Judul: Penggunaan Bakteri Pelarut Fosfat serta Kombinasinya a pada Pertumbuhan Tanaman Sawi Sendok
Abstrak: Phosphorus is one of the essential elements which plays a very important role in photosynthesis and root development. Most of the phosphate forms are bound in soil colloids, so that it is not available for plants. A group of the so called phosphate-solubilizing microorganisms (PSM) have ability to solubilize a bounding phosphate because they produce organic acid so that they can increase the efficiency of phosphate fertilization. Naturally phosphate-solubilizing microorganism live in the rhizosphere. The research activities covered isolation of PSM, antagonistic test, phosphate solubilizing test, and the use of phosphate solubilizing bacteria (PSB) isolates combined with SP-36 fertilizer on the growth of sawi sendok plant. Soil samples for microbe isolation were taken from Semplak. The experiment was conducted at green house condition. The experiment was arranged according to completely randomized design (CRD) with two treatment factors provided and three replications. The first factor was phosphate solubilizing bacteria isolates namely Burkholderia sp. IS9, Pseudomonas aeruginosa P2, Bacillus subtilis J2, and Burkholderia sp. PS4. The second factor was phosphate fertilization, i.e 50%, 75% and 100% dosages of SP-36 fertilizer. The result of the experiment showed that bacteria Burkholderia sp. IS9 isolate provided higher phosphate solubilizing capacity of the qualitative and quantitative ability test of phosphate solubilizing compared to other treatments. The inoculation of Burkholderia sp. PS4 with 50% dosage of SP-36 fertilizer increased plant height, biomass and plant dry weight.
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Judul: The utilization of phosphate solubilizing bacteria to providing phosphate for the growth and production of pakchoy plant
Abstrak: Phosphorus is an essential macro nutrient needed for plant growth and has an important function in the metabolic process. The function of phosphorus in plants for cell growth, the formation of fine roots and root hairs, the stems to strengthen the standing crop for not easy to fall, the formation of flowers, fruits and seeds, and strengthen resistance to disease. In soil, organic and inorganic phosphorus, both of which are an important source for plants. Plants absorb phosphorus in the form of H2PO4-, HPO42- dan PO43-. One of the alternative to improving the efficiency of phosphate fertilizer to utilize the phosphate solubilizing microbial groups. Pakchoy is a vegetable crops, including to Brassicaceae family. Pakchoy have a high economic value. These plants thrive in tropical and subtropical regions This research aims to study about the four isolates of phosphate solubilizing microbes (BPF) applied either single or in combination to enhance the growth and production of pakchoy plant and in reducing the use of inorganic phosphates.This research was started from January 2012 to July 2012 in the Soil Biotechnology Laboratory Departement of Soil Science and Land Resources and Land owned by CV. Agro Meori Jl.Atang Sanjaya KM 4 Sand Gauk, Bogor and implemented in two stages, i.e. in vitro and in vivo (greenhouse). . The results of in vitro studied showed that Burkholderia sp. T9 has a high value of Solubilization Index (SI) (3.47) and the solubilizing of phosphate in Pikovskaya liquid medium (4.9 ppm). The results for CV.Meori Agro bacterial isolates collection showed that the Burkholderia sp. PS4 has a high value of Solubilization Index (SI) (1.56) and Pseudomonas aeruginosa P2 has a high value for solubilizing of phosphate in Pikovskaya liquid medium (1.3 ppm). A high value of enzyme activities showed by Burkholderia sp. T9 (0,268 ppm). The results of in vivo studied showed that the best value of leaves number was the combination of Pseudomonas aeruginosa P2 + Burkholderia sp. PS4 (17.18%). The highest average leaf width was shown by Burkholderia sp. PS4 ( 4.83%). Wet weight of plants with the best results was shown by Burkholderia sp. PS4 i.e. 0.42%. The highest nutrient uptake of P was shown by Burkholderia sp. PS4 (0,44%) .The best average P in plant tissues was shown by a combination of P2 + PS4 + T9 i.e. 0,42%. The best average of P in soil was shown by the combination T9 + P2 i.e. 1,25%.
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Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular