The role of the epidermis in auxin induced and fusicoccin induced elongation of pisum sativum cultivar alaska stem segments
Brummell, D.A.; Hall, J.L.
Planta (Heidelberg) 150(5): 371-379
ISSN/ISBN: 0032-0935 Accession: 006762302
The effects of peeling and wounding on the IAA and fusicoccin (FC) growth response of etiolated P. sativum L. cv. Alaska stem tissue were examined. Over a 5 h growth period, peeling virtually eliminated the IAA response but .apprx. 30% of the FC response remained. Unpeeled segments wounded with 6 vertical slits exhibited significant responses to both IAA and FC; peeling does not act by damaging the tissue. Microscopy showed that the epidermis was removed intact and that the underlying tissue was essentially undamaged. Neither the addition of 2% sucrose to the incubation medium nor the use of a range of IAA concentrations down to 10-8 M restored IAA-induced growth in peeled segments; lack of osmotic solutes and supra-optimal uptake of IAA apparently were not important factors over this time period. Although the possibility remains that peeling merely allows leakage of H ions into the medium, peeling off the epidermis probably removes the auxin responsive tissue.