To investigate effects of CO₂ concentration, light intensity, and nutrient solution strength on the growth of wasabi (Eutrema japonicum (Miq.) Koidz.) seedlings, they were grown in environmentally controlled chambers. In the first experiment, single effect of CO₂ concentration on growth of wasabi cultivar ʻIzumaʼ was investigated. The dry weight of the whole seedling was increased more under enriched CO₂ concentrations (1000 and 2000 ppm (v/v)) than under ambient CO₂ concentration (400 ppm). However, the CO₂ effect to raise photosynthesis was weakened in the latter half of the experiment. To sustain the effect of the enriched CO₂ throughout the whole seedling cultivation period and maximize the wasabi seedling growth, the wasabi seedlings were grown under different light intensities and different nutrient solution strengths in the second experiment. Two wasabi cultivars ʻIzumaʼ and ʻFujimidoriʼ were used. ʻFujimidoriʼ is a newly developed cultivar that is more tolerant to high temperatures. The results revealed that ʻFujimidoriʼ had the highest whole dry weight under enriched CO₂ concentration (1000 ppm), higher light intensity (200 µmol m^-2 s^-1), and higher concentration of the nutrient solution. Contrary, the whole dry weight of ʻIzumaʼ under such environmental conditions was almost the same as that of ʻIzumaʼ grown under a lower concentration of nutrient solution but enriched CO₂ concentration and higher light intensity, and under lower light intensity but enriched CO₂ concentration and higher concentration of nutrient solution. This suggests that a combination of a higher concentration of the nutrient solution and higher light intensity cannot amplify the CO₂ effect on ʻIzumaʼ growth. The difference in the environmental response between the two cultivars seemed to be partially caused by the different temperature tolerances.

In recent years, space agencies including NASA, academia, non-profit organizations, and private companies have been considering potential human settlement sites on Mars. The First Landing Site/Exploration Zone Workshop for Human Missions to the Surface of Mars was conducted in the United States in 2015. At the workshop, 47 teams analyzed separate exploration zones under the same rubric and criteria to identify potential landing sites, areas of scientific interest, and areas of resource interest. Most of the studies focused primarily on scientific exploration, and did not analyze from a perspective of settlement. In this paper, Mars Society Japan compared the same 47 exploration sites from four main perspectives: "local water resource usage," "atmospheric thickness corresponding to altitude," and "latitudes with sufficient sunlight for agriculture," to determine settlements capable of accommodating up to 10,000 people. In total, four locations were selected as candidates. Two of the locations coincided with potential settlement sites selected by SpaceX for city construction.

Green onions (Allium fistulosum L.) are an essential flavoring vegetable in Asian cuisine with high nutritional value. To ensure their stable future production, efficiently cultivating them in plant factories is necessary. In this study, we investigated the effects of spectral photon flux density and lighting position and direction for green onion production using two cultivars (ʻWhite Starʼ and ʻFukuichi-Negiʼ). First, we investigated the effects of four types of light-emitting diode (LED) lamps with or without far-red light and different red/blue (R/B) ratios on the growth of the green onion cultivars. ʻWhite Starʼ had the highest shoot fresh weight when grown under low blue-light ratio LED lamps with far-red light, while ʻFukuichi-Negiʼ had the highest shoot fresh weight under medium blue-light ratio LED lamps. The R/B ratio and far-red light affected green onion growth, with the effect varying among the varieties. Furthermore, we investigated a light irradiation method to increase the production efficiency of green onions. We compared the growth of the two green onion varieties by irradiating the top of the plants (conventional method) or their sheath base from the lateral direction (sideward irradiation). The results showed that the shoot fresh weight of ʻWhite Starʼ and ʻFukuichi-Negiʼ grown under sideward irradiation were 1.5- and 1.3-fold higher than those under the conventional method, respectively.

This study provides important knowledge for improving the efficiency of green onion production in plant factories using LEDs.

Recovery of plant nutrients from food residue is one of the most effective methods for resource recycling. To use food residue for hydroponics, the organic matters have to be mineralized and the nutrients have to be dissolved. Anaerobic digestion, biological oxidation, anaerobic digestion followed by biological oxidation, and wet oxidation are treatments to break down organic matter. The decomposition products of these processes are in liquid form and would be used as liquid fertilizer. The authors investigated the difference in the behaviour of nitrogen, potassium, and phosphorus in each treatment. Nitrogen was converted to ammonium by anaerobic digestion and wet oxidation, and to nitrate by biological oxidation. Potassium did not change significantly with treatment. The percentage of dissolved phosphorus in all treatments, especially in the microbial treatment, was smaller than in food residue. This is probably due to phosphorus binding to other ions and uptake by microorganisms during the treatment process.

The influences of quercetin on the productions of lipid peroxides, anisidine-reactive compounds and ozone in autoxidation of α-linolenic acid were investigated. Lipid peroxide concentration, anisidine value and ozone concentration significantly increased in the autoxidation of α-linolenic acid for 5 days. On the other hand, the addition of quercetin as a natural antioxidant agent efficiently suppressed the increases in the generations of these peroxidation products. The increase in ozone concentration was correlated with the increase in anisidine value, but not the lipid peroxide concentration. The oxidative cleavage of double bonds in α-linolenic acid and lipid peroxides by ozone generated in the autoxidation seems to be involved in the productions of anisidine-reactive compounds. Quercetin inhibited the process of productions of anisidine-reactive compounds by inhibiting the generation of ozone from lipid peroxides. Next, the direct effect of autoxidized α-linolenic acid on λDNA was evaluated. The autoxidized α-Linolenic acid degraded λDNA dependently upon the increase in anisidine-reactive compounds. On the other hand, the addition of quercetin during the autoxidation of α-linolenic acid significantly inhibited the degradation of λDNA. 2,4-Heptadienal and trans-2-pentenal efficiently degraded λDNA, suggesting that the DNA-degrading compounds in autoxidized α-linolenic acid might be these aldehydes.