Embryogenèse somatique du cocotier (Cocos nucifera L.) à partir d'explants foliaires: étude histologique

Abstract

Requ le 28 janvier 1991 BUFFARD-MOREL, J., VERDEIL, J.-L., et PANNETIER, C. 1992. Embryogenbse somatique du cocotier (Cocos nucifera L.) a partir d'explants foliaires : Ctude histologique. Can. J. Bot. 70 : 735-741. Une Ctude histologique a Ct C rCaliste aux diffkrentes Ctapes de l'embryogenbse somatique du cocotier (Cocos nucifera L.) i partir d'explants foliaires. Elle a permis de localiser les premibres divisions cellulaires au niveau des cellules pCrivasculaires des explants. La croissance des cals nodulaires obtenus est assurCe par la mise en place d'une assise mCristCmatique a fonctionnement de type cambial. La nature racinaire de certaines formations a t t t observCe. Des structures embryogbnes peuvent apparaitre sur les cals nodulaires; entibrement mCristCmatiques au depart, elles ~'Cpidermisent et se multiplient pour la plupart. Leur Cvolution peut conduire i des structures de type embryon aprks fragmentation et contagion mitotique au niveau de l'assise de type cambial. Ce schema general d'obtention de structures embryonnaires peut cependant varier : (i) Soit il y a obtention rapide d'embryons a partir des cals nodulaires primaires. Cette voie a permis la rCgCntration, par embryogenbse secondaire, d'un massif d'embryons (bourgeonnement au p61e racinaire). L'un d'entre eux a dCveloppC une pousse feuillCe et des racines. La plante rCgCnCrCe a Ct C transfCrCe en champ. (i) Soit il y a formation de cals granuleux secondaires et production de f a~o n plus systtmatique de structures embryogbnes. Ces derniers devraient permettre une meilleure maitrise du dCveloppement des structures embryonnaires. Mots c l b : Cocos nucifera L., histologie, embryogenbse somatique, explants foliaires. BUFFARD-MOREL, J., VERDEIL, J.-L., and PANNETIER, C. 1992. Embryogenkse somatique du cocotier (Cocos rz~rcifera L.) a partir d'explants foliaires : Ctude histologique. Can. J. Bot. 70: 735 -74 1.Histological studies were carried out at different stages of somatic embryogenesis of coconut (Cocos nucifera L.) from leaf explants. The primary formations resulted from mitotic divisions of perivascular cells. Differentiation of a cambium-like layer insured the growth of nodular calluses. The root origin of some formations was observed. Embryogenic structures appeared on some nodular calluses maintained in culture; initially they were highly meristematic and often developed an epidermis and divided. Then embryo-like formations could be obtained after fragmentation of the cambium-like layer producing meristematic areas. However, modifications of this scheme could be observed: ( i ) Embryos rapidly developed from a primary callus, and from these embryos, a secondary embryogenesis was induced leading, at the root pole, to a clump of somatic embryos. One of the latter developed a shoot and roots; the regenerated plant was then transferred to the field. (ii) Secondary granulous calluses producing larger quantities of embryogenic structures were formed. This material should prove useful for mastering the technique of developing embryogenic stru...

In vitro somatic embryogenesis and adventitious root initiation have a common origin in eggplant (Solanum melongena L.)

“…A similar pattern in the cambiumlike zone of nodular callus derived from perivascular cells, has been described by other authors (Ozias-Akins & Vasil 1982, Ho & Vasil 1983, Schwendiman et al 1988, Buffard-Morel et al 1992, Guerra & Handro 1998. The distal region is formed by potentially detachable cells, either by being converted in somatic embryos or by being exfoliated in root caps.…”

“…A similar behavior was reported by Haccius (1978) who observed embryo formation both indirectly from proembryonic cell complexes and directly from single cells. PEMs can be considered as an equivalent of an embryogenic callus in accordance with the results of Ho & Vasil (1983); Schwendiman et al (1988) as well as Buffard-Morel et al (1992) and thus a pathway to indirect embryogenesis.…”

“…Buffard-Morel et al (1992) have proposed that the same growth regulator could induce roots and somatic embryos from coconut. However, direct evidence of the common origin of somatic embryos and adventitious roots has not been provided.…”

“…Histological analysis performed in several plant species showed that somatic embryo development may occur from epidermal (Hutchinson et al 1996, Newman et al 1996, Sagare et al 1995, parenchymatous (Sagare et al 1995) or vascular cells (Ho & Vasil 1983, Schwendiman et al 1988, Buffard-Morel et al 1992, van Hengel et al 1998, Guerra & Handro 1998. Eggplant somatic embryogenesis studies using different growth regulators and various explants including leaves (Gleddie et al 1983, Fillipone & Lurquin 1989, Rao & Singh 1991, cotyledons (Saito & Nishimura 1994), zygotic embryos (Yamada et al 1967) and hypocotyls (Matsuoka & Hinata 1979) have been reported.…”

Meios de cultura, reguladores de crescimento e fontes de nitrogênio na regulação da calogênese do pau-brasil (Caesalpinia echinata Lam.)

“…A semelhança entre esses tipos de calos está na origem. Tantos os calos nodulares quanto os friáveis podem ser formados da atividade das células do procâmbio (Buffard-Morel et al 1992) ou da bainha perivascular (Gueye et al 2009). Essas alterações no programa morfogenético são mais difíceis de serem controladas em espécies arbóreas em função da elevada presença de substâncias oxidativas (Preece 2008).…”