The Effect of Ethylene on the Growth and Development of Wild-type and Mutant Arabidopsis thaliana (L.) Heynh

Some developmental responses of wild-type and mutant strainsof Arabidopsis thaliana to ethylene have been investigated (shootand root elongation, isodiametric cell expansion, plumular hookangle, ethylene biosynthesis, peroxidase activity). One suchmutant (eti 5) shows little or no response to ethylene at concentrationsup to 10000 µl 1^–1 in any test; the other mutantsshow reduced responses. The ability of germinated seedlingsto emerge through sand is directly proportional to their sensitivityto ethylene. It is suggested that this finding supports thehypothesis that increased ethylene production in response tomechanical impedance is involved, via its effects on stem thickeningand hook closure, in the emergence process. Arabidopsis thaliana (L.) Heynh., ethylene insensitive mutants, seedling emergence