Abstract: Plant peroxisomes play a key role in numerous physiological processes and are able to adapt to environmental changes by altering their content, morphology, and abundance. Peroxisomes can multiply through elongation, constriction, and fission; this process requires the action of conserved, as well as species-specific proteins. Genetic and morphological analyses have been used with the model plant Arabidopsis thaliana to determine at the mechanistic level how plant peroxisomes increase their abundance. The five-member PEX11 family promotes early steps of peroxisome multiplication with an unknown mechanism and some subfamily specificities. The dynamin-related protein (DRP)3 subfamily of dynaminrelated large guanosine triphosphatases mediates late steps of both peroxisomal and mitochondrial multiplication. New genetic and biochemical tools will be needed to identify additional, especially plant-specific, constituents of the peroxisome multiplication pathways.

Key words: Arabidopsis, dynamin-related proteins, peroxisome multiplication, PEX11.