3a, SB, NT, CR.R1), on the early growth of D. polyphylla, under greenhouse condition. Percentage of AMF colonization, plant growth, and nitrogen (N) and phosphorus (P) concentration were measured after 150 days of planting. The results showed that the percentage of AM colonization of D. polyphylla was 100%. Colonization by Glomus sp. significanly increased plant height by 18,95% and diameter by 16,16% compared to those non AMF. Combination of bacterial and AMF inoculant between JW13 dan Glomus sp. increased shoot weight by as much as 36,28% from control and increased N concentration by 69,59% compared to those of non inoculate a seedlings. Combination of JW1 and Gigaspora sp. increased P concentration by as much as 42,05% compared to those of non inoculate seedlings. Despite the difficulty of selecting a multifunctional microbial consortia, appropriate microbial combinations can be recommended for a biotechnological input related to improvement of plant performance.
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Judul: Pemanfaatan Mycorrhizal Helper Bacteria (MHBs) dan Fungi Mikoriza Arbuskula (FMA) untuk Meningkatkan Pertumbuhan Semai Gmelina (Gmelina arborea Roxb.)
Abstrak: INTRODUCTION. Increase in the size of human population causes an ever increasing demand on paper produtcs. Therefore, there is a need to supply wood as raw materials in rapid manner. In relation with this, the Indonesian government has a policy to develop Industrial Plantation Forest (HTI). Gmelina is one of the forest tree species which has good prospect to be developed in Industrial Plantation Forest (HTI). This species is a fast growing species which could grow in various types of soil, and its wood is considerably useful. Development ofHTI in Indonesia is emphasized on critical land. The use of Arbuscular Mycorrhizal Fungi (AM F) is an appropriate solution for promoting plant growth in such condition. In the field, AMF had some constraints in creating symbiosis with host plants, Therefore, in this case, there is a need for bacteria which stimulates the AMF. One such bacteria, is known with the name Mycorrhizal Helper Bacteria (MHBs). MATERIALS AND METHOD. This research used Factorial Completely Randomized Design comprising 16 treatments, 5 replications and 3 units. Inoculation of mycorrhizal fungi and bacteria was conducted when the seedlings were 3 weeks old. Afterwards, observation was conducted for 3 months. For observing the plant's respond toward treatments, the observed parameters were among other things: height, diameter, root biomass, shoot biomass, shoot - root ratio, Index of Seedling Quality, and percentage of mycorrhizal infection. RESULTS AND CONCLUSION. Results of Analysis of Variance showed that mycorrhizal treatment had significant effect on parameters of root biomass and percentage of mycorrhizal infection. On the other hand, combined treatments of mycorrhiza and bacteria had significant effect toward parameter of root biomass. Combination of mycorrhiza with isolate BGLo3 gave the highest percentage of mycorrhizal infection, namely 25.49 %. Inoculation of isolate BGLo1 gave the best respond for parameters of height and diameter. Consecutively, the exhibited increases were 32.33 % and 31.25 % as compared with those of control. Combination of mycorrhiza with BGLo3 also exhibited the highest increase as compared with control, in terms of parameters of root biomass and Index of Seedling Quality, namely 2.28 % and 87.89 %. Inoculation ofmycorrhiza without bacteria exhibited the best respond for parameters of shoot - root ratio, namely with increase by 9.23 % as compared to control.
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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