Protoplasts

Plant cells that have been stripped of their cell walls

If plant cells are freed from their cell walls, they take on a spherical shape. Cells are suspended in solutions with carefully adjusted osmotic pressures to keep the cells from bursting.

Certain chemical or electrical stimuli can be used to induce protoplasts to fuse and thereby randomly exchange genetic information (protoplast fusion). Oftentimes, cells of different species can be fused, e.g. tomatoes and potatoes. However, it is rarely possible to regenerate entire plants from such hybrids.

Genetic engineering is different because it involves the transfer of individual, known genes.