Étude histologique de l’embryogenèse somatique de l’olivierOlea europaeacv. Picholine marocaine

Abstract

Histological study of the somatic embryogenesis of Moroccan Picholine olive tree Olea europaea. Abstract-Introduction. The olive-tree (Olea europaea L.) is the principal fruit-bearing species in Morocco. Until now, the somatic embryogenesis of the Picholine olive-tree was very little studied in spite of the importance of this variety in Morocco. We aimed at studying the effects of various culture media on the induction and the development of Picholine somatic embryos. Materials and methods. Whole seed cotyledons of olive-tree were cut after disinfection and explants were put in culture. The embryogenic callus initiation took place on a Murashige and Skoog culture medium, solidified with agar and containing 0.5 mg zeatine•L-1 combined with various concentrations in naphthalene acetic acid (NAA)) [(1, 2, 5, 10 and 40) mg•L-1 ], control cultures being without growth regulators. After 3 weeks, calli were transferred on a medium either liquid, or solidified by agar or gelerite. After 6 weeks on the induction medium, calli were transferred on a medium maintained liquid or solidified by agar or gelerite, and containing 0.5 mg zeatine•L-1 , in order to support the development of the somatic embryos and, thereafter, their regeneration in seedlings. Induced callus rate and formed callus average weight were measured after 6 weeks of culture on the induction medium. A histological comparison was carried out between embryogenic calli and non embryogenic calli. Results. The callus induction was significantly influenced by the concentration in ANA. The best results were obtained with 2 mg ANA•L-1 for the callus induction (82,3%) and 5 mg ANA•L-1 for the callus development (150 mg). The liquid medium proved to be the best for the callus induction and the agar medium supported the callus development and the seedling regeneration by somatic embryogenesis. Gelerite use did not allow any morphogenesis. Regenerated and acclimatized seedlings presented a normal growth in greenhouse. Conclusion. Somatic embryogenesis would be exploitable for the olive-tree micropropagation in Morocco. Morocco / Olea europaea / plant propagation / in vitro culture / micropropagation / somatic embryogenesis / culture media Étude histologique de l'embryogenèse somatique de l'olivier Olea europaea cv. Picholine marocaine. Résumé-Introduction. L'olivier (Olea europaea L.) est la principale espèce fruitière exploitée au Maroc. L'embryogenèse somatique de la Picholine marocaine a été jusqu'à présent très peu étudiée malgré l'importance de cette variété au Maroc. L'objectif de nos recherches a été d'étudier les effets de divers milieux de culture sur l'induction et le développement d'embryons somatiques chez cette variété. Matériel et méthodes. Des cotylédons entiers de graines d'olivier ont été excisés après désinfection et mis en culture. L'initiation des cals embryogènes a eu lieu sur un milieu de culture de Murashige et Skoog, solidifié par de l'agar et contenant 0,5 mg de zéatine•L-1 combinée à différentes concentrations en acide naphtalène acétique (ANA)...

Warm stratification combined with organic manure application enhances seed germination and improves Cycas revoluta growth and development

“…Microscopic observation of zygotic embryos from C and T2 treatments (2 monthsold) was conducted using Epson light microscope equipped with an imag ing software. For that, zygotic embryos were fixed using a mixture of 95°C ethanol and acetic acid (3:1) for 24 hours as described by Brhadda and Abousalim (2007). ZEs were dehydrated by passing through a series of alcohol baths (70°, 95° and 100°C).…”