The effect of culture medium formulation on Pinus nigra somatic embryogenesis

Abstract

Abstract:The potential of immature zygotic embryos to produce embryogenic tissue was tested using culture media differed in inorganic salt composition as well as plant growth regulator content. Explants cultured on DCR as well as MLV media gave the highest initiation percentages with maximum values of 8.8% (MLV) to 10.4% (DCR). Plant growth regulators content (standard or reduced) had no profound effect on embryogenic tissue initiation. Somatic embryo maturation as well as germination was dependent on the cell line and salt composition of the medium. Plantlet regeneration occurred in three cell lines out of five tested. During the maturation process profound changes occurred in the internal organisation of somatic embryos such differentiation of root meristem in precotyledonary somatic embryos and formation of provascular strands in cotyledonary somatic embryos.

Bottlenecks in bog pine multiplication by somatic embryogenesis and their visualization with the environmental scanning electron microscope

“…In most pine species, initiation of embryogenic cultures is limited to the first period of zygotic embryo development during the cleavage stage or prior to the development of the cotyledons. Our results are in agreement with results reported on several Pinus species (Klimaszewska et al 2001;Lelu-Walter et al 2008;Hargreaves et al 2009;Carneros et al 2009;Montalbán et al 2012;Salaj et al 2014). In order to obtain cotyledonary somatic embryos, all induced cell lines were tested for their maturation abilities (data not shown).…”

“…From previous reports of SE in Pinus spp., it was found that the most responsive media is DCR (Gupta and Durzan 1985) with/without small modifications (Miguel et al 2004;Aronen et al 2009;De Diego et al 2010;Montalbán et al 2013). Similar concentrations of plant growth regulators (PGR) were tested in Pinus nigra where the best initiation response was also achieved (Salaj et al 2014). Conversely, Klimaszewska et al (2001), in experiments with Pinus strobus, have found that with decreasing the concentration of PGR, initiation frequencies were increased from 20 to 53 %.…”

“…As mentioned previously, initiation frequency in bog pine was very low, only 0.95 %. Low initiation frequency was reported in several studied species in the genus Pinus, e.g., in P. sibirica, 0.2-0.5 % (Tret'yakova and Voroshilova 2014); in P. pinea, from 0.5 to 7.2 % (Carneros et al 2009); in Pinus armandii across nine open-pollinated families, initiation frequency ranged from 0 to 20 % with an average of 1.5 % (Maruyama et al 2007); in Pinus nigra (maximum 10.3 and 10.4 %) (Salaj et al 2014); in Pinus sylvestris, the initiation frequencies varied from 0 to 26.7 % (Aronen et al 2009); for Pinus radiata with 55 % initiation frequency on average (Hargreaves et al 2009); and 20-53 % for Pinus strobus (Klimaszewska et al 2001). Low initiation frequencies are often obtained because many desired seed sources are recalcitrant and tissue survival is often poor (Pullman et al 2009).…”

“…Maltose in a concentration of 6 % was a significantly better carbohydrate source for bog pine in comparison with sucrose. It might be because maltose has a slower break down and thus provides longer-lasting high osmolarity required for maturation (Salaj et al 2014). Maltose was reported as the dominant metabolite in late embryogeny of P. abies embryogenic line producing normal somatic embryos; about half of this level was recorded in a line producing aberrant embryos, but in the line producing no embryos, only a low level of isomaltose and no maltose was detected (Businge et al 2012).…”

Conifer somatic embryogenesis – an efficient plant regeneration system for theoretical studies and mass propagation

“…The initiation frequencies have been variable depending on the species, year of cones harvest, developmental stage of zygotic embryos, nutrient medium composition reaching values in average 20% for Pinus pinaster (Humanez et al 2012), 5-50% for Juniperus communis (Helmersson and von Arnold 2009), 5% for Pinus taeda (Becwar et al 1990), 2.1-10.3% for Pinus nigra Salaj et al (2014) and 20.6% for Pinus radiata (Montalbán et al 2012).…”