[Levels of hydroxycinnamic acids and free auxins in tobacco during photoperiodic induction].

The photoperiod controls hydroxycinnamic acids (involved in light signal transmission via interaction with the control proteins) in addition to plant hormones in tobaccos of different biotypes during the vegetative-to-reproductive switch of the genetic program. Hydroxycinnamic acids content shows a regular time pattern during the transition to flowering: the level of cinnamic acid decreases while the level of ferulic and chlorogenic acids increases despite the opposite photoperiodic response of the two tobaccos. Considering the possible use of hydroxycinnamic acids in light energy transduction, one can propose involving these substances in the reactions that induce plant flowering.