Auxin Effect on Protoplasts from Gravireacting Maize Roots

Maize root protoplasts respond to IAA by bursting and the number of surviving protoplasts decreases with increasing IAA concentration. The disruption of the plasmalemma of protoplasts deriving from root cells pretreated by IAA is less. When protoplasts are prepared from the upper and lower parts of the extending zone of gravireacting roots, a higher number of protoplasts from the lower side «survive» in the presence of IAA. This suggests that the content of endogenous IAA of the lower cells is larger than that of the upper cells.