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Leong Shing Tet Muttamara S. Laortanakul Preecha 《Water, air, and soil pollution》2001,131(1-4):41-60
This study investigated the relationship between exhaust emission from motorcycles and ambient air quality in Bangkok Metropolitan Region (BMR). The test result revealed that averagepollutant concentrations of the test motorcycles in terms of hydrocarbon, carbon monoxide and nitrogen dioxide were 8.38, 16.69 and 0.04 g km-1, respectively. The finding also indicated that two-stroke motorcycles emitted 1.5 and 5 times more carbon monoxide and hydrocarbon emission, respectively perkilometer driven than do four-stroke motorcycles. Four air sampling stations were strategically established to evaluate the air pollution problems in Bangkok arising from vehicle exhaust emission. Investigation was carried out to determine the correlation between average air pollutant concentration with different traffic configuration in each traffic zone of Bangkok Metropolitan Region (BMA) during peak/non peak hours, day/night times and weekday/weekend. The average concentrationsof PM10 particulate matter, carbon monoxide, nitrogen dioxide and sulphur dioxide in Bangkok street air were found tobe 84.33 μg m-3 (24 hr ave.), 7.05 mg m-3 (8 hr ave.), 56.74 μg m-3 (1 hr ave.) and 9.60 μg m-3 (24 hr ave.), respectively. 相似文献
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Prathepha P 《Pakistan journal of biological sciences: PJBS》2008,11(1):26-33
The two wild rice species, Oryza rufipogon and O. nivara, which inhabit Thailand and the Lao PDR, are threatened with the loss of their natural habitats. The losses are primarily attributable to human intervention. Before this process advances, it is crucial to obtain basic information on the genetic variations of these species, so important knowledge about the current status of genetic variability. In this study, genetic variation within and between fourteen natural populations of the two populations from Thailand and Lao PDR was investigated at the DNA level by analysis of Polymerase Chain Reaction (PCR) mediate molecular markers. The results illustrated that wild rice from Thailand carried deletion (D) type ORF 100, but deletion and non-deletion type (ND) were found in wild rice samples from the Lao PDR. Five different plastid subtypes (7C7A, 6C8A, 7C6A, 6C7A and 9C7A) were found in the collected samples. Both polymorphism and pattern of distribution of p-SINE1-r2 in the two wild rice species were found among the populations. These data indicated that genetic variation existed in these natural populations of wild rice, suggesting that the strategies should be developed that are conducive to the conservation of wild rice in its natural environment. 相似文献
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Preecha Prathepha 《Genetic Resources and Crop Evolution》2009,56(1):13-18
The Asian cultivated rice, Oryza sativa L. (spp. indica or japonica), is assumed to have originated from one or both of the two wild Asian species, O. rufipogon Griff. and O. nivara Sharma and Shastry. They occur throughout the monsoon Asia and west Oceania. Fragrance is the most important trait among
the domesticated characters of basmati and jasmine rice of Asia. The gene for fragrance in a scented rice shows the presence
of a mutated portion (i.e., an eight base pair deletion in exon 7) that result in its loss of fragrance. In the present study,
229 wild rice O. rufipogon accessions were genotyped for this locus using a PCR assay. The wild rice species contained the mutated allele of the fgr
gene at a low frequencies of 0.23. The surveyed populations were in Hardy–Weinberg equilibrium. This observation supports
the hypothesis that the allele for fragrance was already present in the wild rice, and that this trait appeared in scented
rice cultivars because of selection by the farmers of genotypes possessing this character during the process of domestication. 相似文献
