Planta, Berlin (1968), 80, 227-236
by Rupert Sheldrake, D.H. Northcote

Autolysing plant tissues are known to produce auxin when extracted with ether. It has been shown that autolysing plant, yeast and rat liver tissues produce auxin in vitro; this suggests that relatively unspecific mechanisms are involved. Furthermore, sterile plant and animal tissues which have been killed by freezing and thawing induce nodules of differentiated cells in a previously undifferentiated callus of Phaseolus vulgaris. The callus tissue is known to differentiate in response to applied gradients of auxin. Plant and animal tissues killed by boiling were considerably less effective in inducing differentiation in the tissue. The evidence indicates that auxin is a normal product of autolysing cells. It is suggested that dying cells are an important source of auxin in the plant.