Judul: Pembentukan akar tanaman hias Cordyline fruticosa 'Hawaian flag' secara ex vitro
Abstrak: Cordyline sp. is a woody ornamental monocot, belongs to Asparagaceae family. The use of in vitro culture can support the propagation of Cordyline sp. to produce more planlets in a shorter time. In vitro root system of plantlets of Cordyline fruticosa 'Hawaian flag' is usually very weak and easily removed when washed in running tap water. Therefore, planlets were grown without roots in vitro and rooting of planlets was conducted during acclimatization period. This research was aimed to determine the influence of various types and concentrations of auxin on rooting and growth of Cordyline fruticosa plantlets during the acclimatization period. Type of auxin hormones i.e. IAA, IBA and NAA and concentrations at 20 μM, 100 μM and 500 μM did not significantly affect the rooting and growth of Cordyline fruticosa. Having compared all the treatments, it can be concluded that IAA 100 μM was the better one in inducing roots of the planlets in term of numbers of secondary roots and the growth of the shoots. Ex vitro rooting can also be done without hormones with the same results as with auxins was used in this research.
Keyword: Bogor Agricultural University, acclimatization, ex vitro rooting, Cordyline fruticosa, auxin

Judul: Morphological Study and Cutting Propagation of Various Hoya Species
Abstrak: Produksi bibit melalui stek batang dapat dibantu oleh Rootone-F dan IBA untuk menginduksi perakaran. Penelitian ini bertujuan mendeskripsikan morfologi tiga spesies Hoya berdasarkan keragaman daun, bunga, dan pertumbuhan tanaman dan mengetahui pengaruh Rootone-F dan IBA terhadap perbanyakan bibit melalui stek tiga spesies Hoya. Penelitian ini dilakukan di Kebun Percobaan Leuwikopo, Institut Pertanian Bogor. Percobaan dilaksanakan pada Januari-Mei 2024 disusun dalam Rancangan Kelompok Lengkap (RKLT), dengan tiga spesies (Hoya latifolia, Hoya nabawanensis, dan Hoya diversifolia) dan dua hormon perakaran (kontrol, Rootone-F dan IBA). Terdapat 2 ulangan yang masing-masing terdiri atas 5 stek. Hasil penelitian menunjukkan bahwa ketiga spesies memiliki kemiripan pada warna daun tua, bentuk corona (mahkota dalam) dan perbedaan morfologi pada organ daun, batang dan bunga. Persentase hidup terbaik pada stek Hoya dicapai dengan perlakuan kontrol dan Rootone-F. Perakaran stek Hoya tumbuh paling cepat dengan penggunaan Rootone-F, menunjukkan Rootone-F mampu menginduksi pembentukan akar lebih baik dibandingkan IBA. Jumlah daun, jumlah tunas, dan jumlah akar udara hanya dipengaruhi oleh spesies. IBA dan Rootone-F hanya memengaruhi panjang tunas pada awal pertumbuhan. Tidak ada interaksi antara faktor spesies dan ZPT. Secara keseluruhan, penelitian ini mengungkap bahwa Rootone-F memiliki potensi sebagai ZPT yang efektif untuk meningkatkan persentase hidup dan laju pertumbuhan akar stek Hoya., Seedling production through stem cuttings can be assisted by Rootone-F and IBA to induce rooting. This research aims to describe the morphology of three Hoya species based on leaf, flower, and plant growth diversity and to determine the effects of Rootone-F and IBA on the propagation of seedlings through cuttings of three Hoya species. The research was conducted at Leuwikopo, Bogor Agricultural University. The experiment was carried out from January to May 2024, organized in a Complete Randomized Block Design (RKLT), with three species (Hoya latifolia, Hoya nabawanensis, and Hoya diversifolia) and two rooting hormones (control, Rootone-F, and IBA). There were 2 replicates, each consisting of 5 cuttings. The results showed that the three species had similarities in mature leaf color, corona (inner crown) shape, and morphological differences in leaf, stem, and flower organs. The best survival percentage for Hoya cuttings was achieved with control and Rootone-F treatments. Rooting in Hoya cuttings grew the fastest with the use of Rootone-F, indicating that Rootone-F can induce root formation better than IBA. Leaf number, shoot number, and aerial root number were only affected by species. IBA and Rootone-F only affected shoot length at the early growth stage. There was no interaction between species and plant growth regulator (PGR) factors. Overall, this study reveals that Rootone-F has the potential to be an effective PGR to improve the survival percentage and root growth rate of Hoya cuttings.
Keyword: auksin, IBA, auxin, hoya, Rootone-F, rooting

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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