Definition: Diffusion (lat diffundere = spreading) is a passive process that describes the tendency of particles to spread evenly throughout a space. In this way, after a certain time, there is always complete mixing of two different substances (concentration equalization).
Progress is being made on several fronts to introduce new traits into plants using recombinant DNA technology. The genetic manipulation of plants has been going on since the dawn of agriculture, but until recently this has required the slow and tedious process of cross-breeding varieties. Genetic engineering promises to speed the process and broaden the scope of what can be done.