Isolation of Egg Cells from Allium cepa L.

Abstract: Viable egg cells of Allium cepa L. were isolated using enzymic digestion and mechanical dissection. The onion ovules were incubated in an enzymic solution for 50~110 min and then peeled its two intaguments. The outline of embryo sac in nucellus was seen clearly. Using a dissecting needle cutting necellus transversely and pushing its micropyle part， three cells of egg apparatus could be released from cut end of the nucellus. The egg cell could be separated with two synergids， reaching the purpose of isolation of onion egg cell. Enzymes are very important for isolating egg cell， and in optimal enzyme solution containing 0.02% Pectolyse Y-23， 0.08% Pectinase (Serva)， 0.05% Cellulase (Onozuka RS)， 0.05% Hemicellulase (Sigma)， 10 egg cells (41.67%) could be isolated from 24 ovules in 1 h. With embryo sac development， two synergids display dimorphism in size. The isolation of onion egg cells makes a base for its in vitro fertilization， and provides the condition to study onion egg development using methods of molecular biology.

CSTR: 32200.14.cjcb.2012.11.0008