Abstract: ABA localization in roots of Vicia faba L. was studied using immunogold microscopy. In cells of promeristem gold particles were mainly localized in the nuclei. In cells of ground meristem and cortex of the front part of elongation zone, some gold particles were found in cytoplasm near. the plasmalemma. Substantial amounts of gold particles were observed in cells of vascular cylinder especially in apoplast of vascular tissue. Cells of middle elongation zone and root hair zone were also labelled by many gold particles. In cells of the primary meristem and the front part of elongation zone, water stress could lead to acute increase of the gold particle density, and also in the cells of the elongation and root hair zone. The distribution of ABA in subcellular level and its relationship with transportation were discussed in the text. and the results provided evidence for ABA as a root-to-shoot transporting stress signal.

Key words: ABA, Immunogold microscopy: Water stress