Efficient plant regeneration from multiple shoots formed in the leaf-derived callus of Lavandula vera, using the "open culture system".
Abstract To develop an efficient procedure for plant regeneration from leaf-derived callus of Lavandula vera DC, the production of multiple shoots and the formation of roots from these shoots were studied. When calli were cultured in a medium with 4.0×10−7 M N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU), urea-type cytokinin, multiple shoots were obtained from the greenish surface of the callus efficiently at a rate of 52.2%. For multiple shoot development, the shoots were divided into 7–20 shoot clusters with 2–3 shoots and subcultured every 2 weeks. Two modified culture-systems were employed for subculture; a “closed culture system” and an “open culture system”. In the open-system, shoot clusters grew and elongated vigorously. In the closed-system, most of the clusters showed vitrification and did not elongate. In root induction culture, shoot clusters in the open-system were well rooted and grew vigorously, the highest rate of root formation being 74.0%, in the 1 2 MS medium supplemented with 1.0×10−6 M indoleacetic acid (IAA). On the other hand, shoot clusters in the closed-system showed vitrification and did not root well. About seven times more regenerants were obtained from the multiple shoots than from normal shoots treated with 4.4×10−6 M 6-benzylamino purine (BA), a purine-type cytokinin. These results indicate that efficient plant regeneration in L. vera from callus using multiple shoots is possible by means of an open-system.
Carbon dioxide and ethylene evolution in the culture atmosphere of Magnolia cultured in vitro
Subcultured explants of Magnolia soulangeana Soul, were incubated in tissue culture containers fitted with different types of closures. Type of closure affected the CO2 concentration, with levels as high as 14% CO2 being detected. The ethylene concentration increased gradually with time, to as much as 2–3 ppm after 9 weeks. There was a large variation in the composition of the atmosphere within the containers of any one type. The way by which a container was closed influenced exchange of the inner gas phase with the surrounding atmosphere and was important in determining the development of the cultured tissues.
Prediction of a representative point for rail temperature measurement by considering longitudinal deformation
Monitoring rail temperature is very important for determining the safe running speed of trains and to prevent buckling. In general, the maximum variation of the internal rail temperature can be >7 ℃ depending on the point of measurement. However, there is as yet no sufficient information about how to predict the measurement point to represent the thermal deformation due to temperature distribution. In this study, the authors report a new point, called the representative measurement point, at which the rail temperature can be measured. This point considers the average deformation of the rail through structural analysis by adopting experimental and actual rail temperature data. The authors designed and installed a measurement system similar to an actual rail environment. Using the system, various data were acquired (internal/surface rail temperature and weather data) for 10 months. On the basis of these data, an analysis was done to calculate the average deformation point through thermal analysis. Finally, the representative measurement point was proposed as the position at which the average deformation point converges regardless of weather or seasons. The authors believe that the method described herein is advantageous in that it could be used in a high-accuracy temperature-monitoring system and for predicting thermal deformation and buckling.