Tomato (Lycopersicon esculentum) plants were grown in hydroponics. At the fruiting stage, N was withdrawn from the growing medium for a period of 19 days and its effects were studied on plant biomass production, photosynthesis, partitioning of 13 C and 15 N, and changes in the stem and fruit diameters etc, in order to monitor the mechanism of resource management on the plant parts at low N and prevent excess use of the fertilizer. N-deficiency treatment decreased leaf photosynthesis immediately and affected biomass accumulation of tomato. Conversely, N-deficiency increased stem diameter for a period of two weeks before reducing it below the control. During this period, these results suggest that N deficiency more suppress source activity than sink activity. N-deficiency reduced the amplitude of the circadian pattern of daytime shrinkage and nocturnal expansion of the stem diameter by decreasing the magnitude of the former. Circadian pattern of contraction and expansion of diameter was less evident in the fruit. Under N-deficiency, distribution of 13 C and 15 N decreased and increased to fruits respectively. Restricted partitioning of carbon to fruits could be responsible for accumulation of unused assimilates and consequential osmotic adjustment for maintenance of stem water potential. This effect might have precluded contraction of stem diameter of N-deficient plants until the production of assimilates became limiting on account of depression of leaf photosynthesis.

This paper presents a robot developed for reconnaissance at a nuclear power plant that had an accident. When an accident occurs, such as the Fukushima Daiichi Nuclear Power Plant disaster, rubble is scattered on the premises, increasing the radiation dose. Consequently, it is nearly impossible for humans to enter the plant and assess the situation. Therefore, a robot that performs reconnaissance is required. In this study, we designed and fabricated a reconnaissance robot to be used in a nuclear power plant that has undergone an accident. The inaccessibility of the scattered on-site rubble and high radiation dose can be addressed by employing an airship-type design that does not use electronic devices.

No abstract

No abstract

No abstract