Influence of Growth Regulators on Callogenesis and Somatic Embryo Development in Date Palm (Phoenix dactyliferaL.) Sahelian Cultivars

Abstract

<jats:p>This study provides a physiological analysis of somatic embryogenesis in four elite cultivars of date palms: Ahmar, Amsekhsi, Tijib, and Amaside, from the initial callogenesis to establishment and proliferation of embryogenic suspension cultures. Somatic embryos development and in vitro plants rooting were also studied. For each step, auxins and cytokinins concentrations were optimised. The primary callogenesis from leaf explants of seedlings appeared highly dependent on genotype. Ahmar (80%) and Amsekhsi (76%) appeared highly callogenic, whereas Tijib (10%) and Amaside (2%) produced low amounts of calluses. 2,4-Dichlorophenoxyacetic acid appeared favorable to the induction of primary callogenesis and its effect was enhanced by the addition of benzyl adenine or adenine sulfate. Secondary friable calli obtained from chopped granular calli were used to initiate embryogenic cell suspensions in media supplied with 2,4-dichlorophenoxyacetic acid. Suspension cultures showed a growth rate of fourfold after four subcultures in presence of 2,4-dichlorophenoxyacetic acid 2 mg/L. Our results showed that a seven-day transitory treatment with benzyl adenine 0,5 mg/L was necessary to optimize embryos development. Naphthalene acetic acid induced the development of primary orthogravitropic roots during embryos germination. The comparison with cytofluorometry of nuclear DNA amounts showed no significant difference in ploidy level between regenerated plants and seedlings.</jats:p>

Induction of direct somatic embryogenesis and callogenesis in date palm (Phoenix dactylifera L.) using leaf explants

“…High callogenesis rates were also obtained in the presence of the combinations of 2,4-D with BA in date palm (Ahmar and Amsekhsi cultivar), which corresponded with our results. It has also been observed that the application of high concentrations of cytokinin caused a reduction of callogenesis (Sane et al, 2012). Vescovi and coworkers (2012) also found that the use of high levels of BA (9 mg/l) induced the apoptosis of the cells in the cultures of Arabidopsis thaliana.…”

Mechanism of Phosphate Solubilization and Physiological Functions of Phosphate-Solubilizing Microorganisms

“…Plant growth regulators (PGRs) are the substances that influence physiological processes of plants at very low concentrations and modify or control one or more specific metabolic events of a plant (Danova et al 2012;Sane et al 2012). According to the Environmental Protection Agency (EPA), the plant regulators have been defined as "any substance or mixture of substances intended, through physiological action, to accelerate or retard the rate of growth or maturation, or otherwise alter the behaviour of plants or their produce".…”

Optimizing rooting and survival of oil palm (Elaeis guineensis) plantlets derived from somatic embryos

“…In the absence of auxins, 58% of rooting occurred after 150 d of cultivation. In E. guineensis and Phoenix dactylifera, shoots derived from embryo multiplication also showed development of roots in auxin-free media, although auxin supplementation favored rooting (Nizam and Te-Chato 2009;Sumaryono and Riyadi;2011;Sané et al 2012). These results likely can be explained by the existence of natural auxins, such as indole-3-acetic acid (IAA), in the tissues of the explants, or by the residual effects of the auxins used in the induction and multiplication phases of the embryogenic cultures (Klerk et al 1999).…”