A new approach to direct somatic embryogenesis in Medicago

Abstract

A highly efficient system for direct somatic embryogenesis is described. Leaf sections originating from young trifoliate leaves of Medicago falcata line 47/1-5 and Medicago sativa line No2/9R, directly produced embryos after cultivation in liquid B5IV induction medium. In comparison with indirect somatic embryogenesis the system omits the callus stage and thus allows shortening of the process of somatic embryogenesis in alfalfa by 35-40 days. It permits the avoidance of secondary changes occurring during the process of dedifferentiation. A modified B5/3H medium containing Polyethylene Glycol 6000 promoted embryo development from globular up to torpedo stage. It was clearly shown that 2.5% Polyethylene Glycol stimulated this process for both H. falcata 47/1-5 and M. sativa No 2/9R. Maturation of torpedo stage embryos was carried out on solidified or liquid abscisic acidcontaining medium. A 30μM abscisic acid concentration was optimal in allowing one embryo to yield one plant. Somatic embryo conversion to plants and plant regeneration was performed on Murashige and Skoog medium. Regenerated plants showed a normal morphology.

Variability of somatic embryogenic ability in the genus Pisum L: effects of genotype, explant source and culture medium

“…The stimulation of somatic embryogenesis in shoot apex or immature cotyledon caused by substituting fructose or maltose to sucrose as previously shown with Cl 830 (Loiseau et al, 1995), was confirmed here with 22 (Finer, 1987), Panax ginseng (CA Meyer) (Asaka et al, 1994) and for somatic embryo development in Picea mariana (Mill) BSP and Picea rubens Sarg (Tremblay and Tremblay, 1991). Sugars have acted as osmotic agent, at least in part, when their concentrations were high (Denchev et al, 1991;Tremblay and Tremblay, 1991 (Loiseau et al, 1995). In addition, sucrose, fructose or glucose at 168 mM reduced the production of somatic embryos compared to maltose at the same concentration in culture of immature cotyledons (Loiseau, 1996).…”

Phaseolus Vulgaris L. Somatic Embryos Induction in Liquid Medium

“…That media was successfully 11 used for Medicago sp. embryo development (8). Good results were also obtained for bean, but it was necessary the media to be optimized.…”

“…Next step was to transfer the embryos for l-2 weeks on solidified MS medium (15) supplemented with 10; 20; 30 and 40 ~tM ABA and 3 g gelrite for the maturation (8).…”

Establishment of Embryogenic Potential of Economically Important Bulgarian Alfalfa Cultivars (Medicago SativaL.)

“…Among the auxins, the embryogenic effect of 2,4D is well known in legumes (2) and especially in genera Medic ago (32,10,17).…”