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: Penggunaan Mycorrhizal Helper Bacteria (MHBs) dan Fungi Mikoriza Arbuskula (FMA) Untuk Meningkatkan Perturnbuhan Semai Mindi (Melia azedarach Linn.)
Abstrak: Introduction. High rate of forest degradation in Indonesia causes reduction of forest area and increase of critical land area. In the efforts to reduce the impacts from such forest damage. land and forest rehabilitation is conducted. However, the main constraint for the success of rehabilitation is the retarded growth of planting stocks (seedlings) and low survival rate of the seedlings. For overcoming such problem, good quality seedlings, which could survive in marginal lands are required. For obtaining good quality seedlings which have high survival rate in the field, there is a need for sufficient input of nutrients through fertilizer application. The applied fertilizer should be environmentally friendly. The use of soil microbe technology, namely the use of mycorrhiza is an appropriate solution and has been proven to be able to increase plant growth. One of the mycorrhizal fungi which can be used as biofertilizer is AMF (Arbuscular Mycorrhizal Fungi). Symbioses between fungi and plant roots often suffer some constraints in the field. Therefore, there is a need for microorganism which could give positive effects for improving such cooperation. Such organism is bacteria species which is known as Mycorrhizal Helper Bacteria (MHBs). MHBs is a specific bacteria which is able to have symbioses with AMF and is able to stimulate the development of AMF. The application of MHBs and AMF on mindi is expected to be able to increase the growth and quality of mindi seedlings. Methodology. A completely randomized design two factors (Micorrhizal and Bacteria) was employed to examine the effect of mycorrhizal and bacteria on the plant growth. The parameter observed were: mycorrhiza infection percentage, height, diameter, shoot biomass, root biomass, shoot - root ratio and Index of Seedling Quality (1MB). Results and conclusion. Isolate of bacteria BGG02 which was combined with AMF Gigaspora sp (M2) gave the highest increase in mycorrhiza infection percentage, namely 58.3% as compared to mycorrhiza treatment without bacteria. Isolate BGG03 was more effective in increasing the mycorrhiza infection percentage if combined with Glomus sp (M1), namely 18.8%, whereas application of isolates BGG01 and BGG04 increased the percentage of mycorrhiza infection 1.8% when combined with mixture of AMF Glomus sp and Gigaspora sp (M1 M2). Application of bacteria, AMF or combination of them, gave positive effects toward mindi growth. Combination of isolate BGG01 and AMF Gigaspora sp (M2B1) gave the best respond toward parameters of height, diameter, root biomass, shoot biomass and Index of Seedling Quality (1MB), with increase value of respectively 352.7%, 4.8%, 2809.7%, 4545.7% and 488.3% as compared to control. In general, during the application of AMF, application of Gigaspora sp (M2) gave the greatest positive effect toward mindi growth as compared with application of other AMF, namely Glomus sp (M1) and mixture of Glomus sp and Gigaspora sp (M1 M2).
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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