Isolation of Egg Cells from Allium fistulosum
葱卵细胞的分离

Viable egg cells of Allium fistulosum were isolated by enzymatic digestion and mechanical dissection. The ovules were incu-bated in an enzymatic solution containing 0-0.8% pectolyse Y-23, 0-1.2% pectinase (Serva), 0-1.2% cellulase (Onozuka R-S), 0-1% hemicellulase (Sigma) and 6%-12% mannitol for 20-40 min to remove the outer integument. Then ovules were tr-ansferred into an isolating solution without enzymes for mechanical dissection. The ovules were cut from the middle part, and the micropylar part was gently extruded by use of a dissection needle. In general, the three cells of the egg apparatus spilled out from the cut end of the ovule. The enzymatic solution containing 0.2% pectolyse Y-23, 0.8% pectinase (Serva), 0.8% cellulase (Onozuka RS), 0.5%hemicellulase (Sigma) and 10% mannitol was best for isolating about 18 egg cells from 30 ovules in 2 h. The isolated egg cells could be used for in vitro fertilization to explore the fertilization mechanism and for egg development with molecular biological methods.