SIGNAL MOLECULES INVOLVED IN PLANT EMBRYOGENESIS

In plant embryogenesis, inductive interactions mediated by diffusable signal molecules are most likely of great importance. Evidence has bee n presented that at late globular stages in plant embryogenesis, pertu rbation of the polar auxin transport results in abberrant embryo morph ology. Rhizobium lipooligosaccharides or Nod factors are a newly disco vered class of bacterial molecules that are able to trigger initial st eps in root nodule development in legumes. Part of the activity of Nod factors may be directed towards alteration of endogenous plant growth regulator balance. The same bacterial Nod factors promoted the format ion of globular embryos in the carrot cell line ts11. Whether there ex ist plant analogues of the Nod factors and whether these molecules are active as a more universal control system perhaps designed to initiat e and or mediate gradients in auxin and cytokinin remains to be determ ined.