Judul: Seed Viability of Mahogany (Swietenia macrophylla King.) at Different Temperatures and Storage Time
Abstrak: Swietenia macrophylla atau mahoni berdaun lebar adalah jenis eksotik dari Amerika Tengah dan Selatan. Pohon ini memiliki berbagai manfaat dan kegunaan. Penyimpanan benih masih menjadi permasalahan yang utama, karena dapat menurunkan viabilitas benih. Daya simpan benih dipengaruhi oleh kondisi benih dan kondisi lingkungan. Oleh karena itu, penelitian ini bertujuan menguji pengaruh suhu dengan masa simpan terhadap viabilitas benih mahoni serta menghitung Indeks Mutu Bibit (IMB). Percobaan dilakukan menggunakan Rancangan Acak Kelompok (RAK) faktorial dengan 2 faktor. Faktor pertama terdiri atas empat taraf perlakuan suhu yaitu suhu ruang (24 °C), 4 °C, 0 °C, dan -20 °C. Faktor kedua yaitu perlakuan masa penyimpanan yang terdiri atas 4 taraf yaitu 1 sampai 4 minggu, dengan interval 1 minggu. Hasil penelitian menunjukkan bahwa interaksi suhu dan masa simpan memengaruhi jumlah daun, jumlah akar primer dan sekunder, nisbah tajuk akar, dan bobot basah total bibit mahoni. Benih mahoni yang disimpan pada suhu kamar selama 1 minggu menghasilkan viabilitas benih terbesar, dengan benih mahoni yang disimpan pada suhu ruang selama 1 minggu menghasilkan viabilitas benih tertinggi sebesar 80%, IMB dengan nilai 0,03 ̶ 0,04., Swietenia macrophylla or big-leaf mahogany is an exotic species from Central and South America. This tree has various benefits, so it’s used as an industrial plantation forest and afforestation in Indonesia. However, seed storage of mahogany is a major problem in cultivation, because it can reduce seed viability. The storability of seeds is influenced by seed and environmental conditions. Therefore, this study aimed to examine the effect of temperatureand storage time on the viability of S. macrophylla seeds and to calculate the Seedling Quality Index (SQI). The experiment was carried out using a factorial Randomized Block Design (RBD) with 2 factors. The first factor has consisted of four levels of temperature treatment, namely room temperature (24 °C), 4 °C, 0 °C, and -20 °C. The second factor was the storage period treatment which consisted of 4 levels, namely 1 up to 4 weeks, with 1-week intervals. The results showed that the interaction between temperature and storage time affected the number of leaves, primary and secondary roots, root/shoot ratio, and total wet weight of S. macrophylla seedlings. Mahogany seeds that were stored at room temperature for 1 weekresulted in the highest seed viability, with SQI of 0,.03 - 0,.04.
Keyword: Bobot basah, indeks mutu bibit, mahoni berdaun lebar, viabilitas

Judul: Pertumbuhan Bibit Mahoni (Swietenia macrophylla King.) pada Media Tanam dan Intensitas Naungan yang Berbeda
Abstrak: Swietenia macrophylla King. berpotensi di bidang ekonomi, kesehatan dan lingkungan, sehingga pohon ini salah satu spesies yang digunakan untuk rehabilitasi hutan. Pertumbuhan S. macrophylla dipengaruhi oleh faktor lingkungan, di antaranya kualitas media tumbuh serta intensitas naungan. Penelitian ini bertujuan untuk mendapatkan media tanam dan naungan yang tepat untuk pertumbuhan benih S. macrophylla. Penelitian ini dilaksanakan dengan menggunakan rancangan petak terbagi dengan acak kelompok. Petak utama adalah naungan menggunakan paranet yang terdiri atas 2 taraf, sedangkan anak petak adalah media tanam yang terdiri atas 5 taraf. Hasil penelitian menunjukkan adanya interaksi perlakuan media tanah mineral tanpa naungan menghasilkan tinggi tanaman dan bobot basah total tertinggi pada bibit mahoni. Perlakuan media tanah mineral dan arang sekam menghasilkan pertumbuhan terbaik pada diameter batang, jumlah dan luas daun, jumlah akar, bobot kering total dan indeks mutu bibit mahoni. Perlakuan tanpa naungan menghasilkan pertumbuhan terbaik pada diameter batang, jumlah dan luas daun, jumlah dan panjang akar, bobot kering total dan indeks mutu bibit mahoni pada umur 9 minggu setelah tanam, Swietenia macrophylla has potential in the economic, health and environmental sectors; so this tree is one of the species used for forest rehabilitation. The growth of S. macrophylla is influenced by environmental factors, including the quality of the growing media and shade intensity. This study aimed to obtain the right planting medium and shade for the growth of S. macrophylla seedlings. This research was conducted using a split-plot design with randomized groups. The main plot was shade using paranet which consists of 2 levels, while the subplot was the planting medium which consists of 5 levels. The results showed that the interaction of mineral soil media treatment without shade resulted in the highest plant height and total wet weight in mahogany seedlings. Treatment of mineral soil media and husk charcoal produced the best growth in stem diameter, number and area of leaves, number of roots, total dry weight and quality index of mahogany seedlings. Treatment without shade produced the best growth in stem diameter, number and area of leaves, number and length of roots, total dry weight and quality index of mahogany seedlings at the age of 9 weeks after planting
Keyword: intensitas naungan, media tanam, Swietenia macrophylla King.

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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