Effects of the growth regulator 4PU-30 on growth, K+ content, and alkaloid production in tobacco callus cultures

Abstract

Growth, K+ content, and alkaloid production were compared in nonorganogenetic callus cultures ofNicotiana tabacum cv. Burley 21 grown at 25°C in the dark on two different media: a basal medium with 1 μM α-naphthaleneacetic acid and 1 μM kinetin, and one with 1 μM α-naphthaleneacetic acid and 1 μM 4PU-30 (N-(2-chloro-4-pyridyl)-N′-phenylurea). These callus tissues behaved differently not only in growth and K+ content but also in alkaloid production. In comparison to cultures grown with kinetin, those grown with 4PU-30 showed a significantly higher fresh weight and dry weight and K+ content during the growth period studied. The data clearly indicate a positive correlation between K+ uptake rate stimulated by 4PU-30 and cell enlargement rate. However, the alkaloid biosynthesis in the callus tissues was activated by the supply of kinetin and diminished by that of 4PU-30. It thus appears that cellular enlargement of meristematic tissue stimulated by 4PU-30 limited alkaloid production.