Long-term suspension cultures of cucumber (Cucumis sativus L.) with high embryogenic potential

Abstract

Cucumber (Cucumis sativus L.) cytokininindependent embryogenic cell suspension cultures were derived and maintained for more than 3.5 years without losing the embryogenic potential. The preparation and the characteristics of the cucumber embryogenic cell suspension possess many similarities to that of carrot. The cultures were induced from hypocotyl explants of in vitro grown cucumber plants in liquid MS media containing 2,4-dichlorophenoxyacetic acid as the sole growth regulator during 6 weeks and they contained a heterogeneous array of several different types of single cells and cell clusters (PEMs). The established cell suspensions were subcultured in 1-week interval, while the inoculation density was optimized to 2.0 9 10 5 cells ml -1 using cell viability as a marker. Somatic embryos were obtained after the transfer of the proembryogenic masses to a hormone-free semisolid MS medium with a frequency of 388 ± 57 somatic embryos per 1 ml of packed cell volume of the established cucumber embryogenic culture within 7 days. The frequency of normal somatic embryos with two cotyledons was found to be 78%. Such embryos possessed the potential of spontaneous maturation and the embryo conversion rates were 87%. The yield of normally growing plants was much higher compared with that previously described for cucumber systems. Somatic embryo-derived plants were successfully transferred to the greenhouse where they flowered and fruited.

Influence of osmotic stress, physicochemical factors and nitrogen supplements on embryogenesis and plantlet formation in Guizotia abyssinica Cass. (Niger)

“…The embryogenic potential during the long-term culture gradually decreased in our study. This is comparable with the results of Sarreb et al (2002) and Andrýskova et al (2009) who maintained cell suspensions for more than 2-3 years. One of the approaches for improvements of somatic embryo in 6 months old calli can be elimination of growth regulators after a certain time.…”

“…The induction of somatic embryogenesis has been achieved in several plant species by altering concentration and combination of auxins and cytokinins (Adda et al 1994;Ashok Kumar et al 2000;Ceasar and Ignacimuthu 2010), age of the cultures (Andrýskova et al 2009), osmotic stresses (Groll et al 2002;Zavattieri et al 2010), physiochemical factors (Hofmann et al 2004) and nitrogen sources (Sen et al 2002;Awal et al 2008).…”

Evaluation of somatic embryo production during embryogenic tissue proliferation stage using morphology, maternal genotype, proliferation rate and tissue age of Pinus thunbergii Parl

“…However, assessing SEP by tissue age alone is not accurate, because the degree of ET degeneration is different among genotypes and culture conditions. For example, cucumber (Cucumis sativus L.) maintains its embryogenic potential for more than 3.5 years in cytokininindependent suspension cultures (Andryskova et al 2009). Our results suggested the combination of ET surface morphology, histology (the proportion of the acetocarminestained red area) and variations in physiological characteristics (carbohydrates and enzymatic activities) could be used to precisely assess the ET maturation capacity.…”

Influence of High Concentrations of Copper Sulfate on In Vitro Adventitious Organogenesis of Cucumis sativus L.

“…Regeneration via organogenesis and somatic embryogenesis has been described in this species, and commonly used explants include cotyledons [26][27][28][29], cotyledonary nodes [26,[30][31][32], hypocotyls [27,[33][34][35], shoot tips [36][37][38][39], and leaves [27,37,40,41]. Regeneration of cucumber has also been reported from protoplasts [42][43][44] and suspension cultures [45][46][47]. Cucumber regeneration is largely dependent on genotype, explant type, and culture medium [24,26,34].…”