The present invention provides a novel method for the transduction and/or transfection of plant cells. Cell-penetrating peptides (CPPs) have been successfully employed as nanocarriers to deliver proteins and oligonucleotides to single plant cell microspores as well as multi-cellular zygotic embryos. The efficiency of CPP internalization and further delivery of a macromolecular cargo comprising a protein and/or an oligonucleotide can be enhanced by permeabilization of the zygotic embryos.