Vacuolar Autophagy: Apparent Dilution and Elimination of Cytoplasmic Organelles in Acridine Orange-Treated Plant Cells

SUMMARY

Plant vacuoles which are structurally as well as functionally analogous to animal lysosomes; accumulated cytoplasmic masses when root tips were treated with aqueous solutions of acridine orange. The intravacuolar cytoplasmic masses were composed of recognizable cytoplasmic organelles viz. mitochondria, endoplasmic reticulum and ribosomes. These organelles were diluted by the hydrolytic enzymes present in the lysosomic vacuoles. If the root tips were treated for a longer time, vacuoles also accumulated the dye; which formed a complex with heavy metals used during processing of the tissue for electron microscopy. As a result of formation of this complex the peripheral membranes of autophagocytosed organelles appeared extraordinarily thick.