Judul: Phalaenopsis sp. Growth Improvement through Nutrient Optimation.
Abstrak: Standard Operating Procedure (SOP) of Phalaenopsis sp. fertilization based on plant tissue analysis has not been developed in Indonesia. The basis development of SOP was executed on the two following research. The main research was conducted in the green house of Agropromo, Baranang Siang, Bogor and the supporting research was conducted in the green house in Gunung Batu, Bogor. The objectives of this study were (1) to establish the class of nutrient status of Phalaenopsis sp. (2) to study the optimation of nutrient concentrations (nitrogen, phosphorus, and potassium) applied through the leaves of Phalaenopsis sp., and (3) to study the Phalaenopsis sp. growth in the treatment of high concentrations of nitrogen, phosphorus, and potassium fertilizer with initial low pH conditions. The main research was aimed to find the class of nutrient status and optimize the nutrient of Phalaenopsis hybrid (Casablanca JDX x Diamond) # 1 x (Casablanca dream x self) #1. Plants were fertilized with N, P, and K in three separated experiments. The treatment were (1) 0, 65, 105, 157, 210 ppm nitrogen, (2) 0, 20, 40, 60, 80 ppm phosphorus, and (3) 0, 115, 230, 345, 390 ppm potassium. The results showed no effect of treatments on leaf water content, plant length, leaf area, stomatal density, leaf thickness, total chlorophyll content, anthocyanin content, and glucose content in all experiment. Nitrogen treatment produced significant effect on the increase in the number of leaves on 12 and 16 WAT (Weeks After Treatment), leaf greenness on 8 WAT, and leaf weight on 16 WAT. Phosphorus treatment produced significant effect on leaf greenness on 8 and 16 WAT, nutrient uptake on 16 WAT, and nutrient content in leaf tissue on 8 and 16 WAT. Potassium treatment produced significant effect on leaf dry weight on 8 WAT, nutrient content in leaf tissue on 8 WAT, and nutrient uptake on 16 WAT. Significant plant response was analyzed by polynomial contrast test. The class of nutrient status that could be set for nitrogen, phosphorus, and potassium treatment were very low, low, adequate, and high with the limit of nutrient content in the leaf tissue and leaf greenness in certain value. Nutrient optimation in nitrogen treatment was 89.33 ppm for leaf greenness on 8 WAT. Nutrient optimation in phosphorus treatment was 50.41 ppm for leaf greenness on 8 WAT. Nutrient optimation in potassium treatment could not be done because the variable of vegetative production (leaf greenness) was not significant in quadratic response. These results would be used as fertilizer recommendation. Before the main research, supporting research conducted to determine the limits of concentration and pH of the foliar fertilizer will be given. In the supporting research, we examined Phalenopsis amabilis accession “Trenggalek” responses at different pH of high concentration N (nitrogen), P (phosphorus), and K (potassium) fertilizer, in three separated experiments. Fertilizer was given at low pH (pH=2.5-4) and continued with neutral pH (pH=6.6), in high concentration which were (1) 431.417 ppm N (0-4 WAT); (2) 398 ppm P (0-2 WAT), 199 ppm P (2-4 WAT); and (3) 506 ppm K (0-4 WAT). No effect of treatments on
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Judul: Pertumbuhan dan Ketahanan terhadap Penyakit Busuk Lunak pada Anggrek Phalaenopsis dengan Pemupukan dan Asam Salisilat.
Abstrak: Maintaining is one of the important processes in Phalaenopsis plants cultivation to get high quality plants. Practically, it is aimed to promote plant grow quickly, healthy and free of diseases. One of main disease on Phalaenopsis is soft rot which caused by Dickeya dadantii bacteria. The use of resistant varieties, application of NPK fertilizers and salicylic acid for growth and resistance are alternatives that can be used to prevent the disease. The purposes of this study were to analyze the Phalaenopsis orchid resistance to soft rot diseases that caused by D. dadantii, determine the effect of NPK fertilizer and salicylic acid concentration as well as the interaction between them for growth and resistance to soft rot diseases caused by D. dadantii. The experiments were conducted at the Bacterial Plant Laboratory, Department of Plant Protection and Greenhouse Leuwikopo, Bogor Agriculture University and plastic house Alam Sinar Sari Dramaga, Bogor, Indonesia. The treatments used for the first experiment were five Phalaenopsis hybrids, namely Phal. KHM 205, Phal. KHM 1126, Phal. KHM 1318, Phal. AMP 17, and Phal. KHM 2249. Phal. amabilis and Phal. amboinensis used as control. Phalaenopsis hybrids used in the second experiment were Phal. KHM 1318 and Phal. KHM 205. The first factor was NPK concentration (0, 1000 and 2000 ppm) and the second one was the concentration of salicylic acid (0, 5 and 10 ppm). The resistance test on some genotype of Phalaenopsis to D. dadantii showed that all Phalaenopsis hybrid had the symptoms of soft rot disease. Phal. KHM 2249 which had the lowest number of leaves reduction and the highest number of life plants after infection was indicated as resistance genotype relatively compared to others in the experiment. The resistance could be came from highest peroxidase activity, low leaf thickness and water content that were not appropriate for pathogen development. The results in the second experiment showed that NPK fertilizer increased growth of Phal. KHM 1318 and Phal. KHM 205. NPK fertilization 1000 and 2000 ppm showed the same effects on all growth variables. Salicylic acid did not have significant effect in improving plant growth. The increased of NPK concentrations reduced plant resistance to soft rot disease which could be seen from increasing of disease symptoms area and the number of fallen leaves and decreasing of the number of life plants after soft root infection on both genotype. Salicylic acid application on Phal. KHM 1318 could not improve plant resistance to soft root although it increased peroxidase activities. Adversely on Phal. KHM 205, salicylic acid could decreased disease symptom area but did not increased peroxidase activity.
Keyword: D. dadantii, leaf thickness, leaf water content, PAL, peroxydase

Judul: Invers dari Matriks Tridiagonal Jacobi
Abstrak: Suatu matriks berukuran n×n dinamakan matriks tridiagonal jika untuk . Karya ilmiah ini memberikan algoritma yang mudah untuk menemukan invers ( dari matriks tridiagonal Jacobi yang simetrik dan nonsimetrik. Setiap elemen pada matriks tridiagonal ini adalah bilangan real. Terdapat 3 lema dan 2 teorema untuk menentukan . Lema pertama menunjukkan persamaan utama dalam membuktikan lema-lema dan teorema-teorema selanjutnya. Invers dari matriks yang simetrik dibuktikan oleh lema kedua yang menunjukkan elemen-elemen baris ke- dari . Selanjutnya, lema kedua dilengkapi dengan teorema pertama yang menunjukkan elemen-elemen dengan . Invers dari matriks yang nonsimetrik dibuktikan oleh lema ketiga yang menunjukkan elemen-elemen dengan dan elemen-elemen dengan dibuktikankan oleh teorema kedua.
Keyword: symmetric, nonsymmetric, matrix