Effects of Cytokinin and Several Inorganic Cations on the Polyamine Content of Lettuce Cotyledons

Kinetin (4.7 x 10^–5 M) and 6-benzyladenine (2.22 x 10^–5M) were found to increase ca. 2-fold the putrescine contentin cotyledons of lettuce (Lactuca sativa L.) seedlings grownfor 3 days under fluorescent light. On the other hand, severalinorganic ions (K⁺, Na⁺, Ga⁺⁺, Mg⁺⁺) at a concentration of 3x 10^–2 M reduced the putrescine content. The combinationof kinetin with one of several inorganic ions at the same levelmarkedly increased the spermine content, but the putrescinecontent decreased; calcium and magnesium ions were less effective.The physiological significance of these findings is discussed. (Received July 4, 1982; Accepted November 6, 1982)