Growth and nicotine content of tobacco callus cultures without organogenesis

Growth and nicotine production were measured in callus tissue without organogenesis, derived from the petiole of Nicotiana tabacum L. cv. Burley 21 cultured on Murashige-Skoog medium (MS medium), T. Murashige and F. Skoog, Physiol. Plant., 15 (1962) 473, containing auxin α-naphthaleneacetic acid (NAA) and kinetin,at 25°C in the dark. Experiments clearly demonstrated that in the presence of a constant amount of kinetin, it is the auxin concentration in the culture medium that controls the rate of nicotine synthesis which follows a course almost parallel to callus growth. The maximum accumulation of nicotine in the callus (0.16% of dry wt.) is slightly higher than in the intact plant. A cytological examination of the callus tissue showed that the greater degree of cellular differentiation which causes the loss of meristematic areas, inhibits alkaloid synthesis.