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Quantitative imaging of 33P in plant materials using 14C polymer references

Koch, Maximilian, Schiedung, Henning, Siebers, Nina, McGovern, Sean, Hofmann, Diana, Vereecken, Harry, Amelung, Wulf
Analytical and bioanalytical chemistry 2019 v.411 no.6 pp. 1253-1260
autoradiography, carbon, corn, cost effectiveness, image analysis, leaves, luminescence, phosphorus, plant tissues, polymers, radionuclides, sediments, soil, wheat
Phosphorus (P) research still lacks techniques for rapid imaging of P use and allocation in different soil, sediment, and biological systems in a quantitative manner. In this study, we describe a time-saving and cost-efficient digital autoradiographic method for in situ quantitative imaging of ³³P radioisotopes in plant materials. Our method combines autoradiography of the radiotracer applications with additions of commercially available ¹⁴C polymer references to obtain ³³P activities in a quantitative manner up to 2000 Bq cm⁻². Our data show that linear standard regressions for both radioisotopes are obtained, allowing the establishment of photostimulated luminescence equivalence between both radioisotopes with a factor of 9.73. Validating experiments revealed a good agreement between the calculated and applied ³³P activity (R² = 0.96). This finding was also valid for the co-exposure of ¹⁴C polymer references and ³³P radioisotope specific activities in excised plant leaves for both maize (R² = 0.99) and wheat (R² = 0.99). The outlined autoradiographic quantification procedure retrieved 100% ± 12% of the ³³P activity in the plant leaves, irrespective of plant tissue density. The simplicity of this methodology opens up new perspectives for fast quantitative imaging of ³³P in biological systems and likely, thus, also for other environmental compartments.