The objectives of this study are to propose a remotely measurable plant transpiration transfer coefficient (h_at) and to verify its characteristics under various environmental conditions. The h_at is defined as (T_c - T_a) / (T_p - T_a), where T_c, T_p, and T_a are the temperatures of the canopy, a non-transpiring canopy, and air, respectively. Theoretically, h_at ≦ 1, and determines transpiration from its minimum value (zero) to its maximum value (potential transpiration rate). Five experiments were conducted between 1994 and 1999 to verify the characteristics of h_at, using 3 plant species (sorghum, tomato and melon). Theoretical validation showed that the proposed model agreed well with conventional models. Experimental results showed that the h_at value was approximately equal to the value of the ratio of sensible heat fluxes (H/H_p), and the slope of the regression line between them was close to 1, the intercept was close to 0, and the regression coefficient was r² = 0.70. In addition, h_at was not only an indicator of the water status in the plant root zone, but also an indicator of atmospheric variables. Under waterstressed conditions, h_at was affected mainly by the water status in the plant root zone. Therefore, h_at can be used as an indicator of plant water stress. The main advantages are that h_at can be easily measured and applied under various conditions. Due to its simplicity, h_at is a suitable coefficient for analyzing the process of transpiration and for determining the transpiration rate.

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Effect of sesamin, a sesame lignan, on the hepatic fatty acid metabolism was examined in the rat. Increase of the dietary level of sesamin progressively increased the mitochondrial and peroxisomal fatty acid oxidation rate. Mitochondrial activity almost doubled in rats fed a 0.5% sesamin diet. Peroxisomal activity became more than 10 times higher in rats fed a 0.5% sesamin diet, compared to those fed a sesamin-free diet. Dietary sesamin also markedly increased the hepatic activity and mRNA levels of various fatty acid oxidation enzymes. In contrast, dietary sesamin decreased the hepatic activity and mRNA abundance of lipogenic enzymes. This was associated with the down-regulation of sterol regulatory element-binding protein-1, a transcriptional factor that regulates the lipogenic enzyme gene expression. Dietary sesamin significantly decreased the triacylglycerol secretion accompanying the increase in ketone body production by the perfused rat liver. It is apparent that sesamin affects the fatty acid metabolism and lipoprotein production in the liver, and hence lowers the serum lipid levels. We also developed several sesame lines with seeds containing sesamin and sesamolin at twice the concentration of conventional cultivars. Compared to a conventional cultivar, these lignan-rich sesame seeds increased the hepatic fatty acid oxidation rate and lowered the serum triacylglycerol level in the rat. Therefore, it is considered that enrichment of the lignans potentiates the characteristics of sesame in improving human health.

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Some diets have been shown to be correlated with the development and progression of cancer. In contrast, many kinds of foods are expected to prevent the development and progression of cancer. To identify such cancer-preventive food components and elucidate their cancer-preventive functions, we investigated important anti-cancer effects, that is, growth-inhibitory and apoptosis-inducing effects of some food and food components on cancer cells. Among the vegetables studied, bitter gourd was the most effective in inhibiting the growth of HL60 human leukemia cells. Bitter gourd extract induced apoptosis in the cells. The bitter gourd extract also inhibited growth and induced apoptosis in B16 mouse melanoma 4A5 cells, whereas it inhibited the growth of BALBc/3T3 mouse fibroblast cells only to a small extent. Berries are rich sources of the naturally occurring phenolic pigments anthocyanins, which show a potent antioxidant activity. Bilberry ethanol extract strongly inhibited the growth of HL60 and HCT116 human colon carcinoma cells, and also induced apoptosis in HL60 cells but not in HCT116 cells. Of the berry extracts tested, that from bilberry contained the largest amount of phenolic compounds, including anthocyanins, and exhibited the highest DPPH radical-scavenging activity. The anthocyanidins, delphinidin and malvidin, inhibited cell growth and induced apoptosis in HL60 cells. Delphinidin, but not malvidin inhibited the HCT116 cell growth. These effects of food components probably contribute to cancer prevention.

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Studies on the physiological functionality of purple-fleshed sweet potatoes and their dominant anthocyanin pigments are described. The purple-fleshed sweet potato cultivar ‘Ayamurasaki’ contained anthocyanins, which consisted of mono- or di-acylated forms of cyanidin (YGM-1a, -1b, -2 and -3) and peonidin (YGM-4b, -5a, -5b and -6). It was also rich in anthocyanins with peonidin aglycon. The ‘Ayamurasaki’ extract and the purified YGM exhibited multiple physiological functions such as radical-scavenging, antimutagenic, angiotensin I-converting enzyme-inhibitory, and α-glucosidase-inhibitory activities in vitro. Moreover, they also showed an ameliorative effect on carbon tetrachloride-induced liver injury and decreased postprandial blood glucose levels in rats. In addition, their role in restoring the liver function and blood pressure levels to normal in volunteers with impaired hepatic function and/or hypertension was also confirmed. The acylated anthocyanins, which were the major radical scavengers in ‘Ayamurasaki’, were directly absorbed into the blood stream of rats and were present as intact acylated forms in the plasma, and could also enhance the plasma antioxidative capacity. Based on these evidences, the purple-fleshed sweet potato can be recommended as a superior source for the production of foods with health benefits. Some foods and beverages in Japan that utilize these characteristics of anthocyanin pigments are also introduced in this paper.

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Prevention of precocious bolting, i.e. stem elongation accompanied by flowering, in Japanese radish (Raphanus sativus L.) was attempted using a foliar spray of uniconazole, a gibberellin biosynthesis inhibitor. At first, appropriate conditions for the prevention of precocious bolting, such as uniconazole concentration, extent of vernalization and floral stage were investigated using an incubator. Higher uniconazole concentration (≧17 µM) and shorter duration of vernalization were found to be desirable. For effective retardation of bolting and flowering, uniconazole should be applied before floral evocation. Based on these results, uniconazole was applied to cv. ‘Taibyo-sobutori’ and cv. ‘Oshin’ during winter and spring cultivation. Bolting and flowering were delayed up to 10 and 6 days, respectively, when the uniconazole (17 µM) treatment was administered before floral evocation.

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Given the demand by farmers for early budding cultivars in tea, this study was carried out to select moderately early lines without frost damage, as well as lines showing rapid growth after flushing among 1,300 tea (Camellia sinensis) accessions preserved at the Makurazaki Station of the National Institute of Vegetable and Tea Science, Japan. A model for flushing and leaf opening [y = (ax+b)^0.5, y: number of open leaves, x: effective accumulated temperature calculated by integrating values of temperatures being 10°C below the daily minimum air temperature since the date of autumn skiffing and a,b: parameters] was developed before the selection. For the selection, the estimated parameters were used as indicators of the flushing temperature and opening speed of tea leaves. As a result, 120 moderately early lines, 79 rapidly growing lines and 12 lines (parameter a>0.5, x₀ = 145–150°C) with both characteristics were selected. Furthermore, Taiwan-yamacha which showed extremely late flushing characteristics, accounted for 44 of the 68 late flushing lines and is expected to be used as breeding material to extend the harvesting period for the first crop.

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As part of the research aimed at elucidating the cause of low tea yields in the first crop in southern Japan, the relation of climatic conditions to winter bud dormancy was investigated using mature ‘Yabukita’ (Camellia sinensis (L.) O. Kuntze) plants at the Makurazaki Station (N 31° 16.1´) of the National Institute of Vegetable and Tea Science (NIVTS), Japan, as a model. The number of days required for flushing (RDF), when winter tea branches were kept under optimal artificial conditions (25°C, 14-hour daylength and 80% relative humidity), was used as an indicator for expressing the degree of winter bud dormancy. RDF was well predicted by the model [–aT–bD+c (T: mean temperature, D: daylength and a,b,c: parameters)] with the lowest standard error (1.71) and the lowest value of Akaike’s Information Criterion (AIC = 124.06). The simulation of winter bud dormancy indicated that tea grown in Okinawa located in the southernmost region of Japan (N 26° 13´) is highly susceptible to sudden flushing during winter. The results suggested that urgent measures should be taken to alleviate low tea yields in the first crop in southern Japan.

