102 POSTER SESSION 4B (Abstr. 197–201) Cell & Tissue Culture—Landscape Plants
Jing-Tian Ling, Henock Zerit, and Roger J. Sauve
Partially expanded male catkins at the pre-pollen shedding stage of Quercus rubra L. and Quercus bicolor Willd. were cultured on MS medium supplemented with BA or 2,4D Explants on 2,4D produced a yellow embryogenic callus, seeming to originate from the pedicels. Subsequent transfers to BA and then, MS without growth regulators, resulted in callus proliferation. After ten weeks in culture, white embryoids developed from the callus of Q. bicolor. Separated and individually cultured embryoids underwent direct, repetitive embryogenesis. Upon transfer to ½-strength MS, embryoid germination and plant regeneration occurred, Callus of Q. rubra degenerated after five months in culture, failing to produce embryogenic structures.
Nawab Ali, Robert Skirvin, Walter E. Splittstoesser, and William L. George
Cucumber (Cucumis sativus L.) seeds of `Marketer', `Marketmore', `Wisconsin SMR-18', `Tablegreen', `Spotfree', and `China' were stored at 3C and 38% relative humidity for up to 26 years. Seed older than 13 years did not germinate. Cultivars stored 10 years gave 80% germination, except Wisconsin SMR-18' (40%). Ten-year-old seeds were separated from their seedcoats, and cotyledons were excised into six segments. Explants were placed on Murashige and Skoog medium with all combinations of BAP (0, 1,2, and 3 mg·liter-1) and NAA (0, 0.1,0.2, and 0.3 mg·liter-1). Plants were obtained from culture for all cultivars grown on medium containing NAA and 1 mg BAP/liter. No plants were regenerated when BAP or NAA was lacking. Chemical names used: benzylaminopurine (BAP), 1-naphthaleneacetic acid (NAA).
Yaseen Mohamed-Yaseen, Raymond J. Schnell, Robert J. Knight, and T.L. Davenport
A procedure was developed to regenerate plants via tissue culture from embryonic axes of mature avocado seeds. Explants were cultured in Murashige and Skoog (MS) medium supplemented with benzyladenine (BA) and naphthalene-acetic acid (NAA) or thidiazuron (TDZ) and NAA. Culture were kept in the dark for 7-10 days to reduce browning resulting from phenolic oxidation. Multiple shoots (5-8) were formed after transfer to light. Further multiplication were achieved using different combination of BA and NAA or TDZ and NAA. Shoots were cultured in MS supplemented with 2mg/l indolebutyric acid (IBA) for 2 weeks then transferred to MS supplemented with lg/l activated charcoal for root induction. Complete plants were obtained in vitro.
Partially expanded male catkins of swamp white oak (Quercus bicolor Willd.) and red oak (Quercus rubra L.) were cultured on Murashige and Skoog (MS) medium supplemented with BA or 2,4-D. Explants on 2,4-D produced a yellow embryogenic callus originating from the junction of the pedicel and peduncle. Subsequent transfers to MS with BA and then MS without growth regulators resulted in callus proliferation. After 10 to 14 weeks in culture, white embryoids developed from the callus of Q. bicolor. Separated and individually cultured embryoids underwent direct, repetitive embryogenesis. Upon transfer to l/2-strength MS, embryoid germination and plant regeneration occurred. Callus of Q. rubra degenerated after 5 months in culture, failing to yield embryogenic structures. Chemical names used: dichlorophenoxyacetic acid (2,4-D); benzyladenine (BA).
Immature leaf laminae and petioles of `Regale' and `Fry' muscadine grapes (Vitis rotundifolia Michx.) were cultured on Nitsch and Nitsch (NN) medium supplemented with 9.0 μm 2,4-D and 4.4 μm BA, and gelled with agar. Callus and original explant tissues were transferred to NN medium containing 10.7 μm NAA and 0.9 μm BA to proliferate embryogenic callus, which, when transferred to NN medium without growth regulators, yielded globular embryos. The embryos matured and germinated after being subcultured to fresh medium without growth regulators. Somatic embryogenesis incidence was greater from petioles than laminae: 90% of `Regale' and 50% of `Fry' petioles formed embryos, compared with 14% and 2% of laminae, respectively. Culturing germinated somatic embryos on NN medium with 1 μm BA enhanced shoot growth. Regenerated plants flowered and appeared morphologically normal. Chemical names used: N-(phenylmethyl)- 1H -purin-6-amine (BA); 2,4-dichlorophenoxyacetic acid (2,4-D); α- naphthaleneacetic acid (NAA).
Lunique Estime, Marie O'Shea, Michael Borst, Jennifer Gerrity, and Shih-Long Liao
1 To whom reprint requests should be addressed. We gratefully acknowledge the technical assistance of Dr. Chee-Kok Chin from the Dept. of Plant Science at Rutgers Univ. This study was conducted in the Dept. of
R.A. May and R.N. Trigiano
Somatic embryogenesis from leaf midrib explants of Dendranthema grandiflora Tzvelev. `Iridon' cultured on modified Murashige and Skoog basal medium (MSB) containing 1.0 mg 2,4-D and 0.2 mg BA/liter was influenced by light and sucrose concentration. Somatic embryos formed directly from explants when cultured on medium containing 9% to 18% sucrose and incubated first in the dark for 28 days, followed by 10 days in light, and then returned to the dark for 14 days. Embryogenesis did not occur in continuous darkness and was drastically reduced when explants were incubated in light only. The most embryos were formed on medium containing either 12% or 15% sucrose; lower concentrations stimulated shoot and root development. Light also mediated embryogenesis from leaf explants of 'other cultivars. White-opaque or occasionally light-green cotyledon-stage somatic embryos germinated on MSB medium without growth regulators but containing 3% sucrose. Twelve of the 23 cultivars evaluated produced somatic embryos, but plants were recovered from only five. Regenerated plants were phenotypically similar to parent plants in growth habit, leaf morphology, and flower color. Chemical names used: N- (phenylmethyl)-1 H- purine-6-amine (BA); (2,4-dichlorophenoxy) acetic acid (2,4-D).
Oral Session 6—Ornamental Plant Breeding Moderator: Daniel F. Warnock 18 July 2005, 4:00–6:00 p.m. Room 107
Song Ping and Ellen B. Peffley
Callus of five onion genotypes representing two species. Allium cepa and A. fistulosum, and their interspecific hybrid were used for establishing suspension cultures. Cultures were derived from callus that had been maintained on solid media and routinely subcultured for four years and from callus induced within six months of this experiment. Long-term callus from which plants were routinely regenerated and newly-induced callus were composed of cells which were, for the most-part, meristem-like with higher mitotic indices than cells from long-term callus which had been maintained as callus but had lost us capability to regenerate plants, these cells were large with small nuclei. Callus from newly-induced and long-term regenerable cultures were selected for further studies. Eight liquid media with factorial combinations of plant growth regulators were tested. Cells cultured in BDS liquid medium supplemented with 0.5 mg/l ABA and 1.0 or 2.0 mg/l 2,4-D without e-BA had higher mitotic indices and plant regeneration percentages than did cells cultured in the same media without ABA and with 6-BA. Suspension cultures from A. fistulosum and interspecific hybrids with A. fistulosum produced the highest numbers of plants regenerated.