Cytokinins found in cereal and legume seeds play important roles in seed development. While most cytokinins are produced within the seed itself, some are also transported from the parent plant. Trans-zeatin is a key cytokinin involved in seed growth and strength. Other forms of cytokinin in seeds have yet to be fully understood. Recent discoveries of genes responsible for trans-zeatin biosynthesis in rice highlight the significance of this cytokinin in plants.