Applications d'un modèle de développement et de tubérisation synchrones chez la Pomme de terre cultivéein vitro. Evolution d'activités enzymatiques

Abstract

Resume.-Dans cette etude a ete applique un modele de developpement et de tuberisation synchrones, obtenu a partir d'explants uninodaux chez Ia Pomme de terre cultivee in vitro, en absence de tout regulateur de croissance. Les parties superieures et basales des tiges de ces plantes, prelevees au cours du temps, ont ete dosees pour leur teneur en proteines solubles et leurs activites invertase et saccharose synthase. L'activite invertase, utilisee comme marqueur de l'activite metabolique de Ia plante, est nettement accrue dans Ia partie superieure des tiges chez les plantes induites en jours courts, particulierement avec thermoperiode. Cette activite importante peut traduire une amplification du metabolisme des sucres, que nous avons associee a une etape de preinduction de Ia plante. L'activite saccharose synthase s'exprime de fa<;on ponctuelle au niveau des tubercules en cours de remplissage.Summary.-In this study was used a model of synchronous development and tuberization, obtained in vitro from uninodal stem fragments of potato, without adding any exogenous growth regulator. Upper and basal parts of the stems were sampled at different times and analysed for their soluble protein content and for their invertase and sucrose synthase activities. Invertase activity, used as an indicator of the metabolic activity, increased dramatically in the upper part of the stems of plants induced by short days, particularly with a thermoperiod. This high activity could point out an increase of the sugar metabolism which was associated to a preinducting step in the plants. The sucrose synthase activity presents a peak at the tuber level during they are swelling.

Influence of the Size of Potato Microtubers (&lt;i&gt;Solanum tuberosum&lt;/i&gt; L.) on the Yield of Plants under Semi-Axenic Conditions

“…Vitrotubers have a quality advantage conferred by a production carried out in the laboratory, under aseptic conditions, without the possibility of external contamination [3] [4].…”

“…These microtubers can be used as seeds and can be easily transported from one country to another or even from one continent to another by air. Moreover, microtubers and minitubers as well are a possible alternative for the production of potato seeds and to overcome phytosanitary contaminations [3].…”