Embryo rescue in Rosa hybrida L.

Abstract

Two crosses between Rosa hybrida L. cultivars, that fail to produce progenies by conventional means, were carried out. In one of them, total hip abscision occured seven weeks after pollination; in the other one, only 2 % of the fertilized hips remained on the plants after eleven weeks. Four-and five-week-old fertilized ovules were isolated in the first cross and six-week-old embryos in the second. The ovules were cultured on six media which differed in their mineral salt and sucrose concentrations while the embryos were cultured on only one of these media and eventually cold treated for one month at 4 ° C before being placed in a culture room set at 23 ° C. The embryos that had been isolated in ovulo when they were still not visible under a binocular lens developed atypically. The embryos isolated in ovulo when they were heart-shaped and on average 0.27 mm long performed in ovulo germination on some media and/or enlargement on all of them after two weeks; after another two week culture, once isolated from the ovule, all of them germinated. The cultured isolated embryos, that were exposed to cold, enlarged and germinated more rapidly when placed at 23 ° C than those not exposed to cold. Furthermore, the plantlets resulting from untreated embryo germination were characterized by large cotyledons which were only partially green. These results are discussed in regard to embryogenesis, precocious germination and dormancy.

Dynamics of abscisic acid and indole-3-acetic acid during the early-middle stage of seed development in Rosa hybrida

“…In Rosa spp. seeds, physiological dormancy is installed early in embryo development (Gudin 1994); bioassay (ELISA) (Pipino et al 2013) techniques have detected high ABA levels during the late torpedo stage of embryos of floribunda roses 'Melglory' (1.20 pmol mg -1 ) and 'Cassandra' (2.00 pmol mg -1 ). Mature embryos are no longer dormant when their seeds are fully formed (Bo et al 1995).…”

Study of embryo rescue�in floribunda rose

“…Burger et al (1990) used immature embryos as explant source for in vitro organogenesis and plant regeneration. Subsequently, Gudin (1994) and Marchant et al (1994) reported embryo rescue of Rosa hybrida and English roses. The present investigation was undertaken to establish an efficient protocol for embryo rescue in floribunda roses by manipulating growth media and culture conditions.…”

Embryo Rescue

“…In some genera like Tulipa [26], Rosa [35], or Prunus [36], cold treatments of 4-5 • C for several weeks improved significantly the success in the culture of rescued embryos. Again, the natural requirements for germination of the species provide considerable information for starting experiments.…”