Judul: Screening of soybean genatypes tolerance to aluminum toxicity and drought stress, and their responses to vesicular-arbuscular Mycorrhizal fungi
Abstrak: Study was conducted at Cikabayan Experimental Station of Bogor Agricultural University from February 2003 to February 2004. The objective of the study were to screen soybean genotypes tolerance to Al toxicity and drought stress, and explore its responses to vesicular-arbuscular mycorrW (VAM) fungi. Three studies, namely 1) testing of rmt growth, 2) screening of soybean genotypes tolerance to A1 toxicity and drought stress, and 3) testing of soybean responses to VAM h g r , were evaluated. Results of the study showed that soybean genotypes of Moket, B.3799, Malabar, Wiiis, Sindoro, and Slamet were tolerant while Dieng, Sinyonya, B.3780, Sicinang, B.3578, Ceneng, Epyek, MLG.3072, and Tidar were s w b l e to Al toxicity and drought stress. Increasing of soybean tolerance to A1 toxicity and drought stress was characterized by increasing of root Iength, root dry weight, shoot dry weight, proline level, and N, P, and Ca status of plant tissue. Symbioses of soybean with VAM fungi increased soybean adaptation to A1 toxicity and drought stress as shown by increasing level of root dry weight, N, P, and Ca status, and P uptake, but did not increase yield. The greatest effect of VAM occurred at 75% A1 saturation index and soil water content of 40% field capacity. Wilis was the most adapted genotype to Al toxicity and drought stress, and the most responses genotype to VAM fungi among mybean genotypes screened., Penelitian ini dilaksanakan untuk menyeleksi kedelai yang toleran terhadap cekaman Al dan kekeringan serta tanggapnya terhadap pemberian mikoriza vesicular arbuskular (MVA), yang bertempat di Kebun Percobaan Cikabayan, Institut Pertanian Bogor, mulai bulan Februari 2003 sampai Februari 2004.
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Judul: Respon pertumbuhan tanaman kedelai [Glycine max (L.) Merr.] pada kondisi kekeringan dan cekaman aluminium
Abstrak: The government has launched the soybean self sufficiency by 2014 in an effort to enough needs domestic of soybean . This will be achieved by increased productivity , expansion of cropping intensity and extension of planting area. A extension of the planting area is to utilize marginal lands. The mostly marginal lands in Indonesia is dryland acid soil and has the potential to be developed as an extension of planting area. The cultivation in dryland acid soil had several constraints, such as drought and high solubility of Al3+. The soybean response to water deficit varies depending on the genotypes, and the duration of the stress and growth phase. High solubility of Al3+ in the soil inhibits root growth. The experiment was carried out to study the growth response and the mechanisms of adaptation the soybean genotypes to drought and aluminum stress, which consists of the two stages experiments. The first stage was carried out to study the effect of genotype, drought and aluminium stress on the vegetative and generative growth and the plant roots of soybean. The second stage was carried out to study the effect of genotype, drought and aluminium stress on component crops of soybean. This experiments was conducted in Januari to November 2011, in the greenhouse Cikabayan, University Farm, IPB Darmaga Bogor. This study used a randomized complete block design, with three factors: 1) soybean genotypes (SP 30-4, Anjasmoro, PG 57-1 and Tanggamus), 2) watering interval (2 days, 6 days and 10 days, 3) the level of Al neutralization (0% neutralization and 100% neutralization). The results show that the adaptation mechanism avoidance of soybean geno types was only seen in PG57-1 on root length variables when gripped by drought. This mechanism can be seen from its root elongation when gripped by drought. The higher of value of the observed variables would be the higher the number of pods produced. It also happens to variable root dry weight and dry weight of root nodules. In general, yield components of soybean more influenced by drought stress. However, flowering only variable affected by Al stress on different genotypes.
Keyword: aluminium stress, drought stress, the mechanisms of adaptation

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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