Introduction of DNA into plant cells without the involvement of a biological agent and leading to stable transformation is known as direct gene transfer. Certain chemicals, eg, PEG (Polyethylene Glycol), polyvinyl alcohol and calcium phosphate enhance the uptake of DNA by plant protoplast. PEG and calcium phosphate are thought to precipitate the DNA onto the outer surface of plasmalemma and the precipitate is taken up by the endocytosis.