Changes of Ca 2+ distribution in root apical meristematic cells of wheat under aluminum stress were observed with electron microscopic cytochemical method. When the roots grew in non aluminum environment, it was shown that the calcium antimonates distributed in cytoplasm, nucleus and intercellular spaces, especially in the vacuoles of cytoplasm. When the roots grew in aluminum stressed environment, the number of calcium antimonate in cytoplasm and nucleus decreased, and its distribution changed signi...