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Eighty-two varieties of rice from different regions in Thailand were selected to explore the Waxy (Wx)gene diversity and indica-japonica differentiation of chloroplast DNA. A comparison of the 5 splice site in the first intron was made between glutinous and nonglutinous rice. It revealed that non-glutinous with low-amylose content and glutinous rice were characterized as the Wxb allele based on the G-to-T base substitution, whereas non-glutinous rice with intermediate and high amylose carried the Wxa allele. Four Wx microsatellite alleles, (CT)n repeat, (n = 16,17,18 and 19) were found in glutinous rice. In contrast, non-glutinous rice showed five Wx microsatellite alleles (n = 11, 16, 17, 18 and 19). The (CT)17 allele was prominent allele in Thai population, while the (CT)11 allele was found only in intermediate and high amylose rice varieties from southern Thailand. Almost all of upland rice grown by various ethnic groups in northern Thailand were characterized as japonica type based on their having the PstI-12 fragment in their cpDNA, whereas most of rainfed lowland varieties from other regions of Thailand were indica. This exploration of DNA-based genetic markers is important, as it enhances our ability to describe and manipulate sources of genetic variation for rice breeding programs. 相似文献
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Parkpian Preeda Leong Shing Tet Laortanakul Preecha Torotoro Josephine L. 《Water, air, and soil pollution》2002,139(1-4):43-60
This study was conducted to assess the potential of Bangkoksewage sludge for amendment of saline and acidic soil withrespect to heavy metal mobilization. Experiments were carriedout at six levels of salinity (with electrical conductivityvalues of 2, 4, 8, 19, 31 and 42 dS m-1) and two levels ofacidity (with pH values of 5 and 6). A pure sludge sample was used as a control system. Subsamples were collected andanalyzed for total and bioavailable heavy metals. Three sets ofsoil-sludge mixture were prepared using different weight ratio(1:1, 4:1 and 10:1) to simulate the conditions in the field withsludge-amended soil. Samples of soil-sludge mixture were incubated for 4 weeks to stabilize organic substances. Themobility and concentration of bioavailable heavy metal invarying soil-sludge mixture ratio with different electricalconductivity (EC) values were evaluated with the use of DTPA(diethylenetriamine pentaacetric acid) extraction techniques.Pure saline soil sample from Sakhon Nakhon (North-eastern partof Thailand) was used of salt-heavy metal interactions on thegermination percentage in soil mixed with sludge and to screencrops or varieties for their tolerances to soil salinity. Seventypes of seeds – mung bean, corn, soybean, tomato, stringbean, sunflower and marigol – were planted in each of the threesoil-sludge mixtures (1:1, 4:1 and 10:1) with different salinitylevels. Seedlings were monitored by counting the number of seeds thatare germinated and seed germination percentage can be used as anindicator for the level of salinity unsuitable for plant growth. 相似文献
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Adisakwattana S Moonsan P Yibchok-Anun S 《Journal of agricultural and food chemistry》2008,56(17):7838-7844
Cinnamic acid derivatives are naturally occurring substances found in fruits, vegetables, and flowers and are consumed as dietary phenolic compounds. In the present study, cinnamic acid and its derivatives were evaluated for insulin secreting activity in perfused rat pancreas and pancreatic beta-cells (INS-1) as well as an increase in [Ca(2+)]i in vitro. The presence of m-hydroxy or p-methoxy residues on cinnamic acid was a significantly important substituent as an effective insulin releasing agent. The introduction of p-hydroxy and m-methoxy-substituted groups in cinnamic acid structure (ferulic acid) displayed the most potent insulin secreting agent among those of cinnamic acid derivatives. In particular, the stimulatory insulin secreting activities of test compounds were associated with a rise of [Ca(2+)]i in INS-1. In perfused rat pancreas, m-hydroxycinnamic acid, p-methoxycinnamic acid, and ferulic acid (100 microM) significantly stimulated insulin secretion during 10 min of administration. The onset time of insulin secretion of those compounds was less than 1 min and reached its peak at 4 min that was about 2.8-, 3.3-, and 3.4-fold of the baseline level, respectively. Intravenous administration of p-methoxycinnamic acid and ferulic acid (5 mg/kg) significantly decreased plasma glucose and increased insulin concentration in normal rats and maintained its level for 15 min until the end of experiment. Meanwhile, m-hydroxycinnamic acid induced a significant lowering of plasma glucose after 6 min, but the effects were transient with plasma glucose concentration, rapidly returning to basal levels. Our findings suggested that p-methoxycinnamic acid and ferulic acid may be beneficial for the treatment of diabetes mellitus because they regulated blood glucose level by stimulating insulin secretion from pancreatic beta-cells. 相似文献
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