Utsunomiya University

About: Utsunomiya University is a education organization based out in Utsunomiya, Japan. It is known for research contribution in the topics: Laser & Holography. The organization has 4139 authors who have published 6812 publications receiving 91975 citations. The organization is also known as: Utsunomiya daigaku.

Effect of salinity on physiological characteristics, yield and quality of microtubers in vitro in potato

Abstract: In vitro microtuberization provides an adequate experimental model for the physiological and metabolic studies of tuberization and the preliminary screenings of potential potato genotypes. The effects of saline stress at 0–80 mmol concentration on in vitro tuberization of two potato cultivars were investigated in this study. With an increase in the salt concentration, the microtuberization of potato was either delayed by 5–10 days (20 and 40 mmol NaCl) or inhibited completely (80 mmol NaCl) in addition to the reduction in microtuber yields. The two potato genotypes studied showed different trends in total soluble sugars, sucrose and starch contents of microtubers under NaCl stress, while glucose and fructose levels remained unchanged. The vitamin C content in microtubers of two potato genotypes was reduced by salt stress. Salinity applied from 20 to 60 mmol progressively increased proline and malondialdehyde (MDA) levels in microtubers of both the potato cultivars. In genotype Zihuabai, NaCl at a low concentration (20 mmol) led to a significant increase in peroxidase (POD) and polyphenoloxiadase (PPO) activities, while in Jingshi-2, the PPO activity decreased progressively with an increase in NaCl concentrations. Genotype Zihuabai exhibited higher tolerance to salt stress than Jingshi-2 under in vitro conditions. These results could be used for preliminary selections of salt tolerance in potato breeding programmes.

Effect of the averaging volume and algorithm on the in situ electric field for uniform electric- and magnetic-field exposures.

Abstract: The present study quantified the volume-averaged in situ electric field in nerve tissues of anatomically based numeric Japanese male and female models for exposure to extremely low-frequency electric and magnetic fields. A quasi-static finite-difference time-domain method was applied to analyze this problem. The motivation of our investigation is that the dependence of the electric field induced in nerve tissue on the averaging volume/distance is not clear, while a cubical volume of 5 x 5 x 5 mm(3) or a straight-line segment of 5 mm is suggested in some documents. The influence of non-nerve tissue surrounding nerve tissue is also discussed by considering three algorithms for calculating the averaged in situ electric field in nerve tissue. The computational results obtained herein reveal that the volume-averaged electric field in the nerve tissue decreases with the averaging volume. In addition, the 99th percentile value of the volume-averaged in situ electric field in nerve tissue is more stable than that of the maximal value for different averaging volume. When including non-nerve tissue surrounding nerve tissue in the averaging volume, the resultant in situ electric fields were not so dependent on the averaging volume as compared to the case excluding non-nerve tissue. In situ electric fields averaged over a distance of 5 mm were comparable or larger than that for a 5 x 5 x 5 mm(3) cube depending on the algorithm, nerve tissue considered and exposure scenarios.

Influences of nitrogen load on the growth and photosynthetic responses of Quercus serrata seedlings to O3

Abstract: The objectives of this study were to clarify the influences of nitrogen (N) load on the growth and photosynthetic responses of Quercus serrata seedlings to O3 and to obtain basic data for evaluating the critical levels of O3 for protecting Q. serrata forests in Japan. The effects of O3 and/or N load on growth and photosynthetic activity of Q. serrata seedlings were investigated during the two growing seasons. Two-year-old seedlings were assigned to 12 experimental treatments, which were comprised of the combination of four gas treatments (charcoal-filtered air and three levels of O3 at 1.0, 1.5 and 2.0 times ambient concentration) and three N treatments (0, 20 and 50 kg ha−1 year−1). During the second growing season, no significant interactive effects of O3 and N load on the growth and net photosynthetic rate of the seedlings were detected. Threrfore, we concluded that N supply to the soil at ≤50 kg ha−1 year−1 does not significantly influence the growth and photosynthetic responses of Q. serrata seedlings to O3. Based on the O3 exposure-response relationships for the whole-plant growth of the seedlings, the critical level of O3 for Q. serrata was estimated to be approximately 36 nmol mol−1 as the average 15-h O3 concentration during the one growing season.