1. Auxins and cytokinins are growth promoting substances which stimulate cell division and cell enlargement.
2. A high cytokinin promotes shooting in plants.
3. A low ratio of cytokinin to auxin induces root development.
4. A high ratio of cytokinin to auxin induces growth of buds and shoot development.
5. Thus cytokinin and auxin ratio and their interactions control morphogenesis in plants.