SECONDARY EMBRYOGENESIS IN LONG‐TERM CULTURES OF WINTER OILSEED RAPE, BRASSICA NAPUS SSP. OLEIFERA

Abstract

SUMMARYSecondary embryogenic potential of winter oilseed rape, Brassica napus ssp. oleifera (Metzg.) Sinsk. cv. Primor, was maintained for over six years without diminution. Cytological analysis of 22 randomly selected secondary embryoids showed that they were all haploid. Many factors affect secondary embryogenesis in culture. The frequency of secondary embryogenesis was enhanced by the incorporation of 15 g T^ sucrose into the medium; sucrose at 60 to 120 g 1"î nhibited secondary embryogenesis. Incubation in continuous darkness or continuous light led to a marked suppression of secondary embryogenesis. The best light regime for secondary embryogenesis was 16 h light/8 h dark. Incorporation of activated charcoal into the culture medium and the application of gamma radiation suppressed secondary embryogenesis. Further secondary embryogenesis was significantly reduced when only part of the secondary embryoid was cultured. The results discussed are based on the possibility that endogenous growth regulators may be involved in the initiation of secondary embryoids.

Alginate–chitosan coacervation in production of artificial seeds

“…The parental cultures were maintained according to the methods of Shu and Loh. 15 Embryoids suspended in the chitosan solution were pipetted into a wide-bore Koma pipette and dropped into a gently stirred alginate solution. The resultant capsule comprised embryoid in a liquid chitosan core encased in a hard alginate shell.…”

High frequency production of embryos from liquid flask cultures of oilseed rape

“…Primor were maintained according to dispensed into a 5-cm (diameter) Petri dish. Therefore, the methods of Shu and Loh (1987). Four types of callus each plate contained about 0.15 mL PCV of cells.…”

Extracellular localization of napin in the embryogenic tissues of Brassica napus spp. oleifera

“…Most of these embryos, when detached from the parental tissue and sub-cultured on a Murashige and Skoog (1962) medium supplemented with the sucrose 2% (w/v), had the capacity to produce large numbers of secondary embryos on the hypocotyl surface. This embryogenic/embryoid culture has been maintained for more than 20 yr via the monthly sub-culture of the secondary embryos without diminution (Shu and Loh 1987;Namasivayam 2004). Based on the histological and ultrastructural studies on this system, a unique ultrastructural feature designated as the extracellular matrix (ECM) was observed on the surface of the pre-embryogenic (PEC) embryos but not on the non-embryogenic (NEC) individuals .…”