Flower development Induction Signal Competent: Determined xpressed Able to respond in Able to follow same The apical expected manner developmental meristem when given the Photoperiod program even after Hormones undergoes appropriate removal from its morphogenesis developmental normal position sig lant Vegetative growth Flowers A simplified model for floral evocation at the respond to a floral stimulus (induction)by becoming flo shoot apex in which the cells of the vegetative meristem rally determined ( committed to producing a flower). The acquire new developmental fates. To initiate floral develop- determined state is usually expressed, but this may require ment, the cells of the meristem must first become compe- an additional signal (After McDaniel et al. 1992. tent. A competent vegetative meristem is one that can
Flower development
What induces the apex to change from a Two factors that can induce flowering 1. Cold temperature(vernalization). 2. Daylength(photoperiodism)
Two factors that can induce flowering: 1. Cold temperature (vernalization). 2. Daylength (photoperiodism). What induces the apex to change from a vegetative to a flowering state?
Some plants flower in response to cold RIation refers specifica by a period of low temperature. Winter annual (Winter cereal) Winter strains planted in the spring would normally fail to flower Biennials. Biennials are normall flower and die in the second season, again following an overwintering cold treatment In either case. the cold treatment appears to be effective only in the FR 5AM meristematic zones of the shoot pex
Some plants flower in response to cold Vernalization refers specifically to the promotion of flowering by a period of low temperature. Winter annual (Winter cereal): Winter strains planted in the spring would normally fail to flower Biennials:Biennials are normally flower and die in the second season, again following an overwintering cold treatment. In either case, the cold treatment appears to be effective only in the meristematic zones of the shoot apex
Vernalization and de-vernalization Cold Cold temperature Precursor temperature Intermediate Final product product 25~40℃or impropriate daylength treat Degradation It is the shoot apex that receives the signal of De-vernalization cold temperature Vernalization can be removed by other treatments, this phenomena is called de-vernalization
It is the shoot apex that receives the signal of cold temperature. De-vernalization 25~40℃ or impropriate daylength Vernalization can be removed by other treatments, this phenomena is called de-vernalization. Intermediate product Precursor Final product Cold temperature Degradation Vernalization and de-vernalization Cold temperature
Mechanism of vernalization During vernalizaiton Vernalin New proteins(anti-sense inhibition) Change gene expression by demethylation
Mechanism of vernalization During vernalizaiton Vernalin ? New proteins (anti-sense inhibition). Change gene expression by demethylation