Exposure of Petunia Seedlings to Ethylene Decreased Apical Dominance by Reducing the Ratio of Auxin to Cytokinin |
| |
Authors: | Darren L Haver Ursula K Schuch Carol J Lovatt |
| |
Institution: | (1) Department of Botany & Plant Sciences, University of California, Riverside, 92521-0124 California, USA;(2) Department of Plant Sciences, University Arizona, Tucson, 85721-0036 Arizona, USA |
| |
Abstract: | Seedlings of Petunia x hybrida ‘Orchid’ treated with the ethylene-releasing compound ethephon at 0.9, 1.7, and 3.5 mM evolved ethylene at a higher rate as the concentration of ethephon increased. Regardless of the concentration of ethephon applied, ethylene evolution peaked 6 to 8 h following application. Evidence that ethephon application decreased apical dominance included an increase in the number of new nodes on the main stem and a sustained increase in the length of new and existing lateral shoots compared to the control (no ethephon). Plants treated with 3.5 mM ethephon developed mild chlorosis, whereas a concentration of 1.7 mM ethephon decreased apical dominance without phytotoxic effects. The auxin/cytokinin ratio decreased in the apical shoot section as early as 1 h after ethephon treatment. In contrast, a decrease in the ratio in the subapical shoot section was not detected until 24 h after ethephon application. Reduction in auxin/cytokinin ratio was a result of a decrease in indole-3-acetic acid (IAA) and an increase of zeatin riboside (ZR), but not isopentenyladenosine (iPA). These results suggest that exposing ‘Orchid’ petunia seedlings to ethylene via ethephon lowers the auxin/cytokinin ratio, thereby promoting the outgrowth of lateral shoots. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|