VISUALIZING THE DISTRIBUTION OF ELEMENTS WITHIN BARLEY LEAVES BY ENERGY-DISPERSIVE X-RAY IMAGE MAPS (EDX MAPS)

X-ray image maps of transverse sections of barley leaf blades were com pared with individual X-ray emission spectra from vacuoles of barley l eaf mesophyll, epidermis and parenchymatous bundle sheath cells. Both forms of X-ray analysis revealed distinct patterns in element distribu tion within the leaf blade. Calcium and Cl predominated within the epi dermal cell vacuoles whilst P appeared mainly in the mesophyll cell la yer. Apparent accumulation of S and Mg within the bundle sheath cell v acuoles is discussed in relation to xylem unloading and sulphur assimi lation.