In Vitro Culture of Rudimentary Embryos of Ilex paraguariensis: Responses to Exogenous Cytokinins

Abstract

The effects of benzyladenine (BAP), kinetin (KIN), zeatin (ZEA), isopentenyladenine (2iP), and thidiazuron (TDZ) were studied on in vitro growth of rudimentary embryos of Ilex paraguariensis St. Hil. Heart stage zygotic embryos were removed from seeds of immature, light green fruits and cultured aseptically on quarter-strength Murashige and Skoog medium containing 3% sucrose, 0.65% agar, and supplemented with or without three concentrations of BAP, KIN, ZEA, 2iP, or TDZ. Cultures were incubated in darkness at 27 ± 2°C. Media containing 4.4 × 10 −6 M BAP, 4.6 × 10 −6 M KIN, or 4.9 × 10 −6 M 2iP were totally ineffective in inducing embryo growth after culture for 28 days. However, lower concentrations of these compounds (4.4 × 10 −8 M BAP, 4.6 × 10 −8 M KIN, 4.5 × 10 −8 M ZEA, or 4.9 × 10 −8 M 2iP) promoted embryo growth. TDZ at 9.9 × 10 −9 M, 9.9 × 10 −8 M, or 9.9 × 10 −7 M induced embryo growth at similar rates. The maximum percentage of embryos converted to seedlings was achieved when the medium was supplemented with 4.5 × 10 −7 M ZEA.

Micropropagation of chestnut rose (Rosa roxburghiiTratt) and assessment of genetic stability inin vitroplants using RAPD and AFLP markers

“…Shoots produced in the control, and in treatments supplemented with BA, or both BA and AC, were vigourous. Shoots regenerated on media supplemented with TDZ showed hypertrophic leaf development and moderate vigour, which has also been reported in other species (Beattie and Garret, 1995;Sansberro et al, 1998).…”

Micropropagação de plântulas de erva-mate obtidas de embriões zigóticos

“…As mudas comerciais de erva-mate são produzidas a partir de sementes (WENDLING, 2004), de baixa qualidade genética, física e fisiológica (STURION, 1988). Além disso, as sementes das espécies do gênero Ilex apresentam dormência embrionária, que dificulta o processo de produção de mudas (SANSBERRO et al, 1998;CARVALHO, 2003), sendo necessário um período de estratificação em areia, por um período de cinco a seis meses (ZANON, 1988;FOWLER & STURION, 2000).…”

Plant regeneration from immature zygotic embryos of chestnut rose (Rosa roxburghiiTratt) through organogenesis

“…In contrast, shoots that regenerated on media with BA were taller. There have been reports that exogenous cytokinins are not a prerequisite for embryo maturation (Sansberro et al, 1998). In the present work, a cytokinin was necessary for shoot regeneration during the early cotyledonary stage of chestnut rose embryos which were not yet able to germinate.…”

“…An efficient in vitro regeneration protocol from immature zygotic embryos would have great potential for shortening the time otherwise required to obtain F 1 -hybrid seedlings by sexual crossing, and for enhancing the efficiency of hybrid production, especially in widecrosses within the genus. This strategy has been welldocumented for a wide range of plant species (Sansberro et al, 1998;Phillip et al, 2001;Polanco and Ruiz, 2001;Troncoso et al, 2003).…”