Adventitious root formation in Arabidopsis thaliana thin cell layers.

This paper describes, for the first time, de novo adventitious root formation from thin cell layers (TCLs) of Arabidopsis thaliana. The objective of the study was to determine the optimal hormonal and light conditions and the optimal exogenous Ca2+ concentration for obtaining adventitious rooting (AR) from A. thaliana TCLs and to identify the tissue(s) involved in the process. The results show that maximum AR was obtained with a single-phase method in the presence of 10 microM indole-3-butyric acid and 0.1 microM kinetin under continuous darkness for 30 days and with 0.6 mM exogenous CaCl2. The endodermis was the only tissue involved in root meristemoid formation. The role of Ca2+ in AR and the importance of using Arabidopsis TCLs in studies on the genetic/biochemical control of AR are discussed.