Changements d'activités métaboliques et induction de la tubérisation in vitro chez la pomme de terre

Summary This work is an attempt to precise the events preceding tuber induction of potato plants in vitro submitted to short days, SD. Enzymatic markers (saccharose activity, I, and peroxydase activity, Per), measuring metabolic sequences taking place during the process, were used for. From the synthesis of our own results and of different anthors ones on the subject, it appears that the "SD effect" leads, as a metabolic stress, to a rapid senility state and to the stem growth stopping. The prime causal effect is a photosynthetic production shortage, mainly in saccharose, a high rate of which (beyond the specific or varietal break-even point) being necessary to make firm both the fixation of AIA on the cell membrane and the ATP reduction. The stress consequence is an adaptative response of potato plants conducting in three successive stages to the tuber induction. The two first stages of the process are discussed on in this paper.