The single truss tomato production system (STTPS) was used to grow tomato plants at a density of 14.3 plants·m−2 for increasing the tomato yield in Japan. We applied supplemental lighting within the canopy at different tomato development stages to identify the most sensitive stage at which supplemental lighting will most effectively increase yield and quality of tomato fruits. Fluorescent lamps were used to supply intra-canopy lighting to tomato plants (5:00–21:00) during the stages of anthesis (stage 1), rapid fruit development (stage 2), fruit ripening (stage 3), and from initial anthesis to red-ripe fruit (whole stage), respectively. Supplemental lighting applied to tomato plants during stage 2 and whole stage significantly increased the yield and sugar content of tomato fruits. Moreover, the contribution of supplemental lighting to the daily increase of tomato yield was highest at stage 2. The increase of fruit fresh weight and amount of supplemental lighting showed positive linear relationship. Supplemental lighting did not affect the ascorbic acid content of tomato fruits, fruit number per plant, and plant shoot weight among all the treatments. Thus, based on economic advantage, the use of supplemental lighting during the rapid fruit development stage of tomato plants under STTPS was most efficient.
This genus Asparagus (Asparagaceae) includes commercially important species of vegetable as well as some ornamentally or medicinally important species, and it needs molecular markers to conduct precious identification. Therefore, we compared results of phylogenetic analyses based on different molecular approaches for this genus. To reconstruct phylogenetic trees, we used three data sets, sequences of some chloroplast DNA (cpDNA) regions and the internal transcribed spacer (ITS) 1 region, and random amplified polymorphic DNA (RAPD) for seven samples selected from all subgenera in this genus. Both trees of the ITS region and the RAPD analysis have higher resolutions than those of cpDNA sequences. However, the tree of RAPD analysis has low a value of consistency index (CI) due to parallelism of many characters. The tree of ITS1 sequences provided appropriate resolution and a high CI value. Therefore, ITS sequencing is overall the most efficient approach for clarifying the phylogenetic relationship among the species of Asparagus.
Supplementary lighting with blue-violet light-emitting diodes (LEDs) was tested to reduce the onset of pathogenic disease in tomato plants grown in the greenhouse. Tomato plants (cvs. Reika and Momotaro) were cultivated on rockwool under drip irrigation without the application of any agricultural chemicals. Supplementary lighting systems consisting of LED units fitted with 12 LED lamps (peak wavelength 405 nm) were developed to irradiate the plants. Supplementary lighting was provided in the early morning (from before sunrise) and early evening (till after sunset) at a power consumption of 6–12 W per plant. The onset of pathogenic disease was visually inspected and compared with that of control plants cultivated without supplementary lighting. Supplementary lighting of 405 nm LED reduced the onset of black leaf mold (Pseudocercospora fuligena). As a result of analysis of the relationships between environmental factors and the suppressive effect of LED irradiation, it was observed that supplementary lighting with 405 nm LED was effective in disease suppression at high temperature. These findings indicate that 405 nm LED irradiation has the potential to provide tomato plants protection from disease, and this technique is therefore expected to contribute to a reduction in the use of agricultural chemicals in protected cultivation.
Leaf gas exchange, chlorophyll fluorescence, and ascorbic acid contents of rice grown at ambient and elevated CO2 concentrations (400 and 800 cm3 m−3, expressed as C400 and C800) were examined under three O3 concentrations (0, 0.1 and 0.3 cm3 m−3, expressed as O0, O0.1 and O0.3) to elucidate the effects of acute O3 exposure. The net photosynthetic rate, maximum and operating quantum efficiencies of photosystem II decreased immediately after O3 exposure, but these were ameliorated by C800. The acclimation of stomatal conductance to elevated CO2 occurred in rice leaves of C800 plants. Therefore, it was anticipated that O3-induced injury of photosynthesis in the C800+O0.3 plants was more suppressed than in C400→C800+O0.3 plants (grown at C400+O0 and received acute C800+O0.3 exposure). However, no significant difference was found between these plants. The contents of total ascorbic acid, reduced form of ascorbic acid (AA) and dehydroascorbic acid, and redox state of ascorbic acid were unaffected by C800 when they were expressed per leaf area. However, the total ascorbic acid and AA contents per fresh and dry mass bases were decreased by C800 because the specific leaf weight was increased significantly by C800. Therefore, long-term exposure of rice plants to elevated CO2 might have little effect on antioxidant systems.
