The role of gibberellins in embryo axis development.
The role of gibberellins (GAs) during early embryo development was examined using microspore-derived embryos (MDEs) of Brassica napus. At the globular stage of development, 10 d after initial culture (DAC) when endogenous GA(1) levels are increasing rapidly, a triazole, uniconazole, was used at 1, 33 and 100 microM to inhibit GA biosynthesis. Within this dose range there was no apparent effect of the inhibitor on embryo growth through to the early torpedo stage. However, by 25 DAC uniconazole-treated MDEs showed significantly reduced (50%) axis elongation. Addition of GA(1) at 33 microM on 14 DAC to embryos pretreated with 1 microM uniconazole on 10 DAC prevented this reduction in axis length, giving axis elongation equivalent to untreated MDEs. Application of GA(1) alone, however, did not significantly increase axis elongation. The reduced axis growth seen with uniconazole treatment was due to reduced cell elongation, but not cell number, and the co-applied GA(1) thus prevented the uniconazole-induced reduction in cell length. The elongating axis of MDEs may thus be a useful tool for examining the role of GAs in cell elongation.
Hays
Dirk B
DB
Plant Physiology Research Group, Department of Biological Sciences, 2500 University Drive NW, University of Calgary, Calgary, Alberta, Canada T2N IN4. dbhays@ag.tamu.edu
Yeung
Edward C
EC
Pharis
Richard P
RP
D029688:Brassica napus / Q000187:drug effects / Q000254:growth & development; D004305:Dose-Response Relationship, Drug; D005875:Gibberellins / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D012639:Seeds / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D013997:Time Factors; D014230:Triazoles / Q000494:pharmacology
D005875:Gibberellins; D014230:Triazoles; C092705:uniconazole