We thank Prof.Eli Zamsky for his advice on plant morphology, Dr.Anat Madmony for her help with endogenous auxin analyses, Dr.Ofer Ovadia for advice on statistical analyses, Dr.Janina Mutchnik for excellent care of the plants,the histological unit of the Pathology Department, Faculty of Health Sciences,Ben-Gurion University of the Negev,for the sections and Dr.Sonia PhilosophHadas for critical reading of the manuscript.