A growth distribution map of grassland was created by measuring the grass top altitude using a three-dimensional (3D) laser scanner (LS). This grass top altitude was then subtracted from the ground terrain map to generate the grass height map. The ground terrain was measured using both a tractor-based surveying system (TBSS) and the LS. The root mean square (RMS) error of the measured height that was calculated using the LS was 7.4 cm when the ground altitude was measured by the TBSS, and 9.8 cm when the altitude was measured by the LS. Correlations were observed between the yields measured from a quadrate and the average height measured by the TBSS and LS and only by the LS. In this study, the potential of using the LS and TBSS for estimating grass height and yield mapping are discussed. For the experiment, the land of the site was smoothed and the grass height and yield were strongly related to the banking and cutting of soil. The findings show that creating a precise growth map is useful for farmers, agronomists, and soil scientists.
A new tomato growth model was developed based on an existing growth model to predict the growth and yield of tomato plants cultivated with a low node-order pinching system at high plant density, under annually variable environmental conditions in Japan. Over a 5-year period, we obtained the growth and yield data of 2 tomato Japanese cultivars in a large-scale commercial greenhouse, in correlation with environmental data (i.e., radiation, air temperature, humidity). We calculated the sink strength of each vegetative organ and fruit and determined cultivar specific constants, by modifying an existing process growth model developed for long-term cultivated tomatoes. The accuracy of the modified simulation, regarding the growth and yield of tomato plants, cultivated with a low node-order pinching system at high plant density, was improved by the modification of cultivar specific constants and calculation methods of fruit sink strength, with an overall error of just 16.5%.
In the present study, we investigated the effects of supplemental lighting (SL) with white, red, and blue light-emitting diodes (LEDs) on the yield and quality of tomato grown under the single-truss tomato production system (STTPS). SL was applied for 28 days during the rapid fruit development stage. Based on the same power consumption, the light treatments with the white and red LEDs increased the fresh yield of tomato by 12 and 14%, and the dry yield by 16 and 14%, compared with the control (without SL), respectively. Based on the unit photons emitted, the white LEDs showed high efficiency as the red LEDs in increasing tomato yield, followed by the blue ones. The results were probably due to the white LEDs that contained more than 50% of green light characterized by high penetration into the canopy. The sugar and ascorbic acid contents were not affected by SL from the LEDs. These results indicated that the white and red LEDs were effective in enhancing tomato yield and, in particular, the white LEDs with a combination of red, blue, and abundent green light would be more suitable to the use of STTPS at a high plant density.
Eggplant (Solanum melongena L.) fruit contains several anthocyanins, and their levels are well known to fluctuate depending on the light condition. In eggplant, although two major anthocyanins, nasunin and tulipanin, have been isolated from the fruit, the inheritance mode of their light-dependent formation is not clear. In this study, to clarify the genetic characteristics of anthocyanin production and photosensitivity in eggplant fruits, we investigated the segregation and photosensitivity of anthocyanin in the F1 and F2 hybrids of ‘Kumamoto-naga’ (Japanese eggplant containing nasunin) and ‘Black Beauty’ (American eggplant containing tulipanin) grown under normal or dark conditions. The major anthocyanin of the F1 fruit was nasunin. In the F2 fruit the anthocyanins were present in a ratio of 3:1 (nasunin: tulipanin). In addition, based on the results obtained under dark conditions, the genetic characteristic of photosensitivity in the major anthocyanins was segregated into the ratio of 9:3:3:1 (nasunin of the non-photosensitive type : nasunin of the photosensitive type: tulipanin of the non-photosensitive type: tulipanin of the photosensitive type). These results reveal that the inheritance of major anthocyanins (nasunin and tulipanin) and that of the photosensitivity (photosensitive type and non-photosensitive type) of anthocyanin production do not interact but are independent.
Oyster shell powder (an industrial waste) was reacted with diammonium phosphate with calcium to phosphate mole ratios of 5:5, 5:4, and 5:3 at both room (25–28°C) and high (100°C) temperatures to form apatite-like compounds. Oyster shell powder could react with the diammonium phosphate but crystallinity and the cadmium immobilizing effect were poor compared with commercially available hydroxyapatite. Calcium hydroxide was added to the oyster shell powder with an oyster shell to calcium hydroxide mole ratio of 6:4. When this mixture was reacted with 6 moles of diammonium phosphate under the same temperature conditions, a compound with crystallinity close to that of commercially available hydroxyapatite and a higher cadmium retention capacity could be synthesized. It was demonstrated that the cadmium immobilizing ability of this compound in soil is even larger than that of commercially available hydroxyapatite and also has an excellent soil neutralizing ability.