Soil water content and water balance in rainfed fields in Northeast Thailand

Northeast Thailand has a semi-humid tropical climate which is characterized by dry and rainy seasons. In order to stabilize crop production, it may be necessary to develop new water resources, such as soil moisture and groundwater, instead of rainfed resources. This is because rainfed agriculture has already been unsuccessfully tried in many areas of this region. In this study, we investigate the soil water content in rainfed fields in Khon Kaen in Northeast Thailand, where rice and sugarcane were planted, over a 1-year period that contained both dry and rainy seasons, and estimate the actual evapotranspiration (ET_a) using micrometeorological data. In addition, we assess the water balance from the results of the soil water content investigation and the actual evapotranspiration. Although the soil water content at depths above 0.6 m in both the lower and the sloping fields gradually decreased during the dry season, the soil water content at a depth of 1.0 m was under almost constant wet conditions. Two-dimensional profiles of the soil water content demonstrated that at the end of the dry season, the soil layers below a depth of 0.4 m showed a soil water content of more than 0.10-0.15 m³ m⁻³, thus suggesting that water was supplied to the sugarcane from those layers. The range in ET_a rates was almost the same as that in the previous study. The average ET_a rates were 3.7 mm d⁻¹ for the lower field and 4.2 mm d⁻¹ for the sloping field. In the dry season, an upward water flow of 373 mm (equivalent to a flux of 1.9 mm d⁻¹) was estimated from outside the profile. The source of this upward water flow was the sandy clay (SC) layer below a depth of 1 m. It was this soil water supply from the SC layer that allowed the sugarcane to grow without irrigation.     

Systemic necrosis in tomato induced by a Japanese isolate of rehmannia mosaic virus in a temperature-sensitive manner

The Japanese isolate of rehmannia mosaic virus (ReMV-J) was initially isolated from chilli pepper in Japan. The leaves of diseased chilli pepper plants, which hold no tobamovirus-resistance genes, have mosaic symptoms. As the symptoms progress, the infected plants develop prominent leaf necrosis and severe leaf fall, followed by stem necrosis and fruit distortion. Additionally, ReMV-J systematically infects tomato and this reportedly leads to mottle in tomato when incubated at 20 °C. This study found that ReMV-J induces systemic necrosis of tomato – except for cultivar Micro-Tom – when incubated at 25 °C. To determine the virus factor involved in the induction of temperature-sensitive systemic necrosis on tomato, intergenic recombinants between ReMV-J and tomato mosaic virus were constructed. All recombinant viruses systemically infected tomato similar to ReMV-J. Recombinant viruses with the movement protein (MP) gene of ReMV-J induced systemic necrosis on tomato. Incubation at 20 °C significantly reduced the ability of recombinant viruses with the MP gene of ReMV-J to induce systemic necrosis. Thus, the ReMV-J MP gene is involved in the temperature-sensitive induction of systemic necrosis on most tomato cultivars tested. This study is the first to report the involvement of the MP gene in temperature-sensitive induction of systemic necrosis by tobamovirus on tobamovirus-susceptible tomato.     

Seasonal characteristics of surface water quality in the wastewater catchment system of an urbanizing basin

Vientiane, Lao PDR, has been subject to extensive and ongoing urbanization plans, including development of natural marshes and residentialization of paddy fields into suburban areas, despite natural marshes playing a vital role in treating wastewater from urban areas. Therefore, it is important to understand the current situation regarding the nutrient balance in these natural wastewater treatment systems to predict future conditions and design appropriate measures against water quality deterioration. However, limited data are available in Vientiane on the hydrological characteristics of water and nutrient runoff that flow into marshes through drainage canals. In this study, we conducted a periodic survey of drainage canals and Mak Hiao River in the wastewater catchment system surrounding Vientiane during the rainy and dry seasons. We monitored the discharge of surface water at 21 observation sites and analyzed water quality of nitrogen, phosphorus, and total organic carbon. These observations revealed that the concentrations of dissolved nitrogen and phosphorus were significantly higher at sites in urban areas, followed by sites in the main river basin and those in agricultural areas. Dissolved nitrogen and phosphorus concentrations varied with runoff discharge, especially in urban and river basin sites, with lower concentrations in the rainy season and higher concentrations in the dry season. On the other hand, we found no significant differences between the rainy and dry seasons in nutrient concentrations in the agricultural basin. Finally, we proposed measures to counteract the deterioration of water quality during dry seasons and simulated the impact of these measures.     

