0000000001005888
AUTHOR
B. Haccius
Adventitious bud formation on isolated leaves and its significance for mutation breeding
Since a mutation is a unicellular event, irradiation of a multicellular meristem results in the so-called diplontic selection. This competition between the mutated cell and the surrounding non-mutated cells is often lost by the mutated cell, causing a low frequency of mutated plants and a narrow mutation spectrum. When a mutated cell survives, chimeras are automatically formed because most apices consist of a number of fairly independent groups of cell layers. Such an undesirable situation can be improved by growing complete plants from only one cell, resulting in a high frequency of solid, non-chimeral mutants and a wide mutation spectrum. Many plant species can be stimulated to form adven…
Ein transplantierbarer embryogener Callus aus Nucellusgewebe vonCynanchum vincetoxicum und die Rolle globul�rer Vorstadien in der Entwicklungsgeschichte nicht-zygotischer Embryonen
Unbestaubte Fruchtknoten vonCynanchum vincetoxicum, C. medium undC. nigrum wurden steril exzidiert und in Kultur genommen. Nach 5–10 Wochen brachen aus einigen derC. nigrum-Explantate zahlreiche grune Pflanzchen hervor. Schnittpraparaten war zu entnehmen, das es sich um von den Nucellus-Zellen der unbefruchteten Ovula abstammende Adventivembryonen handelt. Aus einem callusierenden Fruchtknoten vonC. vincetoxicum lies sich schlieslich ein embryogener Callus gewinnen, den wir schon seit mehr als 3 Jahren in Kultur haben. Sowohl die nucellaren als auch die callogenen Keimlinge konnten in Erde ubertragen und zu bluhenden Pflanzen weiterkultiviert werden.
Versuche zur somatischen Beeinflussung der Organbildung pflanzlicher Embryonen
Experiments on influencing cotyledon formation in embryos ofEranthis hiemalis are reported. By treating the seeds with 100–2000 ppm solutions of 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, 2-methyl-4-chlorophenoxyacetic acid, α-naphthylacetic acid and even isopropyl N-phenyl carbamate one can obtain significant increases in twinning and in cotyledon anomalies (syncotyly and pleiocotyly of all degrees). Embryos can be successfully treated until approximately 2 weeks after initial opening of the follicles. X-radiations achieve the same effect, with doses of 2000–4000r corresponding to the treatments with 1000–2000 ppm 2,4-D-solutions. By using weaker concentrations and …