Calcium Localization within Live Oat Leaves Using a Semiconductor Detector Assembly

Pathways of movement of foliar-applied 45Ca in young oat leaves are localized by means of in-vivo β spectrometry with a semiconductor detector assembly. The shift of the maximum energy of the observed spectra to the lower-energy region, which is a function of the thickness of the tissue layer between an internal 45Ca source and the detector, is the most reliable and easily interpretable parameter for 45Ca localization. Transport of foliar-applied Ca occurs in the vascular bundles. The major part of the transported Ca moves out of the conducting tissue and accumulates in the mesophyll and epidermis cells. The passage from the transport to the accumulation phase is a rapid process. These results are compared with those obtained by histoautoradiography.