Judul: Identification and Pathogenicity of Primary Fungi Causing Dieback Disease on Jabon Seedlings (Anthocephalus cadamba (Roxb.) Miq).
Abstrak: Jabon (Anthocephalus cadamba (Roxb.) Miq) is indigenous plant of Indonesia which is currently attracted by many people due to able provide benefits, both economical and ecological. Along with its development and cultivation, the market demand of jabon will get increase. Propagation of jabon potentially facing diseases disorders in the nursery area. This is because of available seedlings in the nursery area have the potential to be a host for the pathogens and the succulent seedling conditions are relatively vulnerable to disease attacks. The disease symptoms are often found in the jabon nursery areas and potentially leading to death of seedlings are dieback diseases. This study was conducted with the aim to isolate and identify the fungal pathogen cause of dieback diseases on jabon seedlings, determine the primary cause of dieback diseases and test the virulence levels of those isolates, and to study the mechanisms of pathogen infection and host defense mechanisms to against pathogens. The study consisted of the observation of symptoms and sampling diseased plants from the nursery locations, isolation and identification of fungi, pathogenicity assay of fungal isolates, analysis of pectinase and cellulase activities produced by fungal pathogens, and analysis of peroxidase activity on jabon. Based on observation of symptoms at the nursery sites, jabon seedlings infected dieback disease had necrotic symptoms on stems or leaves, withered or shriveled on stems. A total of 21 isolates of the fungus could be isolated from diseased plants showed necrotic symptoms at the plant tips. Identification based on morphological characters, these isolates were known as Botryodiplodia spp. as much as 9 isolates, Fusarium spp. 9 isolates, Colletotrichum sp., Curvularia sp., and Pestalotiopsis sp. each 1 isolate. Based on Koch's postulates, the fungal isolates which were pathogenic to jabon were Botryodiplodia spp., Fusarium spp., and Colletotrichum sp.. The fungus suspected as the primary cause of the dieback disease was Botryodiplodia spp. This is because of Botryodiplodia spp. isolates inoculation could produce identical symptoms with dieback symptoms that occur naturally in the field. The results of pathogenicity assay of 5 Botryodiplodia spp. isolates showed that these isolates had different degrees of pathogenicity. It could be seen from the percentage of disease severity caused. Based on Duncan's multiple interval test (α 5%) on the disease severity, could be seen that 3 of 5 Botryodiplodia spp. isolates tested were highly virulent to jabon seedlings, while the others were less virulent. The mechanisms used by Botryodiplodia spp. isolates to infect the hosts presumably performed using mechanical and biochemical forces. These were showed by the appearance of necrotic symptoms on unwounded inoculation sites and the pectinase and cellulase activities detectable from Botryodiplodia spp. isolates cultured in CMS (Corn Meal Sand) media. Pectinase activity produced by Botryodiplodia spp. isolates was ranging from 18.131 to 26.083 U ml-1, whereas cellulase from 0.014 to 0.023 U ml-1. The defense mechanism of jabon plant against pathogen infection, one of them was vii performed by produce peroxidase which plays role of lignification process and secondary metabolite compound formation. Peroxidase activity detectable on the jabon plants after pathogen inoculation was ranging from 0.0006 to 0.0012
Keyword: Botryodiplodia spp., Fusarium spp., Koch’s postulate, necrotic, nursery

Judul: Resistensi Bibit Jabon Putih dan Merah (Anthocephalus spp.) terhadap Serangan Botryodiplodia theobromae Penyebab Penyakit Mati Pucuk
Abstrak: White and red jabon seedlings are very popular to nurserier, because of the benefits and can improve the economic. The main problem in nurseries are insects and diseases attack. One of the diseases is dieback disease. Dieback disease is caused by B. theobromae, that can make the seedlings death. These pathogens can attack passively and actively. Every plant has a mechanism of resistance to pathogen attack, either structural or biochemical, before and after attacked. This research aimed: (1) to test B. theobromae attacked with non wounded and wounded stem infection methods in jabons; (2) to study the structural and biochemical resistance of jabons to B. theobromae attacked; (3) to study the interaction between the species of jabons and stem infection methods in jabons to the resistance of jabon seedlings; (4) to obtain the most resistance species of jabons to B. theobromae attacked. This research used factorial completely randomized design that combined the species of jabons and stem infection methods in seedling. The structural resistance was done with studying the microscopy of infected and non infected jabon used scanning electron microscope. The biochemical resistance was done with studying the chemical compound of Jabons used phytochemistry analysis. The disease incidency of red jabon seedlings with non wounded stem infection methods were 80%, that were wider than white jabon seedlings were 30%. The disease severity of red jabon seedlings with non wounded stem infection methods were 16%, that were worse than white jabon seedlings were 12%. The response of the species of jabons and non wounded stem infection method for the disease severity showed the same severity. The disease incidency of red and white jabon seedlings with wounded stem infection methods were 100%. The disease severity of white jabon seedlings with wounded stem infection methods were 62%, that were worse than red jabon seedlings were 38%. The response of the species of jabons and wounded stem infection method for the disease incidency showed the same width high, but, the disease severity of white jabon seedlings were worse than red jabon seedlings. The incidency and the severity of disease in jabons with wounded stem infection methods were wider and worse than jabons with non wounded stem infection methods. The white jabon seedlings just had the necrotic resistance as the structural resistance after pathogen attacked. Before and after pathogen attacked of red jabon seedlings, structural resistance were showed with found the structure of trychomaes on the epidermis and the necrotic resistance. The biochemical resistance before pathogen attacked of red jabon seedlings were found secondary metabolites, aspecially, triterpenoid and steroid, but, for white jabon seedlings were just found steroid. After pathogen attacked of red jabon seedlings, the biochemical resistance were showed with found the increase in the content of phenol hydroquinon, tannin and the fixed of flavanoid, but, the white jabon seedlings had the increase in the content of flavanoid, tannin and the decrease of phenol hydroquinon.
Keyword: biochemical resistance, disease incidency, disease severity, stem infection methods, structural resistance

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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