This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Beyer, E. M. Search for Related Content PubMed PubMed Citation Articles by Beyer, E. M., Jr. Agricola Articles by Beyer, E. M.

Articles

Abscission

Support for a Role of Ethylene Modification of Auxin Transport ¹

^a Central Research Department, Experimental Station, E. I. du Pont de Nemours and Company, Wilmington, Delaware 19898

Three types of whole plant experiments are presented to substantiate the concept that an important function of ethylene in abscission is to reduce the transport of auxin from the leaf to the abscission zone. (a) The inhibitory effect of ethylene on auxin transport, like ethylene-stimulated abscission, persists only as long as the gas is continuously present. Cotton (Gossypium hirsutum L. cv. Stoneville 213) and bean (Phaseolus vulgaris L. cv. Resistant Black Valentine) plants placed in 14 µl/l of ethylene for 24 or 48 hours showed an increase in leaf abscission and a reduced capacity to transport auxin; but when returned to air, auxin transport gradually increased and abscission ceased. (b) Ethylene-induced abscission and auxin transport inhibition show similar sensitivities to temperature. A 24-hour exposure of cotton plants to 14 µl/l of ethylene at 8 C resulted in no abscission and no significant inhibition of auxin transport. Increasing the temperature during ethylene treatment resulted in a progressively greater reduction in auxin transport with abscission occurring at [unk]27 C where auxin transport was inhibited over 70%. (c) Auxin pretreatment reduced both ethylene-induced abscission and auxin transport inhibition. No abscission occurred, and auxin transport was inhibited only 18% in cotton plants which were pretreated with 250 mg/l of naphthalene acetic acid and then placed in 14 µl/l of ethylene for 24 hours. In contrast, over 30% abscission occurred, and auxin transport was inhibited 58% in the corresponding control plants.

Collectively, the results presented here and elsewhere indicate that ethylene regulates the sensitivity of the cells in the abscission zone to the more direct actions of the gas (e.g., enzyme induction, secretion) by reducing auxin transport.

This article has been cited by other articles:

				M. K. Pedersen, J. D. Burton, and H. D. Coble Effect of Cyclanilide, Ethephon, Auxin Transport Inhibitors, and Temperature on Whole Plant Defoliation Crop Sci., June 20, 2006; 46(4): 1666 - 1672. [Abstract] [Full Text] [PDF]