Auxin control of calcium-mediated peroxidase secretion by auxin-dependent and auxin-independent sugarbeet cells

Peroxidase secretion by three sugarbeet cell lines in the absence of Ca2+ was unaffected by the addition of auxins of different chemical structures. The six auxins tested had no effect on the Ca2+ -promoted peroxidase secretion by habituated non-organogenic cells (HNO), but they enhanced the secretion by normal non-organogenic cells (NNO) and three of them inhibited it in the case of the habituated organogenic line. A 5-week subculture of the auxinindependent HNO callus on auxin-containing media increased the sensitivity of cells to Ca2+ and their responsiveness to auxins in suspension cultures. Conversely, subculture of the auxin-requiring NNO callus on auxin-deficient medium induced a decreased sensitivity to Ca2+ and a complete loss of response to auxins. The possible regulation of peroxidase secretion by Ca2+- and auxin-receptors is discussed. © 1983.