Banda, Eric , Roden, Laura C. .
Expression of CO and FT during floral induction and reversion in response to photoperiod in Impatiens balsamina.
Flowering in many plants is affected by changes in daylength, or photoperiod, according to the seasons. Floral induction is usually irreversible. The basis for photoperiodic time measurement is endogenous circadian rhythms. We are studying Impatiens balsamina to characterize its photoperiod response pathway and identify the mobile signal involved in floral induction and maintenance because of its natural variation in floral maintenance/reversion. Red-flowered I. balsamina revert to vegetative growth when transferred from florally inductive short-day conditions to inhibitory long-day conditions, whereas purple-flowered I. balsamina are able to continue floral development upon the same transfer (Battey & Lyndon, 1990). It has been proposed that the floral stimulus is of a more permanent nature in purple-flowered than in red-flowered plants (Tooke et al. 1998). Photoperiodic flowering in Arabidopsis is mediated through the circadian clock and light interactions with rhythmically expressed proteins, importantly a transcription factor called CONSTANS (CO) which is expressed in the leaves. When CO interacts with light in long-day plants it is able to activate the transcription of FLOWERING LOCUS T (FT) which initiates the floral transition at the shoot apex. Increased expression of FT is crucial for flowering in both long-day and short-day plants and FT message is proposed to travel from the leaves in the phloem to initiate the floral transition at the shoot apex. We are comparing the expression profiles in leaves of CO and FT orthologues in red-flowered and purple-flowered I. balsamina under inductive, non-inductive and reverting photoperiods.
Battey, N & Lyndon, RF (1990) Botanical Rev. 56, 162-189
Tooke, F, Pouteau, S & Battey, N (1998) J. Exp. Bot. 49, 1681-1688
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1 - University of Cape Town, Molecular and Cell Biology
2 - University of Cape Town, Molecular and Cell Biology, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM