Development of beta ray scanner for imaging foliar uptake of radiocesium

Large quantities of radionuclides were released from the Fukushima Daiichi Nuclear Power Plant(FDNPP)into the atmosphere,which then contaminated the soil and vegetation surrounding the FDNPP.The research on radiocesium contamination of agricultural products and wild plants is important.Therefore,we developed a simple beta ray scanner to obtain radiographs of the transport and foliar uptake of radiocesium.This simple beta ray scanner comprised a beta ray detector,a motorized sample stage,a shielding box,and a personal computer.Beta rays released from radiocesium were detected effectively using a plastic scintillator plate coupled to multipixel photon counter devices.The spatial resolving power was approximately 6 mm×4 mm(FWHM).In a preliminary experiment,a drop of radiocesium solution was placed on the upper surface of a radish leaf.Time-lapse images of radiocesium in the leaf were obtained by the beta ray scanner.Images of isotope transport in the leaf were successfully obtained with the beta ray scanner.The beta ray scanner will be used in our future research on the mechanism of the foliar uptake of radiocesium.

Kinetic study of phytotoxicity induced by foliar lead uptake for vegetables exposed to fine particles and implications for sustainable urban agriculture

At the global scale, foliar metal transfer occurs for consumed vegetables cultivated in numerous urban or industrial areas with a polluted atmosphere. However, the kinetics of metal uptake, translocation and involved phytotoxicity was never jointly studied with vegetables exposed to micronic and sub-micronic particles（PM）. Different leafy vegetables（lettuces and cabbages） cultivated in RHIZOtest？ devices were, therefore, exposed in a greenhouse for 5, 10 and 15 days to various Pb O PM doses. The kinetics of transfer and phytotoxicity was assessed in relation to lead concentration and exposure duration. A significant Pb accumulation in leaves（up to 7392 mg/kg dry weight（DW） in lettuce） with translocation to roots was observed. Lead foliar exposure resulted in significant phytotoxicity, lipid composition change, a decrease of plant shoot growth（up to 68.2% in lettuce） and net photosynthesis（up to 58% in lettuce）. The phytotoxicity results indicated plant adaptation to Pb and a higher sensitivity of lettuce in comparison with cabbage. Air quality needs, therefore, to be considered for the health and quality of vegetables grown in polluted areas, such as certain megacities（in China, Pakistan, Europe, etc.） and furthermore, to assess the health risks associated with their consumption.