“Live-autoradiography” technique reveals genetic variation of the rate of Fe uptake

Iron (Fe) is an essential trace element in plants; however, the available Fe in soil solution do not always satisfy the demand of plants. Genetic diversity in the rate of Fe uptake by plants has not been broadly surveyed among plant species or genotypes, although plants have developed various Fe acquisition mechanisms. The “Live-autoradiography” technique with radioactive 59Fe was adopted to directly evaluate the uptake rate of Fe by barley cultivars from a nutrient solution containing a very low concentration of Fe. The uptake rate of Fe measured by live-autoradiography was consistent with the amount of accumulation of Fe-containing proteins on the thylakoid membrane. These data revealed that the ability to acquire Fe from the low Fe so-lution was not always the sole determinant of tolerance to Fe deficiency among the barley geno-types. The live-autoradiography system visualizes the distribution of β-ray emitting nuclides and has flexibility in the shape of the field of view. Such a technique will strongly support phenotyping with regard to the long-distance transport of nutrient elements in the plant body