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.
Keyword: 

Judul: Morphology and physiology adaptation of some soybean genotypes [Glycine max (L.) Merr] to drought and aluminium stress
Abstrak: The experiment was carried out to study the effect of drought and aluminium (Al) stress on morphological, physiological and yield component of tolerant and sensitive soybean genotypes. This experiment was conduct on two phase. At first was on June to September 2010 and use a randomized block design (RBD), which consists of three factors: 1) soybean genotypes (Anjasmoro, SC 56-3, PG 57-1, SP 30-4 and Tanggamus), 2) soil water content (100% , 75% and 50% field capacity), 3) the level of Al neutralization (100% neutralization, 75% neutralization and 50% neutralization). Genetically there were differences on plant height, number of leaves, leaves dry weight and root dry weight. Drought decreased plant height, number of leaves, leaves, root and nodules dry weight in most all genotypes. Stems dry weight and number of branches were affected by interact between genotype and water level. Drought and Al stress decreased stems dry weight mostly on all genotypes. On physiological parameter, leaves color index (LCI) and chlorophyll b content, were affected by genotypes. Otherwise, drought increased LCI, chlorophyll a and b content. Al stress decreased chlorophyll b content. The yield component of all genotypes were variety depend on each water level and Al neutralization. Water use efficiency (WUE) on water level 100% field capacity and neutralization Al 100% were optimal condition on most genotype. There were 10 parameters have positive correlated with yield, there are: plant height, number of leaves, number of branch, leaves dry weight, stems dry weight, roots dry weight, pods dry weight, number of pods, number of full pods and pods weight. The result of sensitivity index analysis on 10 variables were classified PG 57-1 as tolerant and SP 30-4 as sensitive genotype to drought and Al stress. The second phase axperiment was conduct on November 2010 to February 2011, use a randomized block design (RBD), which consists of three factors: 1) two soybean genotypes (PG 57-1 and SP 30-4), 2) two level of soil water content (75% and 50% field capacity), 3) the level of Al neutralization (100% neutralization, 75% neutralization and 50% neutralization). There were no differences between tolerant and sensitive genotype on proline content, net assimilation rate (NAR) and relative growth rate (RGR). But on tolerant genotype, nodules dry weight were higher than the sensitive one.
Keyword: 

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.
Keyword: