Numerous studies on the reclamation of saline land have been conducted in northeastern Thailand. Despite the importance of long-term evaluations of this phenomenon, relatively few studies on this have been reported in the scientific literature. Consequently, we propose a new method for understanding the 3D salt distribution in soil. The general technique employed for evaluating salt accumulation in soil is to measure the electrical conductivity of soil samples in the laboratory. However, the collection of soil samples can be difficult when groundwater levels increase such as they do during the rainy season in northeastern Thailand. We therefore developed an instrument capable of measuring electrical conductivity in saturated soils below groundwater level. The method for determining the 3D salt distribution in soil employs an electrical conductivity probe and measurement of the geographical location of the sample site by GPS. The probe is used to measure electrical conductivity at a point perpendicular to the ground surface, and these values are then combined with the horizontal 2D coordinates for the sample site. The combination of these data can be used to determine the 3D salt distribution in soil. A field experiment was conducted in northeastern Thailand during the rainy season. By measuring the electrical conductivity at specified depths and recording the corresponding 2D location data, we were able to determine of the 3D salt distribution in soil. In addition, the outputs obtained using the electrical conductivity probe were almost equivalent to electrical conductivity measurements obtained from soil solutions (EC_e) in the laboratory. We also demonstrated that it was possible to assess the 3D distribution of soil salts in a region in a day. The application of the proposed method thus makes it possible to continuously investigate the salt distribution at numerous sample sites spread across a region.

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In previous studies, the optimum farming condition for mushrooms has been investigated using the bio-electric potential of mushrooms as an index. In this study, the electric potential resulting from external stimulation has been examined at the cellular level using optical measurement method, employing the voltage-sensitive dyes in order to investigate the micro dynamics of the generation and spread of the bio-electric potential. The results indicated that the absorbance of the dye was seen to temporarily increase with pulse-current stimulation at a wavelength of 540 nm, whilst it decreased at a wavelength of 700 nm. The absorbance reaction, or 'the reverse wavelength', caused by absorbency characteristics of the dye proved that the measured changes reflected a potential change in the spawn cells. In addition, a spread of the potential reaction over the spawn cells was observed.

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"Integrated IonAdjuster System" (IIA System) integrated an ion concentration control method with an EC control method for controlling nutrient solution in hydroponics was developed. The IIA System adopted the EC control method for real-time control of total ion concentrations, and adopted the ion concentration control system for preparation of the stock solutions which could adjust ion composition of nutrient solutions. Cultivation of cucumber using the IIA System led to laborsavings, sustained good condition of rhizosphere, and increased yields. Moreover saving initial and running cost should be possible in the IIA System, and consequently the IIA System may contribute to promotion of closed hydroponic system.

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Gibberellin (GA) are plant hormones play important roles in plant development. GA biosynthetic pathway and the genes encoding most of the GA biosynthetic enzymes have been characterized. GA 3β-hydroxylase (Ls3h1) is an enzyme that catalyzes the late steps in the formation of active GAs, and is a potential control point in the regulation of GA biosynthesis by light. Red light promotes GA₁ synthesis in lettuce seeds by inducing Ls3h1 gene expression via phytochrome action. Endogenous GA₁ content, the main bioactive GA in lettuce, increases after red-light treatment.
The final goal of this research is to develop a new strategy for environmental control of green houses in lettuce production.
We investigated the influence of light irradiation on Ls3h1 gene expression and leaf elongation in leaf lettuce (Lactuca sativa L. cv. "Green wave"). Ls3h1 gene expression was analyzed by real time RT-PCR. Leaf elongation was measured using an image analysis system that consisted of an infrared camera and an infrared lamp to capture plant images every 10 minutes for 2 days.
Image analysis indicated that rate of leaf elongation was increased at 30minutes after starting the light period, and uniconazol inhibited this elongation. Real time RT-PCR analysis showed that Ls3h1 gene expression was increased at 5 minutes after starting light period, and that this gene expression was maintained.

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In our previous study, it has been proved that photosynthetic abilities in leaves, e.g. maximum net photosynthetic rate, decreases with depth from the top of the year-round cultured tomato plant canopy in a large-scale greenhouse. In this study, we assessed the distribution of photosynthetic abilities within tomato plant canopy by measuring chlorophyll fluorescence parameter (F_v/F_m), SPAD value and chlorophyll concentrations and then investigated the relationships among these parameters. Maximum net photosynthetic rates in leaves within middle and lower layers decreased to half and seventh parts of that within upper layer, respectively. F_v/F_m significantly increased with depth in the canopy, however, SPAD value and chlorophyll a/b ratio significantly decreased with depth in the canopy. Low chlorophyll a/b ratio and high F_v/F_m in leaves within the lower layer suggested that these leaves acclimated to the low light condition and had high light-utilization efficiency for photosynthesis. These results indicated that the decreases in the photosynthetic abilities in leaves with depth in the tomato plant canopy are caused by the low-light acclimation. Furthermore, the correlations between chlorophyll a/b ratio and F_v/F_m, and SPAD value were observed. This result suggested that the measurements of F_v/F_m and SPAD value can be used as a rapid and concise tool to assess the photosynthetic abilities in leaves within tomato plant canopies.

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The objective of this experiment was to elucidate the effects of a daily 6h-dark interval in continuous fluorescent illumination with temperature alteration to decrease the pungency level in sweet pepper 'Shishito' production. Plants were grown in a closed environment in half-strength "Otsuka-A" nutrient solution (EC 1.4 dS m^-1), whose pH was adjusted to 5.6, with a range of light intensity between 150 and 350 μmolm^-2s^-1, 800 ppm CO₂ enrichment and ambient humidity.
In experiment 1, seedlings were grown under a 18/6 hr (light/dark) cycle with corresponding temperatures of 28/20°C for 80 days (1-I period), 28/16°C for 60 days (1-II period) and 28/28°C (1-III period). In experiment 2, seedlings were grown either under continuous fluorescent illumination and a constant temperature of 28°C for 80 days (2-I period) or a 18/6 hr (light/dark) cycle with corresponding temperatures of 28/16°C (2-II period).
Green peppers were harvested at marketable size. Capsaicin was extracted from the fruit placenta with methanol and its concentration was determined with HPLC. Fruits under continuous fluorescent illumination and constant 28°C (2-I period) had fewer seeds and a higher concentration of capsaicin than greenhouse fruits harvested in summer. Capsaicin concentration decreased and the number of seeds increased with a daily 6h-dark interval in continuous fluorescent illumination with temperature alteration. These results suggest that there is a negative correlation between seed formation and capsaicin biosynthesis.

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The biodegradation and composting of wood meal waste after sawdust-based cultivation of nameko (Pholiota nameko (T. Ito) S. Ito) were investigated using commercial microorganism-degrading agents, and the availability of the products as fertilizer was evaluated. After 15 days of culture, the cultured waste decreased its volume to about half, and the grain size decreased. The weight-loss percentage of the culture increased with the increase in the mixture ratio of the degradative promoters. The pH of the culture, which was originally 3.8, decreased to 5.3-6.0 (weak acidity) after biodegradation, and the CN ratio decreased. Cultivation tests of the biodegradated products as compost showed no inhibitory activities for the germination and growth of komatsuna (Brassica campestoris). The results obtained suggest that the products obtained from nameko-cultivation waste biodegraded with microorganisms can be used as compost.

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Various mineral elements were incorporated into lettuce grown in hydroponics to find suitable mineral elements for developing a marking system to certify the provenance of vegetables. Seven mineral elements (Ba, Sr, Mo, Co, Cu, Ni and V) were selected as candidate markers, since the natural abundance of these elements in lettuce were low and they seem to have comparatively low toxicity to human and vegetables. Two varieties of lettuce (Lactuca sativa L., cv: Red-fire and Rakuten) were cultivated in nutrient solution containing each of these elements at various concentrations. Lettuce grown under all treatments with Ba, Sr and Mo and under treatment with Cu at 0.25 and 0.50 mg l^-1 and with Ni at a concentration range of 0.05-0.50 mg l^-1 showed favorable growth similar to the control, whereas under treatment with Co, Cu and Ni at 5.00 mg l^-1 and with Cu at 10.00 mg l^-1 , plants showed unfavorable growth. Vanadium was hardly absorbed by lettuce. Concentrations of Ba, Sr, Co, Mo, Cu and Ni in tops of lettuce were increased in proportion to increase in the actual concentration of each element in nutrient solution.
In addition, amounts of elements contained in 470 g of treated lettuce (amount recommended by the Ministry of Health and Welfare of Japan for daily consumption by adult) in several treatments were lower than the Acceptable Daily Intake (ADI) or Tolerated Daily Intake (TDI) and were obviously higher than their natural abundances. These results suggest that Ba, Sr, Mo, Co, Cu, and Ni could be used as marker elements to certify the provenance of lettuce grown in hydroponics when lettuce is cultivated using a nutrient solution within a suitable concentration range.

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Three mineral elements, barium (Ba), strontium (Sr) and molybdenum (Mo), were simultaneously incorporated into lettuce (Lactuca sativa L.) grown in hydroponics as markers for certifying vegetable provenance. When lettuce was cultivated in nutrient solutions with combinations of the three elements at various concentrations, the concentrations of these elements in the top of lettuce were increased with increase in the concentration of each element in nutrient solutions without absorption interference of these elements with each other. These element concentrations in tops were statistically evaluated by canonical discriminant analysis, then eight treatments prepared using combinations of these elements at various concentrations in nutrient solutions were obviously distinguished from each other: i.e., the probability of miss judgment was zero and the rate of correctness of judgment was 100%. Therefore, eight different labels can be incorporated into lettuce using combinations of these elements. Amounts of the three elements contained in 470 g (the value to be consumed daily recommended by the Ministry of Health, Labor and Welfare of Japan) of fresh plants grown thus manner were lower than those of Acceptable Daily Intake or Tolerated Daily Intake for the respective elements. These findings suggest that a digital marking system by introducing mineral elements into lettuce grown in hydroponics can be of practical use for certifying its source.

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