Combined on-farm effect of plot size and sorghum genotype on sorghum panicle-feeding bug infestation in Mali

The reaction of four sorghum cultivars to panicle-feeding bugs was assessed in small (15 m²) and large (0.5–1.0 ha) plots for 2 years in three villages of the Kolokani region (Mali). The aim was to explain the somewhat contradictory earlier observations of pest infestation and damage in small experimental plots (on-station and on-farm) as well as in farmers’ field surveys. Irrespective of the plot size, the local guinea sorghum cultivar Bibalawili was consistently the least infested and damaged, followed by bug-resistant compact-headed cv Malisor 84-7, whereas the improved caudatum cultivar Gadiabani, which had been disseminated for nearly a decade in the region, and the improved hybrid ICSH 89002, were the most heavily damaged. When located along the border of large plots of a susceptible cultivar, small plots of the four cultivars overall were less infested and damaged than when located along the border of plots of resistant cultivars. However, they were more infested and damaged when located in the centre of large plots of susceptible cultivars than when they were in the centre of resistant cultivar plots. In large plots, bug populations and damage decreased from the border to the centre. These results suggest that, in addition to the mere plot size, plant breeders should take the genotypic environment of their experimental plots into account, namely the vicinity of large plots of pest-susceptible or -resistant cultivars, and the position of the test plots (border or centre) relative to these large plots.     

Extensive Screening for Plant Foodstuffs in Okinawa,Japan with Anti-Obese Activity on Adipocytes <Emphasis Type="Italic">In Vitro</Emphasis>

To search for plant foodstuffs with potent anti-obese activity, we conducted a large scale screening based on the inhibitory activity on adipogenesis and the facilitating activity on adipolysis in vitro. That is, inhibition of intracellular lipid accumulation and facilitation of lipid degradation in 3T3-L1 adipocytes were extensively screened from ethanol and hexane extracts of approximately 100 kinds of plant foodstuffs marketed in Okinawa prefecture, which has been famous for the highest prevalence of exceptionally long-lived individuals in the world. Among them thirty one foodstuffs showed potent inhibitory activity on intracellular lipid accumulation in 3T3-L1 adipocytes, whereas only four foodstuffs showed clear facilitating effect on lipid degradation in 3T3-L1 adipocytes. Although further study to examine the in vivo effects on adipogenesis and adipolysis is required, this is the first study to investigate anti-obese characteristics of wide range of traditional Okinawa foodstuffs so that the results give useful information to take another look at Okinawa food culture.     

Seasonal variations in the cooling effect of urban green areas on surrounding urban areas

We measured air temperature in an urban green area that includes forest and grassland and in the surrounding urban area for a full year in Nagoya, central Japan, to elucidate seasonal variations of the difference in air temperature between urban and green areas. We determined the range of the “cool-island” effect as well as the relationship between vegetation cover and air temperature throughout the year. The temperature difference between urban and green areas was large in summer and small in winter. The maximum air temperature difference was 1.9 °C in July 2007, and the minimum was ?0.3 °C in March 2004. The difference was larger during the day than during the night in summer, whereas in winter the opposite relationship was true. However, winter diurnal variation was not particularly noticeable, a behaviour thought to be related to reduced shading by deciduous trees in the green area. During the night, the cooling effect of the green area reached 200–300  m into the urban area. During the day, the cooling effect between August and October 2006 exceeded 300 m and varied widely, although there was no correlation beyond 500 m. The correlation between air temperature and forest-cover ratio within a radius of 200 m from each measurement site was significant from 16:00 to 19:00. There was also a correlation during the night; this correlation was weakest in the early morning. The effect of the forest-cover ratio on air temperature was most pronounced in August 2006 and June 2007.     

Long-term treatment effects of Pueraria mirifica phytoestrogens on parathyroid hormone and calcium levels in aged menopausal cynomolgus monkeys

To determine the effect of Pueraria mirifica (PM) on serum parathyroid hormone (PTH) and calcium levels on aged menopausal monkeys (Macaca fascicularis), subjects were treated with 10, 100, or 1,000 mg/day of PM. Blood samples were collected every 5 days for 30, 90, and 60 days during pre-treatment, treatment, and post-treatment periods, respectively. Sera were assayed for PTH, estradiol, and calcium levels. PM-1,000 had the strongest effect on the decrease in PTH (0.001相似文献   

Effect of linoleic acid-albumin on post-thaw survival of in vitro-produced bovine embryos at the 16-cell stage

The effect of addition of linoleic acid-albumin (LAA) to culture medium before freezing on the survival rate of bovine 16-cell embryos after freezing-thawing was investigated. Embryos were incubated in CR1aa containing LAA (0.25 mg/ml) for 4 days after insemination. A conventional slow cooling method was used, in which embryos were cooled at a rate of 0.3 degrees C/min to -30 degrees C in medium supplemented with 1.5 M ethylene glycol and 0.2 M trehalose. The developmental rate to the blastocyst stage of thawed embryos that had been cultured with LAA-containing medium before freezing was higher than that of these cultured without LAA (P<0.05). However, with fresh, non-frozen, embryos that were incubated under the same culture conditions (with and without LAA), no such difference was found.