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: Effectiveness of Several Commercial Product  as the Source of Plant Growth Regulators in the Growth of Phalaenopsis amabilis  Protocorm
Abstrak: Phalaenopsis amabilis merupakan salah satu jenis anggrek yang popular dengan keindahan bunganya. Perbanyakan anggrek P. amabilis melalui protocorm dapat menghasilkan tanaman dalam jumlah besar dan genetik yang stabil Pertumbuhan normal pada protocorm dibutuhkan untuk mendapatkan planlet dengan kualitas yang baik sebelum aklimatisasi. Penelitian bertujuan mempelajari keefektifan beberapa sumber ZPT alternatif dalam pertumbuhan protocorm P. amabilis. Penelitian ini menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) dengan faktor tunggal. Bahan tanam yang digunakan adalah protocorm P. amabilis yang dihasilkan benih yang berasal dari bunga hasil penyerbukan sendiri (selfing). Benih ditabur pada media 1⁄2 MS + air kelapa 15% + gula 30 g + agar 7 g per liter pada tanggal 23 September 2020. Protocorm yang berumur 6 bulan setelah perkecambahan dipindahkan ke 10 perlakuan media perbanyakan yang mengandung zat pengatur tumbuh (zpt) alternatif yaitu 1⁄2 MS (K0), (1⁄2 MS + 0,25 ml L-1 Atonik (A1), 1⁄2 MS + 0,5 ml L-1 Atonik (A2), 1⁄2 MS + 1 ml L-1 Atonik (A3), 1⁄2 MS + 0,025 ml L-1 Agrogibb (G1), 1⁄2 MS + 0,05 ml L-1 Agrogibb (G2), 1⁄2 MS + 0,075 ml L-1 Agrogibb (G3), 1⁄2 MS + 0,5 ml L-1 NovelGro (N1), 1⁄2 MS + 1 ml L-1 NovelGro (N2), 1⁄2 MS + 2 ml L-1 NovelGro (N3). Protocorm dibedakan menjadi tiga ukuran yaitu kecil, sedang dan besar. Setiap perlakuan zpt alternatif memiliki tiga ulangan (tiga kelompok ukuran) dengan lima protocorm pada masing-masing botol, masing-masing tiga botol per perlakuan. Protocorm diamati untuk mendapatkan persentase eksplan hidup, jumlah tunas, waktu terbentuk tunas, jumlah daun, jumlah akar, panjang daun, lebar daun dan panjang akar. Protocorm sedang ditandai dengan ukurannya yang sedang dan bentuk bulat tanpa tonjolan. Perlakuan terbaik pertumbuhan protocorm adalah 1⁄2 MS (K0). Media ini menunjukkan tidak adanya pertumbuhan abnormal protocorm. Perlakuan 1⁄2 MS + 0,075 ml L-1 Agrogibb (G3) mampu mendukung pemanjangan protocorm, tunas dan daun. Protocorm besar menghasilkan jumlah tunas paling banyak pada 4 dan 5 MST. Protocorm besar juga menghasilkan jumlah daun dan jumlah akar paling banyak pada 6 MST. Kata kunci: Agrogibb, Atonik, NovelGro, Phalaenopsis amabilis, Protocorm., Phalaenopsis amabilis is one of the most popular orchid’s species caused by its beautiful flower. Multiplication P. amabilis by using protocorm can produce plants with high quantity and stable genetics. The normal growth of the protocorm is needed to get good quality plantlets before acclimatization. The research aimed to study the effectiveness of several alternative plant growth regulators on the growth of P. amabilis protocorm. This research was arranged in a Randomized Complete Block Design with alternative growth regulators as the single factor. The plant material used was protocorm of P. amabilis resulting from seed from flower self-pollination. The seeds were germinated on 1⁄2 MS medium + 15% of coconut water + 30 g of sucrose + 7 g of agar per liter on 23 September 2020. Protocorm at 6 months after germination were transferred to 10 treatments of multiplication medium containing alternative source of plant growth regulators namely 1⁄2 MS (K0), (1⁄2 MS + 0.25 ml L-1 Atonik (A1), 1⁄2 MS + 0.5 ml L-1 Atonik (A2), 1⁄2 MS + 1 ml L-1
Keyword: Agrogibb, Atonik, NovelGro, Phalaenopsis amabilis, Protocorm

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