Evolution of endogenous hormone concentration in embryogenic cultures of carrot during early expression of somatic embryogenesis

Abstract

Embryogenic callus and suspension cultures of carrot (Daucus carota L., cv. Nantaise), growing on/in medium including 1 mg/l 2,4-dichlorophenoxy acetic acid (2,4-D), were transferred to medium with or without this plant growth regulator, to impair or induce, respectively, further development of somatic embryos. The endogenous hormone levels of the cultures were determined over 7 days by means of radio-immunoassay, to characterize their evolution in the initial stages of embryo development. In general, levels of indoleacetic acid (IAA) and abscisic acid (ABA) showed only short-lived differences among treatments during this time in both types of tissue analyzed (i.e., a peak of IAA in callus cultures in the absence of 2,4-D, 48 h after medium change, and higher ABA contents 144 h after subculture of suspension cultures in the presence of 2,4-D). Gibberellins (1, 3 and 20) were detected only in suspension cultures devoid of 2,4-D, starting 24 h after subculture. Concerning the evaluated cytokinins-zeatin/zeatin riboside and N6(Delta2-isopentenyl) adenine/N6(Delta2-isopentenyl) adenosine-the most remarkable observation is that high levels of the former generally coincided with low concentrations of the latter, indicating a shift from precursor to the active form, and vice versa.

Reaction of Flax (Linum Usitatissimum L.) Calli Culture to Supplement of Medium by Carbon Nanoparticles

“…There are no previous studies on the influence of nanoparticles on ploidy level of calli culture. However, optimal culture conditions, medium, type and level of plant growth regulators to induce somatic embryogenesis in different species, have been widely discussed (Komamine et al, 1992;Jimenez, 2001;Jimenez et al, 2005;Park et al, 2011). Obtaining all the developmental stages similar to those of zygotic embryous are exclusive (Hofmann et al, 2004;Korbes and Droste, 2005;Santos et al, 2006;Chitra Devi and Narmathabai, 2011).…”

Involvement of Plant Hormones and Plant Growth Regulators on in vitro Somatic Embryogenesis

“…In a more recent work, Jime´nez et al (2005) analyzed evolution of endogenous IAA, ABA, GAs (GA 1 , 3 , 20 ) and several CKs, during the first 7 days after 2,4-D was removed from the culture medium. They only found minor changes in concentration of the evaluated hormones along time, i.e., a peak of IAA in callus 48 h after 2,4-D removal, and some fluctuations in the CKs, making high levels of zeatin/zeatin riboside to coincide with low concentrations of iP/iPA.…”

Acquisition of callogenic capacity in date palm leaf tissues in response to 2,4-D treatment

“…In addition, levels of endogenous hormones determine the specificity of cellular responses during SE (Féher et al 2003;Jiménez et al 2005). For example in Zea mays and Daucus carota, endogenous indole-3-acetic acid (IAA) concentrations have been found to be higher in embryogenic than non embryogenic cell cultures (Jiménez and Bangerth 2001a, b).…”