Relationship between hormone content and autonomy in various autonomous tobacco cells cultured in suspension

Abstract

Various autonomous cultured tobacco cells including crown gall were examined for their contents of growth regulators by means of Avena curvature test, cell-division induction test, and tobacco pith callus test. The crown gall cells derived from cv. Hicks produced auxin and cytokinin in the high levels of 300–500 μg IAA equivalents and 40–80 μg kinetin equivalents per kg, respectively. The major auxin was identified as indole-3-acetic acid based on mass spectrometry and gas chromatography. These cells also produced methyl indole-3-acetate as a minor component. One of the cytokinins was identified as ribosyl-trans-zeatin by means of both gas chromatography-mass spectrometry and high performance liquid chromatography. Auxin and cytokinin activities were not detected in the following three suspension cultured tobacco cells: cells requiring neither cytokinin nor auxin derived from the callus of N. tabacum cv. Bright Yellow and cells requiring auxin but not cytokinin derived from the calluses of cv. Bright Yellow and cv. Hicks. Their auxin and cytokinin contents per kg were less than 1 μg IAA equivalent and less than 0.1 μg kinetin equivalent, respectively. The results obtained in this study indicate that enhanced hormonal content is not the only reason for autonomous growth.