Summary
Rice blast, caused by the fungal pathogen Magnaporthe grisea, is one of the most serious diseases of rice. Here we describe the isolation and characterization of Pib, one of the rice blast resistance genes. The Pib gene was isolated by a map‐based cloning strategy. The deduced amino acid sequence of the Pib gene product contains a nucleotide binding site (NBS) and leucine‐rich repeats (LRRs); thus, Pib is a member of the NBS‐LRR class of plant disease resistance genes. Interestingly, a duplication of the kinase 1a, 2 and 3a motifs of the NBS region was found in the N‐terminal half of the Pib protein. In addition, eight cysteine residues are clustered in the middle of the LRRs, a feature which has not been reported for other R genes. Pib gene expression was induced upon altered environmental conditions, such as altered temperatures and darkness.
Peat fire in tropical peatland not only releases a large amount of carbon into the atmosphere, but also causes significant damage to peatland ecology and the landscape. It is important to understand peat fire and to establish more effective methods to control peat fire. In this paper, the results of field and laboratory research elucidate the combustion and thermal characteristics of peat fire. Field studies were carried out at 9 study plots in actual peat fire areas along the Trans Kalimantan Highway of Central Kalimantan in 2002. Laboratory analyses using a bomb calorimeter and TG-DTA were carried out to obtain low and high ignition temperatures and calorific values of various peat fire fuels. Results of field studies on weather conditions, temperatures in peat layers during fire, patterns of peat fire fronts, peat fire spreading speeds, fuel composition, moisture contents and fuel losses during fires are described in this paper. This study clarified the nature of fire movement and the smoldering process in an actual peat fire in tropical peatland. Based on our results, a more effective method for controlling peat fire can be developed. Miyanishi (2001) elucidated the processes of smoldering combustion and pyrolysis in a shallow duff layer with a numerical simulation model. The results of numerical simulation showed that both pyrolytic and oxidative degradation of duff occur down to a depth of about 1 cm and that only endothermic pyrolysis occurs below that depth due to a lack of oxygen.The results of the studies mentioned above give an excellent overview of similar aspects of peat fire processes in tropical peatland. In spite of the very different climate, peat material and social economical conditions in which peat fires occur, there are some common physical factors that play major roles in determining the incidence and propagation of peat fires. These factors are the main subject of this paper.The aim of this study is to clarify the physical aspects of peat fire characteristics in tropical peatland of Central Kalimantan, including the weather in the dry season, peat combustion properties and characteristics of fuel materials.
STUDY SITES AND METHODS
Study sitesAs shown in Fig 1, Nine study plots along the highway were selected for field observations of wildfire in peatland during the dry season in
2002.The wildfires in each plot were caused independently. The distances between plots ranged from about 1 to 30 km.The depths of the peat layer at the nine plots were about 1-3 m ( RePPProT, 1990).
The past decade marked record high air pollution episodes in Indonesia. In this study, we specifically focus on vegetation fires in Palangkaraya located near a Mega Rice Project area in Indonesia. We analyzed various gaseous air pollution data such as particulate matter (PM10), SO2, CO, O3, and NO2 study region. We also conducted elemental analysis at two different sites. Results from 2001 to 2010 suggested the longest hazardous air pollution episode during 2002 lasting about 80 days from mid-August to late-October. Maximum peak concentrations of PM10, SO2, CO, and O3 were also observed during 2002 and their values reached 1905, 85.8, 38.3, and 1003×10(-6) gm(-3) respectively. Elemental analysis showed significant increase in concentrations during 2011 and 2010. Satellite retrieved fires and weather data could explain most of the temporal variations. Our results highlight peat fires as a major contributor of photochemical smog and air pollution in the region.
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