Mise au point d'un modèle de développement et de tubérisation contrôlés et synchrones chez la Pomme de terre cultivéein vitro

Abstract

Resume.-Pour faciliter l'etude des differentes etapes de Ia croissance et de Ia tuberisation chez Ia pomme de terre, un modele de developpement synchrone a ete mis au point in vitro a partir de fragments uninodaux de tiges. Pour y parvenir, seuls les facteurs de l'environnement physique et nutritionnel ont ete modifies, en absence de tout regulateur de croissance exogene pouvant perturber les teneurs ou activites de substances endogenes, recherchees par Ia suite comme marqueurs des etapes de Ia tuberisation. Le preconditionnement des plantes-mere, le niveau d'origine de I' explant, les photo-et thermoperiodes et les teneurs en azote et en sucre des milieux de culture sont des facteurs essentiels du conditionnement permettant d'optimiser et de synchroniser Ia tuberisation de Ia pomme de terre in vitro.Summary.-In order to study the different steps of the growth and of the tuberization process in potato, a synchronous development model was achieved in vitro from uninodal stem fragments. This result was obtained by only modifying the physical and nutritional factors of the environment. No growth regulator was added to any culture medium in order to avoid any modification in the content level or activity of endogenous substances which could be further analysed as key factors in the tuberization process. The mother plant preconditioning, the origin level of the explant, the photo and thermoperiod as the nitrogen and sugar content of the culture medium are essential factors to take into account in order to optimize and synchronize the in vitro tuberization process.

Defeated Stacked Resistance Genes Induce a Delay in Disease Manifestation in the Pathosystem Solanum tuberosum—Phytophthora infestans

“…After a four-week elongation period, they were introduced into the microtuberization medium in the growth chamber for a period of 8 weeks in total darkness. The medium used for microtuberization is the solid MS medium to which a cytokinin (notably 6-benzylaminopurine (BAP)) recommended by different authors [32][33][34] which stimulates microtuberization and a high concentration of sucrose was added [35]. In our experiment, the quantities added to the MS medium were 80 g/L of sucrose and 2.5 mg/L of BAP.…”

Environmental, morphological and physiological factors analyzes for optimization of potato (<i>Solanum tuberosum</i> L.) microtuber <i>in vitro</i> germination

“…With the same morphology, it is difficult to determine the physiological age of a classic tuber, especially at precocious early stages. In comparison, the reproducibility and synchronous nature of the initiation and in vitro tuberization allow a precise definition of the tuber growth stage [1]. Produced in an aseptic environment, microtubers represent a possible alternative for the production of potato seeds to overcome phytosanitary problems.…”

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

“…Afin de mieux definir les differentes phases du developpement menant a Ia tuberisation chez Ia pomme de terre (Solanum tuberosum L.), nous avons mis au point un modele de developpement et de tuberisation synchrones in vitro, par le seul controle des conditions de milieu et d' environnement (photoperiode, thermoperiode, valeur d'eclairement) des plantes-meres d'une part, puis des explants nodaux destines a tuberiser d' autre part, et ceci en I' absence de tout regulateur de croissance exogene pouvant masquer certaines etapes du developpement (Charles et al, 1995 Pour le dosage enzymatique du fructose, le melange suivant est directement realise dans des micro-cuves contenant un volume final de 500 ~I : -Substrat (30°C) (460 ~I) + melange A (ATP 1 mM + NAD 1mM) (10 ~I)+ melange E (HK, PGI, G5PDH: 2, 2 et 1 unite) (5 ~I)+ extrait dessale (20 ~I) La ligne de base est enregistree durant 3 minutes a 340 nm.…”