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The objectives of this study were to determine the profiles of plasma estrogen concentrations during the first trimester of gestation and to correlate them with the origin of the embryos and fetal number. Pregnancies were induced either by artificial insemination (AI) on the day of estrus (day 0) or by transfer of 1 or 2 blastocysts produced in vitro (IVF-ET) on day 7. Five singleton-bearing cows impregnated by AI, and 6 singleton and 6 twin pregnancies induced by IVF-ET were used in the experiment. Blood was collected by jugular venipuncture at 2 to 5-day intervals until day 100. The concentrations of plasma estrone, estradiol-17β and estrone sulfate were measured by using a radioimmunoassay. Concentrations of all the estrogens fluctuated at low levels until day 50 in all the groups. Thereafter, the concentration of estrone sulfate gradually increased, whereas those of estrone and estradiol-17β remained at basal levels until day 80. The concentration of estrone sulfate after day 50 was affected by the day of gestation and the number of fetuses. After day 80, the concentration of estrone sulfate increased drastically, coinciding with the increases in the estrone and estradiol-17β concentrations. The rate of increase in the concentration of estrone sulfate during days 80 to 100 was the highest among all the estrogens. In the singleton pregnancies, the concentrations of estrone and estrone sulfate between days 80 and 100 were higher in the artificially inseminated cows than in the IVF-ET cows. In the pregnancies induced by IVF-ET, estrone sulfate levels were higher in the twin-bearing cows than in the singleton-bearing cows during days 50 to 80 and 80 to 100. These results suggest that the concentrations of estrogens in bovine peripheral blood plasma could be applied for monitoring fetoplacental development in the first trimester of gestation.

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The agar gel diffusion test (AGDT) was applied to detect Fasciola infection in several regions of Vietnam where equipment for fecal examination such as a microscope is not readily available. A 1% solution of agar dissolved in 10% saline, and the antigen prepared from adult individuals of Fasciola sp. were used for the test. The test was specific for Fasciola infection, which was detected in the sera from about 50% of the cattle and water buffaloes examined. The gel and antigen can be stored in a refrigerator for more than 3 months and used for the test. The results of this study revealed that the agar gel diffusion test could become a useful tool to diagnose fasciolosis in cattle and buffaloes at the Regional Animal Health Centers in Vietnam.

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Distribution of the moisture content across stem wood at breast height in Acacia mangium, A. auriculiformis, and hybrid Acacia trees grown in 3 Asian countries was evaluated. Moisture contents of the stems of A. mangium and hybrid Acacia were extremely high not only in sapwood but also in heartwood in most cases. Highest moisture content found in the inner heartwood was 253% for both A. mangium and hybrid Acacia. In sapwood, the moisture contents were 149% and 154%, respectively. Most trees of these 2 species had “wet-heartwood” which refers to the higher moisture content of heartwood compared to the surrounding sapwood. Stem wood of A. auriculiformis generally showed a slightly lower moisture content than that of A. mangium and hybrid Acacia. However, the highest moisture content found in the inner heartwood was 146% in A. auriculiformis. The large amount of water in stem wood, especially in the heartwood of these Acacia species hampers drying which is necessary for the production of sawn timber and processing to panel products. Several factors such as characteristics of clones or provenance of seeds, and amount of precipitation at plantation sites could be involved in the large fluctuations in the moisture contents of the stems of these Acacia trees. Further studies should be carried out to determine the conditions necessary for lowering the moisture content of stem wood in order to optimize the utilization of these plantation species.

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