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CYT KININS by Philip McIntosh
Cytokinins are often used by farmers to promote plant growth , and are known to play a role in plant pathogenesis . Philip McIntosh provides a closer look at the role these important molecules play .
THE CYTOKININS ARE a class of organic molecules that regulate growth and development through cell division in plants .
THE NAME “ CYTOKININ ” is indicative of its action . Cytokinins promote “ cytokinesis ,” more commonly known as cell division .
IN THE EARLY 1900s , researchers noticed that some plant extracts , especially coconut milk , had the ability to stimulate cell division , but the identity of the active agent was unknown .
OF THE MORE than 200 known cytokinins ( both natural and synthetic ), most are structurally derived from adenine , which also provides the ‘ A ’ in the ATCG sequences of DNA .
ENTER FOLKE SKOOG ( of Murishage and Skoog medium fame ) who , working in the 40s and 50s , identified the first cytokinin , kinetin .
KINETIN DOES NOT occur in plants but was discovered after trying many substances in an effort to produce the same effect as coconut milk .
A WELL-KNOWN plant-produced cytokinin is zeatin , found in coconut milk , but first isolated from corn kernels ( hence the name , since corn is Zea mays ).
THE EFFECTS OF cytokinins are diverse and include activity with respect to bud and leaf initiation and expansion , apical dominance , chlorophyll biosynthesis , and many others .
ALTHOUGH , DEPENDING on the stage of growth and development , cytokinins can be found in abundance in just about any plant tissue , the highest concentrations are found in root tips , embryos , and apical buds .
CYTOKININS ARE important in plant tissue culture and are available commercially in purified form from many suppliers .
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