Cotyledon Protoplasts Research Articles

Plant Regeneration from Seedling Cotyledon Protoplasts

Protoplasts were isolated by enzyme treatment from etiolated and green cotyledons of young seedlings of seven plant species, namely Brassica campestris , B. napus , B. oleracea , Datura innoxia , Hyoscyamus niger , Medicago sativa and Nicotiana tabacum . The plating efficiency in all cases except H. niger was high, reaching up to 83% in N. tabacum . Plant regeneration from protoplast derived colonies of B. oleracea , D. innoxia , M. sativa and N. tabacum confirmed the totipotency of cotyledon protoplasts.

Colony Formation by Cotyledonary Protoplasts of Cyamopsis tetragonoloba L.

Cotyledonary protoplasts of the legume Cyamopsis tetragonoloba resynthesise cell walls and undergo sustained divisions to produce multicellular colonies in two weeks. Preculture of cotyledons in hormone-enriched medium stimulated the division of protoplasts. The division frequency of the protoplasts could also be enhanced considerably by incubation of cotyledons at low temperature of 10°C for 48 h. If the cold conditioning of cotyledons was done in presence of hormones there was a higher frequency of divisions than in individual treatments and the protoplasts divided within 48h of culture. Upon transfer to a medium of low osmotic potential, the colonies developed calli.

Isolation and Callus Formation from Cotyledon Protoplasts of Pine (Pinus pinaster)

Summary Protoplasts were isolated from cotyledons of pine ( Pinus pinaster SOL.). The protoplasts exhibited a high frequency of spontaneous fusion, which was reduced by overnight incubation in low concentration of enzymes (total = 0.16 %, w/v). Sustained division of the regenerated cells was achieved by pretreatment of the cotyledons in solutions containing BA + NAA or 2,4-D alone. The media used for protoplast isolation, washing and culture consisted of Murashige-Skoog mineral salts with various organic supplements, BA and NAA. Best results were obtained in a culture medium adjusted at 0.7 M.

Ribosomal RNA metabolism in cucumber leaf mesophyll protoplasts.

Aspects of the metabolism of RNA have been studied in enzymatically isolated protoplasts from cotyledon and first leaf mesophyll tissue of two cultivars of cucumber. The first leaf mesophyll protoplasts incorporated (3H)-uridine into ribosomal RNA at a constant rate for up to 25 hr in a simple salts medium and for up to 45 hr in a growth medium. Pulse-chase labelling experiments on such preparations showed a rapid dilution of the intracellular (3H)-uridine pool(s) and a high metabolic rate in the cells in one cultivar but not in another. Gel electrophoretic analysis of the RNA from both cotyledon and first leaf protoplasts showed that both protoplast types incorporated either (14C)- or (3H)-uridine into ribosomal RNA species. Incorporation of (3H)-uridine into chloroplasts RNA was minimal in cotyledon protoplasts, but significant in leaf protoplasts. Greater incorporation into the chloroplast RNA species could be achieved by longer pulses. Synthesis of all of the ribosomal RNA species was sensitive to actinomycin D at 10 and 25 mug/ml concentrations in all protoplasts tested.