Changes in the pattern of phospholipid synthesis during the induction by cytokinin of cell division in soybean suspension cultures.

A method is described for preparing fully viable, cytokinin-starved soybean (Glycine max (L.) Merr. cv. Acme) cells from a suspension-culture of callus tissue. The cells respond to kinetin treatment by re-initiating cell division. We present evidence, from the pattern of incorporation of (32)P-labelled inorganic phosphate into individual phospholipids during the first hour of this response, that the synthesis of phosphatidylinositol (PI) and of phosphatidic-acid head-groups is affected within 15 min. The polyphosphoinositide phosphatidylinositol 4-phosphate, but not phosphatidylinositol 4,5-bisphosphate, was detected in the tissue. The characteristics of cytokinin-induced PI synthesis in cytokinin-starved soybean cells appear to resemble the 'PI response' of animal cells.