Conditions d'apparition d'une embryogénèse somatique sur des cals issus de la culture de tissus foliaires du chêne vert (Quercus ilex)

Abstract

The proliferation of parenchymatous foliar tissue of Quercus ilex was obtained from current year leaves taken from old trees and cultivated in vitro on modified Murashige and Skoog's medium supplemented with benzylaminopurine (4 mg ∙ L−1) and naphthyl acetic acid (0.5 mg ∙ L−1). Only the fragments cultured in October reacted. The neoformations only appeared on calluses that had not been subcultured for 7 months. Primary nodules arising on these calluses were removed and subcultured on the same medium either in the dark or in the light. In the dark only, they produced secondary nodules, which were the source of somatic embryos both in light and dark. Presently, they seem to regulate their structure in the dark but they do not develop in a way that leads to germination.

Application of biotechnological tools to Quercus improvement

“…Overall, these results suggest that leaf tissues are suitable explants for initiating SE in mature trees in different Quercus species, although pedunculate oak appears to be more recalcitrant than cork oak and white oak and the results obtained with the former closely resemble those obtained in leaf explants of a 50-year-old Q. ilex tree (Féraud-Keller and Espagnac 1989). Even in the case of shoot tip explants, the apical meristem itself generally senesced and died during culture, and the basal leaf primordia attached to the axial zone were the real source of generating calluses and, subsequently, embryogenic tissues.…”

Quercus spp. (Oak): In Vitro Culture and Production of Tannins

“…petraea, Q. robur, Chalupa 1990;Q. pubescens, Q. suber, EI Maataoui and Espagnac 1987;Feraud-Keller et al 1989), but also from stem explants of young seedlings (Q. suber, Feraud-Keller et al 1989) and pieces of leaf blades taken from mature trees (Q. ilex, Feraud-Keller and Espagnac 1989).…”

Embryogenesis in Quercus petraea

“…(Sasaki et al, 1988), Q petraea (Jörgensen, 1990), Q rubra (Gingas and Lineberger, 1989) and Q robur (Chalupa, 1990), somatic embryos were observed, but they are only of scientific interest, because they were induced on zygotic embryos, which means on genetically indefinite material. Only Feraud-Keller and Espagnac (1989) with Q ilex and Jörgensen (1988Jörgensen ( , 1990 with Q petraea could induce somatic embryogenesis with tissues of adult trees.…”