We all use cytokinins in different ratios to obtain callusing and differentiation of plant tissues but the mechanisms how this group of phytohormones work were enigmatic until recently. Although the full story has yet to come, the unravelling of Arabidopsis DNA base sequence published a couple of years back has made it possible to gain insights about the cytokinin receptor and many other missing links to show how cytokinins work. Please read the full story by clicking here. The story is based on an article published in the February issue of Plant Physiology
Explanation to the figure: A transgenic tobacco plant (right) with a high content of cytokinin shows fewer signs of senescence compared to a wild type plant (left) in which all the lower leaves are dead. The superimposed chemical structure is that of trans-zeatin, the principal cytokinin in higher plants.