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: Sago (Metroxylon spp.) Propagation with Ex vitro (Polybag and Raft seedlings) and In vitro through Tissue Culture
Abstrak: Present studies were carried out to determine the effect of auxin, weight of sucker, on root induction and growth variables in nursery of sago seedlings. The research were used Darmaga accession (spineless). For this purpose some parameters were studied after treating suckers with some auxin concentrations, i.e. control (without growth regulators/ 0 mM), 7.40 mM naphthalene acetic acid (NAA), 7.40 mM indole butyric acid (IBA), and 7.40 mM commercial auxin, and weight of sucker i.e 500-999 g, 1 000-1 499 g, and 1 500-2 000 g, with polybag and raft nursery. The treatments were applied by one method (quick dip) and the treated suckers were submerged 30 minutes in pesticides before. This research was conducted at Cikarawang, Dramaga, Bogor, West Java and Physiology and Chromatoghraphy Laboratory, Department of Agronomy and Horticulture, Bogor Agricultural University, from July 2012 to Mart 2013. The result from polybag nursery showed that suckers weight 1 000-1 499 g and 1 500-2 000 g were not significantly different on polibag nursery. The result of without auxin, IBA, NAA, and commercial auxin treatments for survival rate were 52%, 70%, 62%, 53% respectively. Increasing percentage of starch content in line with the increasing weight of sucker. On the raft nursery,treatment of NAA showed significantly inhibit seedling growth, as indicated by reduction the 1st rachis height and amount of 1st rachis leaflets compare with kontrol and commercial auxin. Treatments of auxin did not give significantly different on some variables (number of primary roots, number of aerenchym roots, and the length of root. Survival rate percentage of seedlings were obtained 65% (for both weight sucker 1 000 – 1 499 g and 1 500-2 000 g) on 4 month after nursery (MAN), while the sucker weights 500-999 g produced survival rate percentage is lower than 40%. Either polybag and raft nurseries, showed that there were significantly different to height of abnormal rachis, number of leaflets of abnormal rachis, number of leaflets of 1st rachis, diameter of 1st rachis, number of primary roots, and aerenchyma roots. Both of nursery techniques were not significantly different on percentage of survival rate seedlings. Rachis diameter in raft nursery was significantly higher than in polybag nursery, 5.9 cm and 1.2 cm respectively. The number of primary roots at polybag higher than at raft nursery.Combination treatments of without auxin and suckerr weight 500-999 g has a number of primary roots 5.5 at polibag nursery and 0.13 at raft nursery. Combination treatments of 7.04 mM IBA, without auxin auxin and suckerr weight 1000-1499 g have a number of primary roots 9.6 and 18.2 at polibag nursery and 0.19 and 0.73 at raft nursery, respectively. Combination treatments of without auxin, 7.04 mM IBA, 7.04 AK and suckerr weight 1500-2000 g have a number of primary roots 7.6, 6.8, and 8.8 at polibag nursery and 0.31, 0.29, dan 0.33 at raft nursery, respectively.But, a number of aerenchyma roots at raft nursery were higher than at polybag nursery i.e. 7.08 dan 1, respectively. In vitro culture for sago palm from shoot tip and young leaf explants were conducted. This study was carried
Keyword: root induction, primary roots, aerenchyma roots, sucker, auxin

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.
Keyword: